Academic literature on the topic 'Thermo-hydraulic efficiency'
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Journal articles on the topic "Thermo-hydraulic efficiency"
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Smirnov, V. V., Yu V. Yavorovsky, V. V. Sennikov, and D. O. Romanov. "Comparative analysis of the efficiency of the application of thermal-hydraulic distributor with classical schemes of connecting subscribers." Vestnik IGEU, no. 3 (2019): 5–13. http://dx.doi.org/10.17588/2072-2672.2019.3.005-013.
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Analysis of the use of a thermo-hydraulic distributor in district heating schemes showed insufficient study of the mutual influence of the connected circuits, on which the coefficient of hydraulic stability of the heating network depends, and the lack of a comparative analysis of the efficiency of heat supply when using a scheme with a thermo-hydraulic distributor compared to widely used subscriber connection schemes. The purpose of the study is to compare the economic and energy efficiency of the proposed and existing subscriber connection schemes, which is an important task. In laboratory conditions, a wide range of studies have been carried out to study the hydraulic dependence of the contours of the thermo-hydraulic distributor among themselves. Processing of the results was carried out by the method of correlation-regression analysis and mathematical statistics. In a comparative analysis of subscriber connection schemes, methods of physical modeling of thermo-hydraulic modes were used. A comparative analysis showed that the energy efficiency of the scheme with a thermo-hydraulic distributor is higher in heating systems with non-automated subscribers, regardless of the temperature graph of the heating network. When comparing schemes with parallel connection of a hot water heater, it was found that the totality of electricity consumption for coolant circulation and fuel costs for a circuit with a thermo-hydraulic distributor turned out to be less irrespective of the temperature schedule. Statistical research methods confirmed the independence of the circuits and the normal supply of heat to the heating. New solutions have been obtained to increase the hydraulic stability of the centralized heat supply system using a thermo-hydraulic distributor at a heating point – the hydraulic stability coefficient of the heat network during all subscriber operation modes is equal to one. The results of the study can be used in the design of thermal points: the proposed heating system, the consumers of which will provide a stable hydraulic mode; existing heat supply system, the consumers of which must ensure the hydro-stable control of heat.
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Ketelsen, Søren, Sebastian Michel, Torben O. Andersen, Morten Kjeld Ebbesen, Jürgen Weber, and Lasse Schmidt. "Thermo-Hydraulic Modelling and Experimental Validation of an Electro-Hydraulic Compact Drive." Energies 14, no. 9 (April 22, 2021): 2375. http://dx.doi.org/10.3390/en14092375.
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Electro-hydraulic compact drives (ECDs) are an emerging technology for linear actuation in a wide range of applications. Especially within the low power range of 5–10 kW, the plug-and-play capability, good energy efficiency and small space requirements of ECDs render this technology a promising alternative to replace conventional valve-controlled linear drive solutions. In this power range, ECDs generally rely on passive cooling to keep oil and system temperatures within the tolerated range. When expanding the application range to larger power classes, passive cooling may not be sufficient. Research investigating the thermal behaviour of ECDs is limited but indeed required for a successful expansion of the application range. In order to obtain valuable insights into the thermal behaviour of ECDs, thermo-hydraulic simulation is an important tool. This may enable system design engineers to simulate thermal behaviour and thus develop proper thermal designs during the early design phase, especially if such models contain few parameters that can be determined with limited information available. Our paper presents a lumped thermo-hydraulic model derived from the conservation of mass and energy. The derived model was experimentally validated based on experimental data from an ECD prototype. Results show good accuracy between measured and simulated temperatures. Even a simple thermal model containing only a few thermal resistances may be sufficient to predict steady-state and transient temperatures with reasonable accuracy. The presented model may be used for further investigations into the thermal behaviour of ECDs and thus toward proper thermal designs required to expand the application range.
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Bhatter, Rahul Kumar, Ali Abbas, and Anant Kumar Rai. "Effect of Baffles Position on Thermo-Hydraulic Efficiency of a Solar Air Heater." IOP Conference Series: Materials Science and Engineering 1132, no. 1 (April 1, 2021): 012041. http://dx.doi.org/10.1088/1757-899x/1132/1/012041.
