Rozprawy doktorskie: „Engine cooling system”

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Frick, Peyton M. "A hydraulic actuated thermal management system for large displacement engine cooling systems". Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1193080466/.

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Kendrick, Clint Edward. "Development of model for large-bore engine cooling systems". Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8721.

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Master of Science
Department of Mechanical and Nuclear Engineering
Kirby S. Chapman
The purpose of this thesis is to present on the development and results of the cooling system logic tree and model developed as part of the Pipeline Research Council International, Inc (PRCI) funded project at the Kansas State National Gas Machinery Laboratory. PRCI noticed that many of the legacy engines utilized in the natural gas transmission industry were plagued by cooling system problems. As such, a need existed to better understand the heat transfer mechanisms from the combusting gases to the cooling water, and then from the cooling water to the environment. To meet this need, a logic tree was developed to provide guidance on how to balance and identify problems within the cooling system and schedule appropriate maintenance. Utilizing information taken from OEM operating guides, a cooling system model was developed to supplement the logic tree in providing further guidance and understanding of cooling system operation. The cooling system model calculates the heat loads experienced within the engine cooling system, the pressures within the system, and the temperatures exiting the cooling equipment. The cooling system engineering model was developed based upon the fluid dynamics, thermodynamics, and heat transfer experienced by the coolant within the system. The inputs of the model are familiar to the operating companies and include the characteristics of the engine and coolant piping system, coolant chemistry, and engine oil system characteristics. Included in the model are the various components that collectively comprise the engine cooling system, including the water cooling pump, aftercooler, surge tank, fin-fan units, and oil cooler. The results of the Excel-based model were then compared to available field data to determine the validity of the model. The cooling system model was then used to conduct a parametric investigation of various operating conditions including part vs. full load and engine speed, turbocharger performance, and changes in ambient conditions. The results of this parametric investigation are summarized as charts and tables that are presented as part of this thesis.

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Sastry, Sudeep. "A Thermoacoustic Engine Refrigerator System for Space Exploration Mission". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1301588899.

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Sivard, Henrik. "Development and Implementation of a Controllable Thermostat for an Engine Cooling System". Thesis, KTH, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-104016.

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Reducing fuel consumption is one of the main aims when developing new trucks at Scania. For instance, there are a lot of new EU regulations on what emission levels are allowed. Also, having a low fuel consumption gives Scania an edge over their competitors. This master thesis will investigate one possible way of reducing the fuel consumption in a truck. The aim is to allow a higher engine temperature which gives a higher oil temperature causing less friction in the engine. Thus leading to a more ecient engine and reduced fuel consumption. This needs to be done without risking that the engine overheats. The method used to achieve this is a controllable thermostat which regulates the engine temperature with respect to dierent driving scenarios. In this work a control strategy for a controllable thermostat is produced with help of a Simulik environment where it's tested. A controllable thermostat consisting of a three way valve and an actuator is then installed in a truck and tested on roads. The tests in the truck shows that the controllable thermostat can eciently regulate the engine temperature to dierent reference temperatures and results from simulations showed that a fuel reduction is possible.

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Johansson, Adam, i Jonas Gunnarsson. "Predicting Flow Dynamics of an Entire Engine Cooling System Using 3D CFD". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62763.

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A combustion engine generates a lot of heat which need to be cooled to prevent damages to the engine and the surrounding parts. If the cooling system can not provide enough cooling to keep the engine in a well defined range of temperatures performance and durability will decrease and emissions increase. It is also important that the cooling system do not over-cool the engine, since this may result in rough running, increased engine friction and an overall negative performance. The aim of this thesis work is to create a complete 3D digital model of the cooling system for the first generation VED4 HP with CFD in STAR-CCM+. The simulated results are compared to available experimental data for validation. Today the entire system is being modeled with 1D CFD. One of the selected components in the cooling system being model in 3D at Volvo Cars is the water jacket. The 3D CFD model depends on the 1D CFD model for the boundary conditions which is an ineffective and time consuming process, sending data back and forth between the models when making changes. A 3D CFD model is not only more accurate than the 1D CFD model, since it capture the 3D flow phenomenas but it also allows parts or areas to be studied in detail. A study of four different turbulence models is conducted on the water jacket and on an arbitrary pipe in the cooling system. A mesh study is carried on the water jacket, the same arbitrary pipe and on the thermostat, both for the opened and closed thermostat. These studies are done with regard to pressure drop only. The study yields a low Reynolds model with the k-ε v2f turbulence model gave the best results. There is a discrepancy between the simulated results and the experiments. Main reasons to this may be the difference in the geometry used in this thesis for the digital model and the geometry used for the experiments together with the inaccuracies in the experimental data. The overall deviation is larger for a case with closed thermostat than for a case with an open thermostat. With the correct geometry and more accurate experimental data the simulations should be a close representation of reality.

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Ng, Eton Yat-Tuen, i eton_ng@hotmail com. "Vehicle engine cooling systems: assessment and improvement of wind-tunnel based evaluation methods". RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2002. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080422.100014.

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The high complexity of vehicle front-end design, arising from considerations of aerodynamics, safety and styling, causes the airflow velocity profile at the radiator face to be highly distorted, leading to potentially reduced airflow volume for heat dissipation. A flow visualisation study showed that the bumper bar significantly influenced the cooling airflow, leading to three-dimensional vortices in its wake and generating an area of relatively low velocity across at least one third of the radiator core. Since repeatability and accuracy of on-road testing are prejudiced by weather conditions, wind-tunnel testing is often preferred to solve cooling airflow problems. However, there are constraints that limit the accuracy of reproducing on-road cooling performance from wind-tunnel simulations. These constraints included inability to simulate atmospheric conditions, limited tunnel test section sizes (blockage effects) and lack of ground effect simulations. The work presented in this thesis involved use of on-road and wind-tunnel tests to investigate the effects of most common constraints present in wind tunnels on accuracy of the simulations of engine cooling performance and radiator airflow profiles. To aid this investigation, an experimental technique for quantifying radiator airflow velocity distribution and an analytical model for predicting the heat dissipation rate of a radiator were developed. A four-hole dynamic pressure probe (TFI Cobra probe) was also used to document flow fields in proximity to a section of radiator core in a wind tunnel in order to investigate the effect of airflow maldistribution on radiator heat-transfer performance. In order to cope with the inability to simulate ambient temperature, the technique of Specific Dissipation (SD) was used, which had previously been shown to overcome this problem.

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Prado, Wesley Bolognesi. "Simulação do sistema de arrefecimento de motores diesel em Matlab-Simulink". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-11022016-112753/.

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Programa computacional em Matlab-Simulink para simular o comportamento do sistema de arrefecimento de veículos comerciais (vans, ônibus e caminhões) equipados com motores diesel. O programa está embasado em uma modelagem matemática que visa caracterizar o funcionamento dos componentes principais do sistema: motor, radiador, termostato, by-pass e bomba d\'água. Tendo como entrada dados característicos do veículo em estudo, o programa computacional fornece a distribuição de temperatura ao longo do tempo para o líquido de arrefecimento - parâmetro preponderante em uma análise do sistema. Os resultados da simulação permitem aos projetistas prever a atuação do sistema de arrefecimento em diversas condições, o que possibilita a realização de um número menor de testes de pista. Os benefícios de um sistema de arrefecimento projetado adequadamente podem ser notados em relação à economia de combustível, ao aumento de desempenho e à redução do desgaste de determinadas peças do motor e da emissão de poluentes.
A software was developed having Matlab-Simulink as basis and it simulates the behavior of the cooling system in commercial vehicles (vans, bus and trucks) equipped with diesel engines. The program is based on mathematical models to describe the main components of the system: engine, radiator, thermostat, by-pass and water pump. Having as input data the features of the vehicle in studied, the software supplies the cooling fluid temperature distribution during certain time - preponderant parameter in the analysis of the system. The results of the simulation allow the designers to foresee the cooling system performance in several conditions, decreasing the number of track tests. The benefits of an adequate designed cooling system project can be noticed considering fuel economy, performance improvement and decrease of wearing of specific parts in the engine as well as pollutant emissions.

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Ismail, Basel Ismail A. "The heat transfer and the soot deposition characteristics in diesel engine exhaust gas recirculation system cooling devices /". *McMaster only, 2004.

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Kerachian, Amirali. "Implementation, Validation, and Evaluation of 1D-3D CFD Co-simulation for Cooling System of Internal Combustion Engine". Thesis, KTH, Fordonsdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280563.

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Internal combustion engines, electric motors and batteries generate a significant amount of heat during operation that needs to be extracted by cooling systems. A cooling system is designed and installed to extract the generated heat and maintain the system temperature in an optimal range. Overheating has several unfavorable outcomes such as less durability and lower energy efficiency. The cooling system consists of several components such as hoses, flow splitters, valves, heat exchangers, coolant, pump, etc. The coolant, as the working fluid, is pumped to different heat generator component to enable the cooling down process. Computational Fluid Dynamics (CFD) is a powerful and cost efficient tool to simulate the cooling processes, design, and evaluate the performance of a cooling system. Generally, one dimensional CFD is a common approach to interpret and explain the cooling processes in the automotive industry due to its high flexibility and computational cost efficiency. Also, three dimensional CFD is employed whenever it is required to study complex physical phenomena and provide detailed information. Additionally, it is possible to couple one dimensional and three dimensional CFD approaches to simulate cooling processes. Not only is the coupled 1D-3D CFD approach able to capture complicated physical processes but also is flexible and cost efficient. The objective of this master thesis is to implement 1D-3D CFD coupled simulation on internal combustion engines’ cooling system and evaluate the advantages and disadvantages of this method. The performance of this method is examined in different case studies with different flow and geometrical characteristics. The effect of various turbulence models and numerical settings are investigated on the quality of the coupled simulations’ results. The coupled simulations are carried out using GT-SUITE and STAR-CCM+ software. The performed simulations show that the coupling method is a convenient approach which is able to capture detailed physics with high precision requiring reasonable computational costs. The results of the coupled simulations depict agreement with the uncoupled 1D CFD simulations, although some discrepancies are observed in complex case studies. Also, it is shown that the coupled simulations are sensitive to numerical settings and physical models, consequently, the case setup should be optimized carefully.
Förbränningsmotorer, elmotorer och batterier genererar en betydande mängd värme under drift som behöver extraheras av kylsystem. Ett kylsystem är utformat och installerat för att extrahera den genererade värmen och hålla systemtemperaturen i ett optimalt intervall. Överhettning har flera ogynnsamma följder, som mindre hållbarhet och lägre energieffektivitet. Kylsystemet består av flera komponenter, till exempel slangar, flödesdelare, ventiler, värmeväxlare, kylvätska, pump etc. Kylvätskan, som arbetsvätska pumpas till olika värmegenerator-komponenter för att möjliggöra nedkylningsprocessen.Computational Fluid Dynamics (CFD) är ett kraftfullt och kostnadseffektivt verktyg för att simulera kylprocesserna, utforma och utvärdera prestanda för ett kylsystem. I allmänhet är endimensionell CFD en vanlig metod för att tolka och förklara kylningsprocesserna i bilindustrin på grund av dess höga flexibilitet och beräkningseffektivitet. Dessutom används tredimensionell CFD när det krävs, för att studera komplexa fysiska fenomen och tillhandahålla detaljerad information. Dessutom är det möjligt att koppla ihop en- och tredimensionell CFD-metod för att simulera kylningsprocesser. Inte bara är den kopplade 1D-3D CFD-metoden möjlig för att betrakta komplicerade fysiska processer, utan är även flexibel och kostnadseffektiv.Syftet med detta examensarbete är att implementera 1D-3D CFD kopplad simulering på förbränningsmotorns kylsystem och utvärdera fördelarna och nackdelarna med denna metod. Uppträdandet av denna metod undersöks i olika fallstudier med olika flöde och geometriska egenskaper. Effekterna av olika turbulensmodeller och numeriska inställningar undersöks genom kvaliteten på resultaten hos kopplingens simuleringar. De kopplade simuleringarna utförs med hjälp av mjukvaran GT-SUITE och STAR CCM +.De utförda simuleringarna visar att kopplingsmetoden är ett bekvämt tillvägagångssätt som kan fånga detaljerad fysik med hög precision till rimliga beräkningskostnader. Resultaten av de kopplade simuleringarna visar överensstämmelse med de frikopplade 1D CFD-simuleringarna, även om vissa avvikelser observeras i komplexa fallstudier. Det visas också att de kopplade simuleringarna är känsliga för numeriska inställningar och fysiska modeller, därför bör fallinställningen optimeras noggrant.

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Abdul-Jalal, Rifqi I. "Engine thermal management with model predictive control". Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/24274.

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The global greenhouse gas CO2 emission from the transportation sector is very significant. To reduce this gas emission, EU has set an average target of not more than 95 CO2/km for new passenger cars by the year 2020. A great reduction is still required to achieve the CO2 emission target in 2020, and many different approaches are being considered. This thesis focuses on the thermal management of the engine as an area that promise significant improvement of fuel efficiency with relatively small changes. The review of the literature shows that thermal management can improve engine efficiency through the friction reduction, improved air-fuel mixing, reduced heat loss, increased engine volumetric efficiency, suppressed knock, reduce radiator fan speed and reduction of other toxic emissions such as CO, HC and NOx. Like heat loss and friction, most emissions can be reduced in high temperature condition, but this may lead to poor volumetric efficiency and make the engine more prone to knock. The temperature trade-off study is conducted in simulation using a GT-SUITE engine model coupled with the FE in-cylinder wall structure and cooling system. The result is a map of the best operating temperature over engine speed and load. To quantify the benefit of this map, eight driving styles from the legislative and research test cycles are being compared using an immediate application of the optimal temperature, and significant improvements are found for urban style driving, while operation at higher load (motorway style driving) shows only small efficiency gains. The fuel consumption saving predicted in the urban style of driving is more than 4%. This assess the chance of following the temperature set point over a cycle, the temperature reference is analysed for all eight types of drive cycles using autocorrelation, lag plot and power spectral density. The analysis consistently shows that the highest volatility is recorded in the Artemis Urban Drive Cycle: the autocorrelation disappears after only 5.4 seconds, while the power spectral density shows a drop off around 0.09Hz. This means fast control action is required to implement the optimal temperature before it changes again. Model Predictive Control (MPC) is an optimal controller with a receding horizon, and it is well known for its ability to handle multivariable control problems for linear systems with input and state limits. The MPC controller can anticipate future events and can take control actions accordingly, especially if disturbances are known in advance. The main difficulty when applying MPC to thermal management is the non-linearity caused by changes in flow rate. Manipulating both the water pump and valve improves the control authority, but it also amplifies the nonlinearity of the system. Common linearization approaches like Jacobian Linearization around one or several operating points are tested, by found to be only moderately successful. Instead, a novel approach is pursued using feedback linearization of the plant model. This uses an algebraic transformation of the plant inputs to turn the nonlinear systems dynamics into a fully or predominantly linear system. The MPC controller can work with the linear model, while the actual control inputs are found using an inverse transformation. The Feedback Linearization MPC of the cooling system model is implemented and testing using MathWork Simulink®. The process includes the model transformation approach, model fitting, the transformation of the constraints and the tuning of the MPC controller. The simulation shows good temperature tracking performance, and this demonstrates that a MPC controller with feedback linearization is a suitable approach to thermal management. The controller strategy is then validated in a test rig replicating an actual engine cooling system. The new MPC controller is again evaluated over the eight driving cycles. The average water pump speed is reduced by 9.1% compared to the conventional cooling system, while maintaining good temperature tracking. The controller performance further improves with future disturbance anticipation by 20.5% for the temperature tracking (calculated by RMSE), 6.8% reduction of the average water pump speed, 47.3% reduction of the average valve movement and 34.0% reduction of the average radiator fan speed.