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Alam, Tabish, Md Irfanul Haque Siddiqui, Hassan Alshehri, Masood Ashraf Ali, Paolo Blecich, and Kushagra Saurabh. "Exergy-Based Thermo-Hydraulic Performance of Roughened Absorber in Solar Air Heater Duct." Applied Sciences 12, no. 3 (February 7, 2022): 1696. http://dx.doi.org/10.3390/app12031696.
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This paper presents the thermo-hydraulic performance of small conical ribs on the absorber plate of a solar energy air heater (SAH) using exergy analysis. Application of conical protrusion ribs on the absorber is an attractive solution for enhancing the thermal performance of a SAH. However, these ribs are also responsible for high friction losses and increased fan power consumption caused by the turbulent air flow. To optimize the rib design, it is vital to consider both thermal and hydraulic performance at the same time. The SAH was assessed using an analytic method which predicts the exergy efficiency under operating parameters (e.g., Reynolds number, solar insolation and temperature increase parameter). The following geometric quantities of ribs were evaluated for optimum exergy efficiency: the relative rib height (e/D), which was in the range between 0.200 and 0.044, and the relative rib pitch (p/e), which was in the range between 6 and 12. The combination of a relative rib height of 0.044 and relative rib pitch of 10 exhibits the highest exergy efficiency of 0.0202. The optimization of the rib geometric quantities parameters was performed by considering the temperature increase parameter, aiming to achieve maximum exergy efficiency. The combination of rib parameters e/D = 0.044 and p/e = 10 are noted to yield best performance when operating at a temperature increase parameter above 0.0141 K∙m2/W.
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Pugi, L., R. Conti, A. Rindi, and S. Rossin. "A Thermo-Hydraulic Tool for Automatic Virtual Hazop Evaluation." Metrology and Measurement Systems 21, no. 4 (December 1, 2014): 631–48. http://dx.doi.org/10.2478/mms-2014-0055.
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Abstract Development of complex lubrication systems in the Oil&Gas industry has reached high levels of competitiveness in terms of requested performances and reliability. In particular, the use of HazOp (acronym of Hazard and Operability) analysis represents a decisive factor to evaluate safety and reliability of plants. The HazOp analysis is a structured and systematic examination of a planned or existing operation in order to identify and evaluate problems that may represent risks to personnel or equipment. In particular, P&ID schemes (acronym of Piping and Instrument Diagram according to regulation in force ISO 14617) are used to evaluate the design of the plant in order to increase its safety and reliability in different operating conditions. The use of a simulation tool can drastically increase speed, efficiency and reliability of the design process. In this work, a tool, called TTH lib (acronym of Transient Thermal Hydraulic Library) for the 1-D simulation of thermal hydraulic plants is presented. The proposed tool is applied to the analysis of safety relevant components of compressor and pumping units, such as lubrication circuits. Opposed to the known commercial products, TTH lib has been customized in order to ease simulation of complex interactions with digital logic components and plant controllers including their sensors and measurement systems. In particular, the proposed tool is optimized for fixed step execution and fast prototyping of Real Time code both for testing and production purposes. TTH lib can be used as a standard SimScape-Simulink library of components optimized and specifically designed in accordance with the P&ID definitions. Finally, an automatic code generation procedure has been developed, so TTH simulation models can be directly assembled from the P&ID schemes and technical documentation including detailed informations of sensor and measurement system.
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Zhou, Aizhao, Xianwen Huang, Wei Wang, Pengming Jiang, and Xinwei Li. "Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections." Sustainability 13, no. 6 (March 16, 2021): 3255. http://dx.doi.org/10.3390/su13063255.
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For reducing the initial GSHP investment, the heat transfer efficiency of the borehole heat exchange (BHE) system can be enhanced to reduce the number or depth of drilling. This paper proposes a novel and simple BHE design by changing the cross-sectional shape of the U-tube to increase the heat transfer efficiency of BHEs. Specifically, in this study, we (1) verified the reliability of the three-dimensional numerical model based on the thermal response test (TRT) and (2) compared the inlet and outlet temperatures of the different U-tubes at 48 h under the premise of constant leg distance and fluid area. Referent to the circular tube, the increases in the heat exchange efficiencies of the curved oval tube, flat oval tube, semicircle tube, and sector tube were 13.0%, 19.1%, 9.4%, and 14.8%, respectively. (3) The heat flux heterogeneity of the tubes on the inlet and outlet sides of the BHE, in decreasing order, is flat oval, semicircle, curved oval, sector, and circle shapes. (4) The temperature heterogeneity of the borehole wall in the BHE in decreasing order is circle, sector, curved oval, flat oval, and semicircle shapes. (5) Under the premise of maximum leg distance, referent to the heat resistance of the tube with a circle shape at 48 h, the heat exchange efficiency of the curved oval, flat oval, semicircle, and sector tubes increased 12.6%, 17.7%, 10.3%, and 7.8%, respectively. (6) We found that the adjustments of the leg distance and the tube shape affect the heat resistance by about 25% and 12%, respectively. (7) The flat-oval-shaped tube at the maximum leg distance was found to be the best tube design for BHEs.