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Eroglu, Sinan. "Coupling of CFD analysis of the coolant flow with the FE thermal analysis of a diesel engine". Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/12655.

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In the process of engine design, it is important for the engine designer to predict the accurate component temperatures. Controlling the temperature of engine components requires a better understanding of the coolant behaviour in the coolant jacket of an engine which is critical to internal combustion engine design, The studies reported in the literature emphasize the influence of the cooling system on other engine operation such as exhaust emission, fuel consumption and engine wear. In this context, much work has been done with the purpose of improving the coolant jacket design and components of the cooling system to achieve higher performance. (Some of these studies) Previous researches have shown the possibility of achieving higher engine efficiency and performance with higher coolant temperature. This project aims at understanding the coolant flow behaviour in the coolant jackets of a diesel engine and investigating the possibility of running the engine at higher coolant temperatures by predicting the temperature distribution of the structure which is required for the assessment of the durability ofthe engine components. In this thesis, CFD (Computational Fluid Dynamics) and FE (Finite Element) techniques are used to study coolant flow in the coolant jackets and to predict the temperature distribution within the engine structure respectively. The objectives are to develop an FE model of the engine structure for thermal analyses and a CFD model of the fluid domain for the coolant flow CFD analyses. A number of case studies are carried out with the purpose of determining the most suitable technique for accurate temperature prediction. The methodology of manual coupling approach between CFD and FE analyses, which is more widely used in industry, and conjugate approach are demonstrated. Using these approaches, thermal analysis of the engine is conducted with the purpose of identifying the thermally critical locations throughout the engine. Furthermore, the influences of higher coolant temperature on these thermally critical regions of the engine are highlighted by carrying out four case studies with coolant inlet temperatures of 110°C, !ISOC, 117.5"C and !20°C. The temperature rise at the particular points around thermally critical regions is found to be in the range of 3-9 degrees at the higher coolant temperatures. This slight increase in temperature of critical locations may affect the durability of the structure. However, without carrying out the structural analyses it is not possible to comment on the durability of the engine structure. The effects of surface roughness and viscosity on heat transfer rate are also investigated and shown to be insignificant.

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Neves, Ricardo Pereira das. "Simplified engine/nacelle heat transfer case analysis via CFD modeling for supporting the preliminary design of nacelle cooling/ventilation system". Instituto Tecnológico de Aeronáutica, 2009. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=861.

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An aeronautical engine is a complex machine composed of different components operating at different temperatures that in conjunction with the nacelle creates a crowded region with the coupled heat transfer mechanisms to be covered by the nacelle cooling/ventilation system. The final configuration of this system is defined through a demanding refinement of the preliminary design. For this reason the preliminary design is considered the key point and as a rule it can be based on the use of similar design scaling or by the use of numerical approaches. The numerical approaches available are the use of a one-dimensional heat transfer analysis or a complete heat transfer analysis via Computational Fluid Dynamics, or CFD. The short lead time usually available to get the nacelle ready leads the using of a more simplified analysis. Even though this simplified analysis is a lesser laborious activity than a more complete heat transfer analysis, it is still a relatively complicated task. Thus this work aims at presenting a simple methodology for supporting the preliminary design of nacelle cooling/ventilation which is basically relies on confirming if such system is really necessary taking into consideration the temperature distribution in the region between the engine/nacelle and the specified limits. In this case, the proposed methodology presented in this work is concerning to the natural convection analysis in a bidimensional engine/nacelle model by the use of CFD. In view of the fact that there is no specific literature reference available about such methodology or the natural convection analysis in an analogous model configuration or even experimental tests results, it was decided to utilize the studies about natural convection in concentric cylinders in the model validation process and to show the suitability of the proposed methodology, it was directly compared to the natural convection analysis in a simplified tridimensional engine/nacelle model by the use of CFD tool which would be performed by the manufacturer.

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Khodabakhshian, Mohammad. "Improving Fuel Efficiency of Commercial Vehicles through Optimal Control of Energy Buffers". Doctoral thesis, KTH, Mekatronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-181071.

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Fuel consumption reduction is one of the main challenges in the automotiveindustry due to its economical and environmental impacts as well as legalregulations. While fuel consumption reduction is important for all vehicles,it has larger benefits for commercial ones due to their long operational timesand much higher fuel consumption. Optimal control of multiple energy buffers within the vehicle proves aneffective approach for reducing energy consumption. Energy is temporarilystored in a buffer when its cost is small and released when it is relativelyexpensive. An example of an energy buffer is the vehicle body. Before goingup a hill, the vehicle can accelerate to increase its kinetic energy, which canthen be consumed on the uphill stretch to reduce the engine load. The simplestrategy proves effective for reducing fuel consumption. The thesis generalizes the energy buffer concept to various vehicular componentswith distinct physical disciplines so that they share the same modelstructure reflecting energy flow. The thesis furthermore improves widely appliedcontrol methods and apply them to new applications. The contribution of the thesis can be summarized as follows: • Developing a new function to make the equivalent consumption minimizationstrategy (ECMS) controller (which is one of the well-knownoptimal energy management methods in hybrid electric vehicles (HEVs))more robust. • Developing an integrated controller to optimize torque split and gearnumber simultaneously for both reducing fuel consumption and improvingdrivability of HEVs. • Developing a one-step prediction control method for improving the gearchanging decision. • Studying the potential fuel efficiency improvement of using electromechanicalbrake (EMB) on a hybrid electric city bus. • Evaluating the potential improvement of fuel economy of the electricallyactuated engine cooling system through the off-line global optimizationmethod. • Developing a linear time variant model predictive controller (LTV-MPC)for the real-time control of the electric engine cooling system of heavytrucks and implementing it on a real truck.

QC 20160128

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Woollen, Peter. "Gas in engine cooling systems : occurrence, effects and mitigation". Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/11740.

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The presence of gas in engine liquid cooling systems can have severe consequences for engine efficiency and life. The presence of stagnant, trapped gases will result in cooling system hotspots, causing gallery wall degradation through thermal stresses, fatigue and eventual cracking. The presence of entrained, transient gases in the coolant flow will act to reduce its bulk thermal properties and the performance of the system s coolant pump; critically the liquid flow rate, which will severely affect heat transfer throughout the engine and its ancillaries. The hold-up of gas in the pump s impeller may cause the dynamic seal to run dry, without lubrication or cooling. This poses both an immediate failure threat should the seal overheat and rubber components melt and a long term failure threat from intermittent quench cooling, which causes deposit formation on sealing faces acting to abrade and reduce seal quality. Bubbles in the coolant flow will also act as nucleation sites for cavitation growth. This will reduce the Net Positive Suction Head available (NPSHA) in the coolant flow, exacerbating cavitation and its damaging effects in locations such as the cylinder cooling liners and the pump s impeller. This thesis has analysed the occurrence of trapped gas (air) during the coolant filling process, its behaviour and break-up at engine start, the two-phase character of the coolant flow these processes generate and the effects it has on coolant pump performance. Optical and parametric data has been acquired in each of these studies, providing an understanding of the physical processes occurring, key variables and a means of validating numerical (CFD) code of integral processes. From the fundamental understanding each study has provided design rules, guidelines and validated tools have been developed, helping cooling system designers minimise the occurrence of trapped air during coolant filling, promote its breakup at engine start and to minimise its negative effects in the centrifugal coolant pump. It was concluded that whilst ideally the prevention of cooling system gases should be achieved at source, they are often unavoidable. This is due to the cost implications of finding a cylinder head gasket capable of completely sealing in-cylinder combustion pressures, the regular use of nucleate boiling regimes for engine cooling and the need to design cooling channel geometries to cool engine components and not necessarily to avoid fill entrapped air. Using the provided rules and models, it may be ensured stagnant air is minimised at source and avoided whilst an engine is running. However, to abate the effects of entrained gases in the coolant pump through redesign is undesirable due to the negative effects such changes have on a pump s efficiency and cavitation characteristics. It was concluded that the best solution to entrained gases, unavoidable at source, is to remove them from the coolant flow entirely using phase separation device(s).

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Tapanlis, Orpheas. "Turbine casing impingement cooling systems". Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711623.

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Bouwer, Werner. "Designing a dynamic thermal and energy system simulation scheme for cross industry applications / W. Bouwer". Thesis, North-West University, 2004. http://hdl.handle.net/10394/592.

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The South African economy, which is largely based on heavy industry such as minerals extraction and processing, is by nature very energy intensive. Based on the abundance of coal resources, electricity in South Africa remains amongst the cheapest in the world. Whilst the low electricity price has contributed towards a competitive position, it has also meant that our existing electricity supply is often taken for granted. The economic and environmental benefits of energy efficiency have been well documented. Worldwide, nations are beginning to face up to the challenge of sustainable energy - in other words to alter the way that energy is utilised so that social, environmental and economic aims of sustainable development are supported. South Africa as a developing nation recognises the need for energy efficiency, as it is the most cost effective way of meeting the demands of sustainable development. South Africa, with its unique economic, environmental and social challenges, stands to benefit the most from implementing energy efficiency practices. The Energy Efficiency Strategy for South Africa takes its mandate from the South African White Paper on Energy Policy. It is the first consolidated governmental effort geared towards energy efficiency practices throughout South Africa. The strategy allows for the immediate implementation of low-cost and no-cost interventions, as well as those higher-cost measures with short payback periods. An initial target has been set for an across sector energy efficiency improvement of 12% by 2014. Thermal and energy system simulation is globally recognised as one of the most effective and powerful tools to improve overall energy efficiency. However, because of the usual extreme mathematical nature of most simulation algorithms, coupled with the historically academic environment in which most simulation software is developed, valid perceptions exist that system simulation is too time consuming and cumbersome. It is also commonly known that system simulation is only effective in the hands of highly skilled operators, which are specialists in their prospective fields. Through previous work done in the field, and the design of a dynamic thermal and energy system simulation scheme for cross industry applications, it was shown that system simulation has evolved to such an extent that these perceptions are not valid any more. The South African mining and commercial building industries are two of the major consumers of electricity within South Africa. By improving energy efficiency practices within the building and mining industry, large savings can be realised. An extensive investigation of the literature showed that no general suitable computer simulation software for cross industry mining and building thermal and energy system simulation could be found. Because the heating, ventilation and air conditioning (HVAC) of buildings, closely relate to the ventilation and cooling systems of mines, valuable knowledge from this field was used to identify the requirements and specifications for the design of a new single cross industry dynamic integrated thermal and energy system simulation tool. VISUALQEC was designed and implemented to comply with the needs and requirements identified. A new explicit system component model and explicit system simulation engine, combined with a new improved simulation of mass flow through a system procedure, suggested a marked improvement on overall simulation stability, efficiency and speed. The commercial usability of the new simulation tool was verified for building applications by doing an extensive building energy savings audit. The new simulation tool was further verified by simulating the ventilation and cooling (VC) and underground pumping system of a typical South African gold mine. Initial results proved satisfactory but, more case studies to further verify the accuracy of the implemented cross industry thermal and energy system simulation tool are needed. Because of the stable nature of the new VISUALQEC simulation engine, the power of the simulation process can be further extended to the mathematical optimisation of various system variables. In conclusion, this study highlighted the need for new simulation procedures and system designs for the successful implementation and creation of a single dynamic thermal and energy system simulation tool for cross industry applications. South Africa should take full advantage of the power of thermal and energy system simulation towards creating a more energy efficient society.
Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.

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Badenhorst, Kenneth Merwin. "The simulation of vehicle engine cooling in a climatic chamber". Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1454.

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The simulation of vehicle engine cooling validation in a Climatic chamber will benefit all vehicle manufacturers that are responsible for the design or the localization of parts used in a vehicle's engine cooling system. The ability to test the vehicle in-house allows testing at any time of the year; it provides repeatable and comparative data, and accelerates component level approval, which in itself reduces program timing and cost. For this dissertation road level testing was conducted in Upington using a TD1200 Superflow towing dynamometer, while the in-house testing was performed on a ROTOTEST chassis dynamometer in a Climatic chamber. All tests were conducted according to GENERAL MOTORS SOUTH AFRICA global testing standards. Statistical analyses of the test data were used to determine the relationship between parameters measured and results obtained. The major contributors to the simulation process was identified and implemented to improve measurement quality and test results. The result was an accurate simulation between road and chamber testing, hence the possibility of moving away from road testing and conduct simulated chamber testing. The presented dissertation is useful for the understanding of basic vehicle cooling testing and the methodology of simulated testing in an environmentally controlled chamber.

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Quim, Nelson. "Desenvolvimento de uma metodologia de simulação aplicada ao sistema de arrefecimento veicular". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3150/tde-09082007-182717/.

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Este trabalho visa o estudo de uma metodologia de simulação numérica aplicada ao processo de troca térmica do motor de um veículo de passeio. O processo de troca térmica é essencial para evitar o superaquecimento do motor, que provoca o rompimento do filme de óleo lubrificante dos pistões e, conseqüentemente, o seu travamento. Essa metodologia será útil nos estudos preliminares do sistema de arrefecimento de um veículo na fase inicial de projeto por meio de simulações virtuais, o que possibilitará a redução de protótipos, além de proporcionar um ganho em tempo de resposta. A metodologia utiliza um programa comercial de CFD para a simulação do processo de troca térmica no interior do compartimento do motor do veículo. As simulações foram realizadas com base nos testes físicos em túnel de vento que fazem parte do desenvolvimento e projeto de automóveis em condições de operação que representam situações críticas integrantes da vida operacional. Essas condições operacionais de teste, tais como a velocidade do veículo, as cargas térmicas, a potência dos ventiladores e outros parâmetros foram utilizadas como condições de contorno na validação do modelo do veículo. O processo de validação de modelos é composto por: validações de itens isolados do sistema de arrefecimento, avaliação do efeito da densidade de malha computacional de um modelo completo na vazão de ar nos trocadores de calor e simplificações no modelo para a redução do tempo de processamento. Neste trabalho três modelos distintos de veículos foram utilizados, sendo que dois deles para a validação na comparação com os resultados de túnel vento, enquanto o terceiro modelo foi utilizado para a validação da metodologia através de comparações com os dados obtidos nos testes em pista circular. Os resultados das simulações mostraram variações máximas de 5,5% na temperatura do líquido de arrefecimento na entrada do radiador em relação aos testes. A metodologia de simulação mostrou ser uma poderosa ferramenta de otimização durante a fase de desenvolvimento do projeto e complementando os testes físicos para o sistema de arrefecimento veicular.
The present work is applied to a development of a numerical simulation methodology for a passenger vehicle engine cooling process. The heat exchange process is essential to avoid the engine overheat which may result in the piston oil film separation and consequently its halt. This methodology will be useful for the preliminary studies of the cooling system at the initial phase through the virtual simulations which can reduce the number of prototypes and save proposals\' time response. The methodology uses commercial CFD software for airflow simulation and the thermal process at under hood. The simulations were based on the physical wind tunnel tests that are part of the automotive development, with operational conditions representing critical situations experienced by a vehicle in its operating life. The test conditions, such as vehicle speed, thermal loads, fan power and other parameters were used as the boundary conditions for the model validation. The validation process is based on the following phases: validation of the isolated cooling system components, the effect of mesh density at cooling airflow using a complete vehicle model and model simplification in order to improve the processing time. In this work development, three different models were used; two of them for validation with test tunnel data and the third, was used for methodology validation through the circular road test. The simulation results for tunnel and circular road showed 5.5% of differences for the radiator coolant inlet temperature when compared with physical tests. The methodology of the simulation is a powerful tool for optimization during the development phase and complementing the physical tests for the vehicle cooling systems.