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Alam, Tabish, Chandan Swaroop Meena, Nagesh Babu Balam, Ashok Kumar, and Raffaello Cozzolino. "Thermo-Hydraulic Performance Characteristics and Optimization of Protrusion Rib Roughness in Solar Air Heater." Energies 14, no. 11 (May 28, 2021): 3159. http://dx.doi.org/10.3390/en14113159.
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To enhance the thermal performance of solar air heaters (SAHs), protrusion ribs on the absorber are considered to be an attractive solution due to their several advantages. These ribs do not cause a significant pressure drop in the SAH duct and help to enhance the heat transfer to flowing air. On the other hand, a degree of roughness of the protrusion rib on the absorber can be produced by pressing the indenting device without adding additional mass. In this paper, the thermo-hydraulic performances of different roughnesses of the conical protrusion rib on the absorber plate have been evaluated by the mutual consideration of thermal as well as hydraulic performance in term of net effective efficiency. Therefore, an analytical technique has been exploited to predict the characteristics of the net effective efficiency under various operating conditions, such as the flow Reynolds number, temperature increase parameter and insolation. The effects of the conical protrusion rib roughness—namely the relative rib pitch (p/e) and relative rib height e/D) in the ranges of 6–12 and 0.200–0.044, respectively—have been evaluated. The highest value of net effective efficiency of 70.92% was achieved at a p/e of 10 and e/D of 0.0289. The optimization of the rib parameters has been carried out in different ranges of temperature increase parameters for the highest values of net effective efficiency. A unique combination of rib parameters—a p/e of 10 and e/D of 0.044—are observed to lead to the best performance when operating a solar air heater with a temperature increase parameter of more than 0.00789 K·m2/W.
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Singh, Niranjan Ramendra, Singh Onkar, and Janakarajan Ramkumar. "Thermo-Hydraulic Performance of Square Micro Pin Fins under Forced Convection." International Journal of Heat and Technology 39, no. 1 (February 28, 2021): 170–78. http://dx.doi.org/10.18280/ijht.390118.
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Thermal management of the new generation’s high performance electronic and mechanical devices is becoming important due to their miniaturization. Conventionally, the plate fin arrangement is widely used for removal of dissipated heat but, their effectiveness is not up to mark. Among different options, the most attractive and efficient alternative for overcoming this problem is micro pin fin heat sink. This paper presents the experimental investigation of square micro-pin fins heat sink for identifying the most suitable pin fin geometry for heat removal applications under forced convection. Twenty five square micro pin fin heat sinks were tested for three different heat load and Reynolds number. The results show that for large fin height lower thermal resistance was observed at the cost of large pressure drop. The dimensionless heat transfer coefficient increases with fin height and Reynolds number while it decreases with increasing fin spacing. The improvement in micro pin fin efficiency were observed by about 2 to 9% owing to presence of fins on the impingement surface, flow mixing, disruption of the boundary layers, and augmentation of turbulent transport.
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Borek, Kinga. "Influence of liquid-nitrogen freezing of gas-bearing shale rocks on their compressive strength." Mineralogia 49, no. 1-4 (December 1, 2018): 7–16. http://dx.doi.org/10.2478/mipo-2018-0002.
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Abstract Any definable relation between falling temperature and the compressive strength of shale rocks should provide a useful predictive tool aiding optimization of the results of hydraulic fracturing. In this research, an automeasuring hydraulic press, a thermo-camera and the Fluent ANSYS software were used. The results of laboratory simulations, and the effects of experiments conducted on shale rocks to determine permanent changes in compressive strength, are presented. As both frozen rocks and rocks returned to room temperature show diminished compressive strength. It is suggested that prior freezing of rocks can increase the efficiency of fracturing.
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Barreto, Germilly, Paulo Canhoto, and Manuel Collares-Pereira. "Effect of thickness on the thermo-hydraulic performance of porous volumetric solar receivers with different internal geometries." Journal of Physics: Conference Series 2116, no. 1 (November 1, 2021): 012116. http://dx.doi.org/10.1088/1742-6596/2116/1/012116.
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Abstract In this work, the effect of thickness on the thermal and hydrodynamic performance of porous volumetric solar receivers made of open-cell silicon carbide (SiC) ceramic foam is investigated using an in-house detailed numerical model. The model is based in a Computational Fluid Dynamics (CFD) technique to solve the volume averaged mass, momentum and energy conservation equations, including the exchange of thermal radiation inside the receiver. A Monte Carlo Ray Tracing (MCRT) method was developed and then used to model the solar radiation transport in the porous media. Two optimised internal geometries (porosity and pores size) of the receiver with adiabatic side-walls are investigated for different thicknesses. Results show that the optimal thickness depends on the porosity and pores size and there is a value from which the thermal efficiency is nearly constant and the pressure drop always increase. It was also found that the thickness should be approximately between 5 and 7 cm for porosity and pores diameter between 0.85 and 0.90 and 3.0 mm and 4.5 mm, respectively, aiming to maximise thermal efficiency by decreasing the transmission losses of solar radiation, and to keep low pressure drop.
Dissertations / Theses on the topic "Thermo-hydraulic efficiency"
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Мейріс, Антон Жанович. "Теплообмін та теплогідравлічна ефективність пучків труб з поверхневими заглибленнями." Thesis, Інститут технічної теплофізики НАН України, 2018. https://ela.kpi.ua/handle/123456789/38181.
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Робота виконана в Національному технічному університеті України «Київський політехнічний інститут імені Ігоря Сікорського» МОН України на кафедрі фізики енергетичних систем і в Інституті технічної теплофізики НАН України у відділі високотемпературної термогазодинаміки. Захищена в Інституті технічної теплофізики НАН України.Дисертація присвячена експериментальному та теоретичному дослідженню теплообміну та гідродинаміки при поперечному обтіканні одиночної труби та пучку труб із поверхневими заглибленнями. Теоретично досліджено теплообмін та гідродинаміку при поперечному обтіканні одиночної труби із поверхневими заглибленнями у формі усіченого конусу за допомогою комп’ютерного пакету ANSYS CFX. Проведено верифікацію моделей турбулентності. Наведено результати досліджень вихрової структури потоку, точки відриву потоку, зони зворотних течій, коефіцієнту лобового опору, коефіцієнту теплообміну. Проведено експериментальні та теоретичні дослідження теплообміну та гідродинаміки при поперечному обтіканні п’ятирядного пучку труб із поверхневими заглибленнями. Отримані дані щодо коефіцієнтів гідравлічного опору пучка та коефіцієнтів теплообміну по рядах та для пучка в цілому. Проведено верифікацію комп’ютерної моделі по експериментальним даним. Розроблено інженерну методику розрахунку рекуператора газотурбінної установки та проведено оцінку зниження його маси за рахунок нанесення заглиблень.
The dissertation is devoted to the experimental and theoretical study of heat transfer and hydrodynamics at the cross-flow of a single tube and a tube bundle with surface indentations. Heat transfer and hydrodynamics were studied theoretically at the cross-flow of a single tube with surface indentations in the form of a truncated cone using the ANSYS CFX computer package. Verification of turbulence models is carried out. The results of studies of the vortex structure of the flow, the point of separation of the flow, the zone of reverse flows, the coefficient of the frontal resistance, and the heat transfer coefficient are given. Experimental and theoretical investigations of heat transfer and hydrodynamics are carried out at the cross-flow of a five-row tube bundle with surface indentations. The data on the coefficients of the hydraulic resistance of the bundle and of the heat transfer coefficients for rows and for the whole bundle are obtained. Verification of the computer model by experimental data is carried out. An engineering method for calculation of the gas turbine plant recuperator was developed and an estimation of the decrease in its mass due to the application of depressions was made.
Conference papers on the topic "Thermo-hydraulic efficiency"
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Nakashima, Celso Y., Silvio Oliveira, and Elisio F. Caetano. "Thermo-Hydraulic Model of a Twin-Screw Multiphase Pump." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60139.