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Lindmark, Susanne. "The role of absorption cooling for reaching sustainable energy systems". Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-319.

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CAMPOS, EDWIN RONALD VALDERRAMA. "MODELING OF THE USE OF NANOFLUIDS IN INTERNAL COMBUSTION ENGINES COOLING SYSTEMS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15694@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Estudou-se a aplicação de nanofluidos no sistema de arrefecimento de motores a combustão interna. Nanofluidos são suspensões de partículas de diâmetro menor que 100 nm em fluidos convencionais de troca de calor, tais como água, óleo, etileno glicol, entre outros. Devido às suas características favoráveis de transferência de calor, em função da suspensão de partículas, metálicas ou não metálicas, com elevada condutividade térmica, nanofluidos têm sido considerados para atuar como fluidos térmicos em diferentes aplicações. Desenvolveram-se modelos matemáticos para operação em regime permanente, na avaliação do efeito das características térmicas e hidráulicas do escoamento do nanofluido nos componentes do sistema de arrefecimento; e em regime transiente, na avaliação do processo de aquecimento do motor. Fez-se uso do pacote EES para a simulação e consideraram-se os seguintes componentes do sistema de arrefecimento automotivo: radiador, camisas do bloco de cilindros, termostato e bomba do líquido de arrefecimento. Foram empregados o método dos parâmetros concentrados e o método (épsilon)-NTU para a modelagem global do sistema monofásico. Diferentes tipos de nanofluidos, com variações na concentração volumétrica de nanopartículas, foram considerados na avaliação desta alternativa em fluidos térmicos visando aplicações automotivas.
The application of nanofluids in cooling systems of internal combustion engines was studied. Nanofluids consist of nanoparticles (with dimension below 100 (u)m) suspended in traditional heat transfer fluids, such as water or ethylene glycol. Given their favourable heat transfer characteristics, because of the suspension of high thermal conductivity particles, metallic or non-metallic, nanofluids have been considered as potential substitutes for conventional heat transfer fluids. Mathematical models were developed for steady-state operation, for the evaluation of thermal and hydraulic behavior of the cooling system, and for transient regime, for the assessment of the engine start-up process. The EES software was employed for the simulation. The following components of the cooling system were considered: radiator, engine cooling jackets, thermostat and coolant pump. Lumped parameter analysis and the effectiveness- NTU method were used for the single-phase system simulation. Different types of nanofluids, with variation on the volume fraction, were considered in this study.

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Mamani, A., G. Quispe i C. Raymundo-Ibañeez. "Electromechanical Device for Temperature Control of Internal Combustion Engines". IOP Publishing Ltd, 2019. http://hdl.handle.net/10757/656303.

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Internal combustion engines are the most commonly used engines in the automotive world. However, these engines lack an overheating prevention system against cooling system failures when they exceed their normal operating temperature. Less experienced drivers (users) usually do not notice overheating until the engine stops, generating economic expenses in engine repairs. As such, this paper describes the design and construction of an electromechanical device to prevent engine overheating. This device is installed in a vehicle and operates independently from the electronic control unit (ECU); it records the coolant temperature and controls air admission to the engine of the vehicle in which it is installed. In addition, a new Arduino-based card will receive signals from a temperature sensor as input and process them according to its programming. Then, it will send signal outputs to the actuators: A servomotor, monitor, LED display, and buzzer. To control the intake flow, a butterfly valve is used with the servomotor. This valve partially or totally restricts the engine airflow, based on the temperature programmed for the Arduino, thus protecting the engine from overheating.

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A'Barrow, Chris. "Aerodynamic design of the coolant delivery system for an intercooled aero gas turbine engine". Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/13539.

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The Advisory Council of Aeronautical Research in Europe (ACARE) has set record emission reduction targets for 2020, in response to increased awareness of global warming issues and the forecast high level of growth in global air traffic. In order to meet this legislation engine designers have to consider new and unconventional designs. An intercooled aero-engine with a heat exchanger (HX) positioned between the IP and HP compressors has the potential to reduce emissions and/or reduce specific fuel consumption relative to conventional engine cycles. In such an engine a coolant delivery system is required to bleed a proportion of the bypass flow, from behind the fan outlet guide vane (FOGV), rapidly diffuse the flow (to reduce pressure loss through the HX modules) and present it to the intercooler (i.e. heat exchanger) modules for cooling. This spent cooling air is then fed back into the bypass duct. To realise the benefits of the intercooled cycle the coolant delivery system must diffuse the flow, within the geometrical constraints, with minimal pressure loss and present it to the heat exchanger modules with suitable flow characteristics over a range of operating conditions. Therefore, a predominately experimental study, complemented with CFD predictions, was undertaken to investigate the design and performance of a coolant delivery system aimed at providing high pressure recovery in a relatively short length. For this to be achieved some pre-diffusion of the flow is required upstream of the offtake (i.e. by making the offtake larger than the captured streamtube), with a controlled diffuser or hybrid diffuser arrangement located downstream of the offtake. Although targeted at an intercooled aero-engine the concept of a system that produces a high pressure recovery in a limited length is applicable to a variety of applications. Experimental data were obtained on a modified existing low speed isothermal annular test facility operating at nominally atmospheric conditions. The offtake must operate aft of the FOGV in a highly complex flow field environment. Hence, a 1½ stage axial flow compressor (IGV, rotor and modified OGV) was used to simulate the unsteady blade wakes, secondary flows, loss cores and other turbo-machinery features that can significantly influence offtake performance. Preliminary numerical (CFD) studies enabled an offtake configuration to be determined and provided understanding of the governing fluid mechanic processes. A relatively small scale, low speed test facility was designed that had the capability to evaluate aerodynamic processes in isolation (i.e. pre-diffusion, controlled diffusion, hybrid diffusion) and full system modelling to enable the complex interaction between these flow processes to be assessed. Hence an optimal system could be characterised in terms of total pressure loss, static pressure recovery and flow profiles at HX inlet. Measurements and numerical predictions are initially presented for a baseline configuration with no offtake present. This enabled the OGV near field region to be characterised and provided a datum, relative to which the effects of introducing an offtake could be assessed. The results showed that in the near field region (i.e. within one chord downstream of the FOGV) the high velocity gradients in the circumferential direction, and associated turbulent shear stresses, dominate the profile mixing and loss production. There is little mixing out of profiles in the radial direction. Furthermore, the relatively large amount of kinetic energy associated with the compressor efflux and its subsequent mixing to a more uniform profile (i.e. reduced blockage) results in a significant static pressure recovery (Cp=5.5%). With the offtake present a variety of configurations were investigated including different levels of pre-diffusion, prior to the offtake, and different offtake positions. This enabled evaluation of the upstream pressure effects and interaction with the upstream FOGV. For very compact systems of short length, such that the gap between the OGV and offtake is relatively small, the amount of pre-diffusion achievable is limited by the offtake pressure field and its impact on the upstream OGV row. This pressure field is also influenced by parameters such as the non-dimensional offtake height and splitter thickness. For systems of increased length a significant amount of flow pre-diffusion can be achieved with little performance penalty (relative to the datum configuration). Hence, the loss associated with mixing blade wakes and secondary flows in an adverse pressure gradient is relatively small. However, the pre-diffusion level is eventually limited, to approximately 1.5, by the increased distortion and pressure losses associated with the captured streamtube. Further measurements were made with various controlled diffuser and hybrid diffusers (of varying area ratio) downstream of the offtake and various levels of pre-diffusion. The flow profile that is presented to the controlled diffuser is directly influenced by the upstream pre-diffusion process. Hence, in this case the upstream-downstream interaction is relatively strong. Conversely, the downstream-upstream interaction, between the controlled diffuser and pre-diffusion process, is relatively weak and thus has little effect on the upstream flow field. The data enabled an optimal system to be characterised (pre-diffusion/controlled diffusion split) in terms of total pressure loss, static pressure recovery and flow profiles at HX inlet. A total system diffusion of 1.8 was achievable with a pre-diffusion of 1.4 and controlled diffusion of 1.25, with further increases in either the pre-diffusion level or the controlled diffuser area ratio destabilising the system. This was achieved with an absolute mass weighted total pressure loss of 11% measured from FOGV inlet to the controlled diffuser exit plane. Utilising a hybrid bled diffuser, combined with the pre-diffusion, enabled a total system diffusion of 2.24 to be achieved. The system incorporated a 6% bleed from the hybrid diffuser and a system total pressure loss of 13%. Experimental and computational results obtained in the current research have provided an understanding of the governing flow mechanisms and quantified the geometric and aerodynamic interaction of the offtake with the FOGV and between the diffusion processes. This has enabled a design methodology to be outlined that provides approximate information on system geometry and performance (in terms of optimal diffusion split and total pressure loss) for future coolant delivery systems with minimal effort. Preliminary design maps have been developed to define the magnitude of the interaction between the offtake and FOGV in terms of the offtake height, pre-diffusion level, the splitter thickness and the axial distance between the fan OGV and offtake. In this way systems of optimal diffusion split, minimum pressure loss and minimal axial length can be determined.