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The twin-screw multiphase pump has been studied as an alternative equipment to substitute the conventional system (fluid separation, liquid pumping and gas compression) in petroleum boosting. By “pumping” gas and liquid together, the multiphase pump could reduce production costs, particularly in deepwater activity. This paper presents a thermo-hydraulic model of a twin-screw multiphase pump developed to determine important parameters such as: volumetric efficiency, absorbed power, discharge conditions, heat transfer and pressure and temperature profiles. The continuous movement from suction to the discharge of pump chambers is divided in small discretive steps. This division allows the calculation of energy and mass balances for each screw chamber. At each step, it is possible to calculate mass and energy that enters and leaves one chamber. With this balance, pressure and temperature for the next step can be calculated. Differently from previous model, it considers not only water-air but also hydrocarbon mixtures (including petroleum heavy fractions) as working fluids. Besides, inclusion of screw rotation influence over peripheral backflow is not neglected as in previous models.
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Virt, Vitaly, Vladimir Kosolapov, Vener Nagimov, Andrey Salamatin, Yulia Fesina, Anastasia Alekseeva, Yulia Yakhina, and Elizaveta Skutina. "Individual Fracture Efficiency Monitoring in Horizontal Wells by Using a New 3d Fine-Grid Temperature Modelling." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207237-ms.
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Abstract Profitable development of hard-to-recover reserves often involves drilling of horizontal wells with multistage hydraulic fracturing to increase the oil recovery factor. Usually to monitor the fracture sweep efficiency, pressure transient analysis is used. However, in case of several fractures this method delivers only average hydrodynamic parameters of the well-fracture system. This paper illustrates the value of temperature logging data and demonstrates possibilities of the 3-D thermo-mechanical modelling in evaluating the differential efficiency of multi-stage hydraulic fracturing.
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Karlén, Niko, Tatiana Minav, and Matti Pietola. "Investigation of Thermal Effects in Direct Driven Hydraulic System for Off-Road Machinery." In 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1512.
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Several types of off-road machinery, such as industrial trucks, forklifts, excavators, mobile cranes, and wheel loaders, are set to be operated in environments which can differ considerably from each other. This sets certain limits for both the drive transmissions and working hydraulics of these machines. The ambient temperature must be taken into account when selecting the hydraulic fluid since the viscosity and density of the fluid are changing at different operating temperatures. In addition to the temperature, energy efficiency can also be a problem in off-road machinery. In most off-road machines, diesel engines are employed to produce mechanical energy. However, there are energy losses during the working process, which causes inefficiency in produced energy. For better energy efficiency, hybridization in off-road machinery is an effective method to decrease fuel consumption and increase energy savings. One of the possible methods to save energy with hybrids is energy regeneration. However, it means that the basic hydraulic system inside off-road machinery needs to be modified. One solution for this is to utilize zonal or decentralized approach by means of direct driven hydraulic (DDH) system. This paper aims to investigate a DDH system for off-road machinery by means of modelling and analyzing the effect of the temperature. In the direct-driven hydraulic system, the actuator is controlled directly by the hydraulic pump which is operated by the electric motor. Specifically, it is a valveless closed-loop hydraulic system. Thus, there will be no energy losses caused by the valves, and the total efficiency is assumed to be significantly higher. In order to examine the DDH system, a thermo-hydraulic model was created. Additionally, a thermal camera was utilized in order to illustrate the temperature changes in the components of the DDH system. To reproduce the action of the system in different circumstances DDH system was run at different ambient temperatures, and the component temperatures in the system were measured and saved for the analysis. The thermo hydraulic model was proven capable to follow the general trend of heating up.
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Li, Bing, Samuel D. Marshall, Rerngchai Arayanarakool, Lakshmi Balasubramaniam, Poh Seng Lee, and Peter C. Y. Chen. "Study of Performance Impact by Thermo-Hydraulic Developing Entrance in Spiral Microchannel With CFD Analysis." In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6408.
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Microchannel heat exchangers have become widely employed in modern systems, found within aerospace applications, waste heat recovery, water treatment processes, air conditioning, biomedical treatments and various industrial process applications. The microchannels increase the ratio of heat transfer surface to volume, thus improving the heat transfer performance significantly whilst reducing the overall weight and size. Moreover, by utilizing secondary flow from Dean Vortices induced by curved microfluidic channels, the fluid flow and heat transfer performance can be enhanced even further beyond conventional straight channels. However, since pressure drops found in microchannels are often quite high, channel lengths must be kept relatively short to balance the friction loss and energy consumption. Due to this, the developing region length at the microchannel entrance area has a greater impact than for macroscale channels, in terms of hydrodynamic and thermal performance over the remaining full developed region. The thermo-hydraulic design for heat transfer microchannel surfaces is strongly dependent on several dimensionless performance indicators, namely Nusselt number ‘Nu’ for heat transfer, and Poiseuille number ‘Po’, which is the product of Fanning friction factor ‘f’ and Reynolds number ‘Re’. These parameters are used to characterize and optimize the performance of microchannel surfaces and heat exchangers in general, also can be used to determine both the thermal and hydraulic developing region lengths at the channel entrance area. Whilst many such studies exist for theoretical analysis and experimental verifications, currently there is little literature on the developing region lengths and impacts researched through the method of Computational Fluid Dynamics (CFD). As such, this paper identifies and explores via quantitative analysis the hydraulic and thermal performance changes created by the relevant developing region lengths at the entrance area of spiral microchannels, as well as determinations and comparisons of these effects over straight channels. The numerical results, generated via COMSOL Multiphysics and contrasted with previous literature on the subject, also compared with the effect of the developing region on the effectiveness and efficiency of both spiral and straight microchannels, finding an improved heat transfer performance but an increased impact of hydraulic friction as well for spiral channels against straight counterpart. Furthermore, significant differences between thermal developing region length and hydraulic developing region length can be observed throughout, which illustrates high challenge and the need for compromise in microchannel design. In this way, implications for the configuration and design of industrial microchannels and micro heat exchangers are self-evident. All the key factors given in this paper are dimensionless, and thus the generated results can be utilized for a variety of flow conditions. Hence, this work should permit an increased understanding for and boost the curved microchannel and micro heat exchanger designs subsequently, through reducing the required numbers of tests and experiments and expediting the development for similar applications followed.
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Cheng, Jie, Yingwei Wu, G. H. Su, Suizheng Qiu, and Wenxi Tian. "Neutronics and Thermo-Hydraulic Analysis of Water-Cooled Blanket Based on PWR and SCWR Water Conditions for CFETR." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60392.
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China Fusion Engineering Test Reactor (CFETR) is a test tokamak reactor being designed in China to bridge the gap between ITER and future fusion power plant. As one of the candidates, a water-cooled solid breeder blanket based on PWR (pressurized water reactor) and SCWR (super-critical water reactor) water conditions were proposed. In the concept, multiplying layers separated by three breeding layers were designed and optimized for higher Tritium Breeding Ratio (TBR) and uniform heat distribution. This blanket uses the Li2TiO3 lithium ceramic pebbles as the breeder, while beryllium pebbles as the neutron multiplier. In this paper, the thermal and fluid dynamic analyses of the optimized blanket on both water conditions were performed by numerical simulation, to discuss thermo-hydraulic performance of the blanket using pressurized water/supercritical water as its coolant. The nuclear heating distribution was obtained from the neutronics calculations by MCNP. The thermal hydraulic behaviors of the first wall (FW), structure material, Li2TiO3 pebble bed and Beryllium pebble bed under normal condition were calculated, respectively. It was found that the temperature on the blanket can be effectively cooled on both water conditions, certified the feasibility of the blanket design with pressurized/supercritical water cooling scheme. It indicated that SCWR case had smaller safety margin than PWR case, but SCWR case would lead higher outlet temperature, thermal conductivity and heat exchange efficiency also. In addition, it was found that beryllium was the dominant factor leading a higher TBR. The results would be important to water condition choice for solid blanket in the future.
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Polanský, Jiří, and Roman Gášpár. "Optimization of the Thermodynamics Cycles of Generation IV Gas-Cooled Fast Reactors." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64565.
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This paper deals with the thermo-hydraulic properties of Generation IV Gas Cooled Fast Reactors. The paper is focused on the comparison of direct and indirect thermodynamic cycles of helium cooled reactors from a thermodynamic point of view. The calculation includes pressure losses at all major parts of the equipment — reactor, heat exchangers, pipe lines, etc. The compressor and the gas turbine efficiencies are included in calculation as well. The working fluid used in the primary circuit is helium. In the secondary circuit a mixture of helium and nitrogen is used. The cycle characteristic point and efficiency calculation reflects mixture properties of the real gas — especially for N2. Calculations point out the influence of the mixture composition on the basic structural parameters of the turbines, compressors and heat exchangers. Thermodynamic cycle efficiency, specific heat input/output, heat flux and cycle work will be presented as characteristic parameters.