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de, Oliveira Mónica Sandra Abrantes. "The use of air assisted atomised water spray systems for controlled cooling of high temperature forgings". Thesis, University of South Wales, 1999. https://pure.southwales.ac.uk/en/studentthesis/the-use-of-air-assisted-atomised-water-spray-systems-for-controlled-cooling-of-high-temperature-forgings(46c7cbe3-4bc5-443a-b9ea-de43af504fcc).html.

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This thesis describes the work undertaken by the author in collaboration with Wyman-Gordon Forgings, USA, to assist in the development of a cooling system,based on air assisted atomised water sprays primarily for the quenching of aerospace components from high temperatures. The mechanical properties of forgings used in aircraft engines depend on the rate of cooling from the heat treatment solution temperature. It is well known that water quenching produces high cooling rate. Although, the severity of the quench can sometimes produce unacceptable distortion and high residual stresses in the component. For this reason water quenching is only used when a high cooling rate is definitely needed and it is often replaced by a less severe oil quench. However, over the last 10 years the trend to reduce manufacturing costs has led to the forging of parts that are closer to the net shape. In these cases even oil quenching can lead to residual stresses being developed that result in difficulties during the final machining of the engine component. Forced air cooling has been adopted in problem cases where the part is thin enough to attain the desired cooling rate. In many instances, however, the component is of intermediate size or varying in cross section and fan cooling cannot provide the cooling rate which is needed to obtain the desired mechanical properties, whilst oil quenching produces an unacceptable level of residual stresses. The use of air assisted atomised water sprays can provide heat transfer coefficients whose values lie between those for air cooling and oil quenching. Another advantage is that control of the air pressure enables the spray nozzle to operate with a much wider range of water flow rates so that the cooling rate can be readily controlled over the range. This study describes the investigation of the heat transfer characteristics of air assisted atomised water sprays to quench aeroengine components from temperatures of approximately 850°C. New data were obtained at high temperatures for air assisted atomised water sprays operating over a wide range of water mass fluxes, (8.01>w 0 >0kg/m2 .s). In practice the geometry of a component can be complex in shape. Therefore an investigation was also carried out into the application of spray cooling on recessed surfaces. It was found that the surface recess contributes significantly to the reduction in the rate of heat transfer at low and high water mass fluxes, but had little effect at intermediate flow rates. Pulsed sprays were investigated and proposed as a means of controlling heat transfer coefficients for both plane and recessed surfaces. The use of a pulsed spray makes it possible to control the amount of water impacting on a surface per second. It was found that "water off periods of 5 and 10 seconds resulted in a reduction in heat transfer coefficients at low temperatures and also reduced considerably the differences in cooling previously observed between plane and recessed surfaces. A finite element code was used to predict the residual stresses produced in a forged component for a range of spray parameters, and spray arrangements. The data were compared with cooling rates and stress patterns produced by both air and oil quenching. It was found that spray cooling resulted in cooling rates which met the mechanical property specification and provided residual stresses lower than those obtained during oil quenching. Furthermore, simulations of residual stress formation using two different spray arrangements in a typical forging indicated that spray non uniformities can substantially disturb the resultant residual stress patterns which could result in less predictable distortions during final machining. The study of spray cooling presented here suggests that the use of air assisted atomised water sprays has considerable potential and could provide the required cooling rate for individual forgings.

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Iskandar, Marco Antonio. "Análise e projeto de um sistema de controle de arrefecimento de um motor Diesel, visando à redução das emissões e consumo de combustível". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264902.

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Orientador: Alberto Adade Filho
Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-18T21:11:42Z (GMT). No. of bitstreams: 1 Iskandar_MarcoAntonio_M.pdf: 4356371 bytes, checksum: 8b89db3b0ba0eb163732c9073c792ae9 (MD5) Previous issue date: 2011
Resumo: A tecnologia de motores diesel tem sido guiada por legislações cada vez mais severas. Para cumprir com estas legislações os sistemas de controle de emissões estão se desenvolvendo rapidamente visando à disponibilização no mercado de produtos que atendam às normas de emissões, mas com economia no consumo de combustível e maior durabilidade e competitividade nos mercados internacionais, em suma melhoria na relação custo x benefício. Neste contexto, é colocada a análise e projeto de um sistema de controle de arrefecimento do motor Diesel, que objetiva controlar a temperatura de água do motor visando à economia de combustível e redução dos níveis de emissões. Assim, o presente trabalho tem como objetivo a análise e projeto de um sistema substituto ao tradicional sistema de arrefecimento (cooling) do motor Diesel disponível e comumente utilizado no mercado atualmente. O sistema mecatrônico em estudo é composto por uma bomba elétrica de água, um ventilador acionado eletricamente, uma válvula termostática eletronicamente controlada e um algoritmo de controle. Este conjunto visa propiciar um controle preciso da temperatura de água do motor Diesel, dessa forma reduzindo as emissões de poluentes e o consumo de combustível, permitindo, ainda, uma resposta rápida no aquecimento em partida a frio e maior durabilidade do motor. Os ajustes do controlador foram calculados por meio de algoritmos de otimização e co-simulação computacional utilizando dois softwares distintos: GT-Cool (GT-SUITE é marca registrada da Gamma Technologies) e Matlab / Simulink (MATLAB/Simulink é marca registrada da Mathworks)
Abstract: The diesel engine technology has been driven by increasingly stringent laws. To comply with these laws the emissions control systems are rapidly developing in the market aimed at providing products that meet future emissions standards, but savings in fuel consumption and greater durability and competitiveness in international markets, improving cost-benefit ratio. In this context, design and analysis of a control system for cooling the diesel engine, aiming to control the engine water temperature accurately, to save fuel and reduce emissions. The present work has as objective to design a mechatronic system as a substitute to the traditional cooling system of the diesel engine commonly used in the market today. The system under study consists of an electric water pump, an electrically driven fan, an electronically controlled thermostatic valve and a control algorithm. This system is intended to provide a control in water temperature of the diesel engine, thereby reducing pollutant emissions and fuel consumption, allowing also a rapid response to heating in cold start. Controller tuning was calculated by algorithmic through optimization and co-simulation using two distinct computational software GT-Cool (GT-SUITE is a registered trademark of Gamma Technologies) and Matlab / Simulink (MATLAB / Simulink is a registered trademark of Mathworks)
Mestrado
Eletrônica
Mestre em Engenharia Automobilistica

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Burjeta, Michal. "Návrh konceptu separátoru kapaliny pro systém vodního vstřikování u zážehového motoru". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417591.

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Tato práce je zaměřena na systém vodního vstřikování a způsoby zajištění dostatečného množství potřebné kapaliny pro správný chod tohoto systému. Jedním zajímavým a nezávislým řešením je využití odpadních produktů motoru, a to vodní páry produkované spalováním paliva. Pro zajištění kondenzace je nutné zchlazení výfukových plynů pod rosný bod páry, což lze zajistit opatřením výfukového potrubí chladiči. Vzniklý kondenzát je pak potřeba efektivně oddělit od proudu plynů a zachytit. Návrh takovéhoto systému vychází z reálně naměřených dat a jeho následným ověřením pomocí CFD simulace.

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Douxchamps, Pierre-Alexis. "Diesel thermal management optimization for effective efficiency improvement". Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210123.

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This work focuses on the cooling of diesel engines. Facing heavy constraints such

as emissions control or fossil energy management, political leaders are forcing car

manufacturers to drastically reduce the fuel consumption of passenger vehicles. For

instance, in Europe, this fuel consumption has to reach 120 g CO2 km by 2012, namely 25 % reduction from today's level.

Such objectives can only be reached with an optimization of all engines components

from injection strategies to power steering. A classical energy balance of an internal

combustion engine shows four main losses: enthalpy losses at the exhaust, heat

transfer to the cylinder walls, friction losses and external devices driving. An

optimized cooling will improve three of them: the heat transfer losses by increasing

the cylinder walls temperature, the friction losses by reducing the oil viscosity and

the coolant pump power consumption.

A model is first built to simulate the engine thermal behavior from the combustion

itself to the temperatures of the different engine components. It is composed by two

models with different time scales. First, a thermodynamic model computes the in cylinder

pressure and temperature as well as the heat flows for each crank angle.

These heat flows are the main input parameters for the second model: the nodal

one. This last model computes all the engine components temperatures according

to the nodal model theory. The cylinder walls temperature is then given back to

the thermodynamic model to compute the heat flows.

The models are then validated through test bench measurements giving excellent

results for both Mean Effective Pressure and fluids (coolant and oil) temperatures.

The used engine is a 1.9l displacement turbocharged piston engine equipped with

an in-cylinder pressure sensor for the thermodynamic model validation and thermocouples

for the nodal model validation.

The model is then used to optimize the coolant mass flow rate as a function of

the engine temperature level. Simulations have been done for both stationary

conditions with effciency improvement up to 7% for specific points (low load, high

engine speed) and transient ones with a heating time improvement of about 2000s.

This gains are then validated on the test bench showing again good agreement.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Khanna, Yash. "Conceptual design and development of thermal management system for hybrid electric aircraft engine. : A study to develop a physical model and investigate the use of Mobil Jet Oil II as coolant for aircraft electrical propulsion under different scenarios and time horizons". Thesis, Mälardalens högskola, Framtidens energi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-46612.

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The ever-increasing levels of greenhouse gas emissions has led to the scientific community starting to explore the viability of electrical aircraft system, with the most prominent research and product development for hybrid electric system, which forms the transition phase from combustion to fully electric aircrafts. The primary objective of this thesis is to find solutions towards thermal management of the electrical components of a hybrid electric aircraft propulsion system, which generate a significant amount of heat while operating at heavy load conditions required to propel an aircraft. In view of these objectives a micro channel cold plate liquid cooling system, has been dynamically modelled using a combination of lumped parameter and thermal resistance methods of heat transfer analysis. The study investigates the prospects of using Mobil Jet Oil II, typically used as an aircraft lubricant as a coolant for the thermal management system. The primary components of this model are lithium ion battery, DC-AC inverter, permanent magnet motor, cross flow finned micro channel heat exchanger, centrifugal pump and ducts. The electrical components have been dimensioned according to energy storage and load requirements considering their efficiencies and gravimetric power/energy. The system has been simulated and analyzed under different scenarios considering the coolant inlet temperature, air temperature across the heat exchanger and on two-time horizons. Analysis has been done to study the dynamic trends of the component temperature and the coolant at different stages of the system. The scope of the study includes an evaluation of the added weight of the thermal management system under different time horizons and their comparison with results from a reference study. From the simulation results it can be concluded that Mobil Jet Oil II is a promising option as a coolant and therefore its use as a common fluid for gas turbine lubrication and as coolant, will benefit the aircraft as now no extra coolant reservoir is required, allowing reduction in weight carried by the aircraft.

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Sara, Hanna. "Analysis and valorization of new thermal management systems for a vehicle powertrain application". Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0019/document.

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La gestion thermique est un des moyens de réduction de la consommation spécifique d’un véhicule. Avec le réchauffement climatique, les normes de dépollution deviennent de plus en plus sévères et les constructeurs automobiles cherchent à améliorer le rendement des véhicules. Le but de ces travaux de recherche est de valoriser, par simulation numérique, les nouveaux systèmes de gestion thermique en fonction du cycle d’homologation et de la température ambiante.Un modèle de simulation 1-D du moteur et de ses circuits de refroidissement et de lubrification ont été développés en utilisant le logiciel GT-Suite. Quatre cycles d’homologation ont été choisis : NEDC, WLTC, AH et AU. De plus, un nouveau cycle a été proposé durant cette étude. Le bilan d’énergie effectué pendant les différentes phases des cycles souligne l’importance du stockage et de la récupération d’énergie.Le stockage d’énergie dans un volume eau et/ou d’huile abouti à l’amélioration de la montée en température des deux fluides. Plusieurs configurations ont été proposées comme, par exemple, un carter d’huile multifonctionnel.Ainsi, une réduction importante de la consommation en carburant est obtenue.La récupération de chaleur au sein des gaz d’échappement est ensuite mise en oeuvre. L’échangeur est caractérisé sur un banc d’essais puis modélisé. Le réchauffement indirect et direct d’huile abouti à une réduction importante des frottements et de la consommation. Une configuration est proposée afin de contrôler la température maximale de l’huile.Finalement, différentes stratégies comme : le type d’huile, l’isolation du moteur, une température de régulation plus élevée etc… ont été étudiées et valorisées
Thermal management proved itself in improving the fuel efficiency of the engine. Nowadays, automotive companies tend to apply different strategies to answer the greenhouse severe laws. The PhD aim is to valorize and analyze the different thermal management strategies with numerical simulations over different driving cycles and ambient conditions. A 1-D simulation code of the engine and its hydraulic circuits were built using GT-Suite. Four known driving cycles were chosen: NEDC, WLTC, AH and AU. In addition, an in-house developed driving cycle was introduced. An energy balance made over the different stages of the driving cycles underlines the importance of the heat storage and the exhaust heat recovery strategies.Heat recovery was applied over the coolant and the oil at ambient temperatures of -7°C and 20°C. Hot coolant storage and hot oil storage led to improve the coolant and lubricant initial temperatures respectively. Different configurations (total of 7) were proposed and studied. A multifunctional oil sump was introduced. Important fuel consumption savings were obtained. Exhaust heat recovery was then valorized. Heat exchanger was characterized over experimental setup then added to the engine model. Indirect and direct heating of the lubricant as well as both strategies back to back were tested. Remarkable friction reduction and fuel savings were obtained. Special configuration was proposed to control the lubricant high temperature instead of the bypass on the exhaust line. The study ended by valorizing minor strategies as the oil’s grade influence, the engine insulation, high temperature set point …

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Almeida, Fernando Jorge Gonçalves, i João Pedro Brás da Cruz. "Cooling System Analysis". Master's thesis, 2012. http://hdl.handle.net/10316/20538.

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Dissertação de Mestrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra
ABSTRACT This master thesis report describes the behavior of a cooling system based on the power consumption and power losses during the velocity range. The thesis is a report of the behavior of the cooling system to understand were we having more needs to cold down the system. It was used a excel sheet to describe the values of power, losses and efficiencies of the various components of the cooling. With the excel sheets built we studied various cases in the system to show the points more important to take care with the cooling system. Continuing the study, it was showed the power consumptions of the cooling system and also the heat dissipation capacity. The objective included in this thesis is to show that in the regular cooling systems the use of the engine's velocity to move the fan and the coolant pump is not the best choice. Could be currently the less expensive one,but not the best one. This thesis didn’t have the objective to find a solution for a perfect cooling system, but a good report of the problems of the actual cooling systems and where we should spend more time to improve them. This is just a preparatory work for a new work.

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Malone, Ronald L. "Air side heat transfer enhancement for an engine cooling system". 1990. http://catalog.hathitrust.org/api/volumes/oclc/23164761.html.

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Thesis (M.S.)--University of Wisconsin--Madison, 1990.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 90-92).

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Su, Kuanming, i 蘇冠銘. "The Study of the Deaerating Device on the Engine Cooling System". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/82091115561069330054.

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碩士
大葉大學
車輛工程研究所
90
Since the advancement of engine technology, new engines can have much higher power and thermal efficiency, and also much higher combustion temperature and pressure inside the cylinder than before. The higher combustion temperature makes coolant temperature higher, while the higher combustion pressure possibly forces more gas seep into the coolant. High combustion temperature also requires more radiator performance, however, modern vehicle packaging only leaves very limited space for radiator installation. These limitations on radiator make the engine cooling system have very high internal flow resistance. All the factors mentioned above imply that the engine cooling system is going to have serious problems of water pump cavitation and coolant bubble flow if there is no deaeration system installed. The function of deaeration system is to continuously remove the gas from the engine coolant and avoid the water pump cavitation. This study has disclosed the mechanism of the water pump cavitation and coolant bubble flow, and their effects on the engine system.

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Huang, Chuan-Yi, i 黃川益. "A Study on Engine Cooling Controller System with BLDC Motor of Fuzzy Logic Technology". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/r54ex2.

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碩士
國立虎尾科技大學
機械與機電工程研究所
97
In this paper, the permanent magnet synchronous motor using fuzzy control technique in engine cooling system was studied. The engine cooling systems in a variety of types of vehicles use belt-driven fan mostly. Only cars and light goods vehicles use electric fan motors, but they are brush DC motors and use switch-mode control law; however, the fan output of two alternatives can not be adjusted with the cooling system at any time. The problem of excessively high current is also often one of the reasons that fans damage. Thus it increases the engine load, fuel consumption and the wear and tear of fan motor. Therefore, this paper replaces the traditional brush DC motors with permanent magnet synchronous motor for the engine cooling fan motors, and the water tank with water temperature is operated with intelligent fuzzy control theory. The program is inputted into C8051F330 by Silicon Laboritories companies Microcontroller MCU Development Tools. The output of the hardware builds simulation models. The simulation results showed that the application of engine cooling system using fuzzy theory maintained the stability to keep the best rotation rate of the engine. The use of permanent magnet synchronous motor with the water temperature fuzzy logic responses fast. It keeps the best temperature of the engine as well as decreases unnecessary operation of fan, reduces the wear and tear on the fan motor and improve life of cooling fan. This study can enhance performance and reduce fuel consumption in practice. Key Word：Permanent magnet;Brushless;Fuzzy

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鍾協智. "Design and Performance Tests of the Thermoelectric Generator System for the Waste Heat Recovery of Engine Water Cooling System". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/30513664516487245133.

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碩士
建國科技大學
機械工程系暨製造科技研究所
101
Based on the development of the thermoelectric technology, the applications and studies of the thermoelectric chip are more and more important. The heating and cooling sources in the engine of vehicle can be used to build the temperature gradient between the two side surfaces of the thermoelectric chip, and then the thermoelectric chip can generate the electric power. This studies proposed the high-performance heat absorber to be used in the thermoelectric conversion in the vehicle engine.; it would greatly increase the related performance. Several different configurations of heat absorbers have been designed. The objective of this work is to find the effect of the heat accumulation on the rapid absorption of the waste heat, and then combine the thermoelectric conversion technology to generate electricity. Finally, the critical technology of waste heat recovery can be obtained to serve as an important reference for designers and developers in the related vehicle and energy industries. Finally, The present work can be divided into three parts: (1) the parametric study of heat-transfer design for the thermoelectric generator system, (2) the fluid flow and heat transfer characteristics of pin-fin heat absorbers for thermoelectric conversion system, (3) the experimental study of thermoelectric generator system for waste heat recycling in cooling water of engine. The results indicate that the heat absorber of excellent heat transfer is not necessary in the design of the thermoelectric generator system. The heat absorber with the medium heat-transfer performance is good enough and economical.

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Lu, Yu-Jen, i 劉育任. "Using cooling system to promote the efficiency of applying thermoelectric generator on engine waste heat recovery". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/88059033070758997783.

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碩士
南台科技大學
機械工程系
97
Regarding the energy released from an internal combustion engine, there is almost 40% heat energy discharging to the environment through the exhaust pipe, and another 30% is consumed by the cooling system. The dispersed heat is more than the practical work done by the engine. This research investigates how to use cooling devices when driving the vehicle to improve the efficiency of applying thermoelectric generator (TEG) to recycle energy from the dispersed heat of exhaust pipe and radiator. During the performance tests of the TEG, the heat sink compound reveals positive effect and increases 10% output power. The pin fin tests also show 44% efficiency increasing effect. The simulation of pin fin indicates the shape affects the cooling outcome. The square pin fin results more stable effect. From the simulation of using deflector shows that, the surface temperature of exhaust pipe will be reduced from 137 ℃ to 131 ℃ after installation, which presents the cooling speed increasing effect. The output power from the waste heat recovered by the thermoelectric generator module can be improved by several methods. Applying the heat sink compound on the TEG will get 17% increment. Using the square pin fin can make 57% gains, and the air deflector can reach 10% increment. The results of experiments and simulations all indicate that, the cooling system is imperative for thermoelectric generator and has been proved useful.

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