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Johansen, Per, Daniel B. Roemer, Torben O. Andersen, and Henrik C. Pedersen. "Analysis of the Thermo-Viscous Effect on Friction and Energy Dissipation in Oil Lubricated Interfaces." In 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1554.
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The last decade an increasing amount of work are performed with the aim of enhancing efficiency and reliability of fluid power components. Consequently, the loss mechanisms of lubricated tribological interfaces are of particular interest. This has led to development of sophisticated three-dimensional thermo-elasto-hydrodynamic lubrication models of fluid power components. The computational efforts involved in simulation with such models entail that design optimization are to some extend impractical. However, such models are also pursued in theoretical tribology with the aim to study loss and wear mechanisms, which is very difficult to study experimentally. In consequence, advanced numerical models are the state of the art approach in theoretical fluid power tribology research. However, a downside of modern numerical models is the inability to provide a practical tool for wide-scale parameter sweep investigations, due to computational effort, whereby analytical research in loss mechanisms still have certain advantages. In this paper, the thermo-viscous effect of a lubricant is included in an analytical study of the friction and energy dissipation of oil hydraulic thin-films. This analytical study is based on an asymptotic approximation of the laminar lubrication thermal field at low reduced Peclet and Brinkman number, where viscosity is included as a function of temperature. The asymptotic series is truncated at first order and used to derive an expression of the viscous friction on a sliding surface. This reveal an influence from the surface temperature gradient on the viscous friction, which is not revealed when applying classical isothermal analysis. The significance of the thermo-viscous effect on friction and energy dissipation is analyzed analytically in order to provide a qualitative insight to the relation between thermodynamic properties, film thickness, sliding velocity and viscous friction.
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Riedel, Christian, Christian Stammen, and H. Murrenhoff. "Fundamentals of Mass Conservative System Simulation in Fluid Power." In ASME 2009 Dynamic Systems and Control Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/dscc2009-2639.
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This article illustrates the development of a dynamic system simulation tool for fluid power on basis of mass flows. The goal is to increase the predictability and efficiency of system simulation tools in fluid power. State of the art simulation tools make use of simplified differential equations. Especially in closed systems or long-term simulations, the volume flow based approach leads to significant variations of simulation results as balancing of flow parameters and its integrations to potentials lead to a violation of the equation of continuity. However, with a mass flow and energy conservative approach we obtain a clear and physically correct model implemented in the simulation tool DSHplus. The new basis of calculation enables further implementation of thermo-hydraulic and multi-phase flow models such as cavitation or particle transport into the concentrated parametric system simulation.
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Nasrabadi, Mehdi, and Ramin Haghighi Khoshkhoo. "Design of Fin Plate Heat Exchanger for Increasing Micro Turbine Efficiency and Introduction of Fin Plate Heat Exchanger Design Software (KhoshNasr) for this Purpose." In ASME 2008 Heat Transfer Summer Conference collocated with the Fluids Engineering, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/ht2008-56114.
Full textAbstract:
A heat exchanger is a part of micro turbines, which can improve thermal efficiency of micro turbines up to 30 percent. Some important factors in design of heat exchangers are low cost, high efficiency, small size, low weight and high performance. In this paper, design of a heat exchanger with consideration of Iranian industry’s capability has been investigated. A survey of different types of gas to-gas heat exchangers is presented and then fin-tube heat exchanger, fin-plate heat exchanger, shell & tube heat exchanger and regenerator are designed. Also, the effect of thermo hydraulic parameters on the efficiency of the three heat exchangers is investigated. Effects of these heat exchangers on the efficiency of a 100 kW micro turbine are studied and the heat exchanger with the highest efficiency is selected. The algorithm for design and modeling of the selected heat exchanger is then presented. After research on all types of heat exchangers, fin plate heat exchanger appeared to be the optimum choice for manufacturing in Iran industry. A new design program was written in MATLAB based on our suggested algorithm. Since there were some practical charts about heat transfer and pressure drop in design of the heat exchanger, all the existing experimental curves related to heat transfer and pressure of fins (required in the design of the heat exchanger) were converted to data (using “Image Processing” technique in MATLAB) and implemented in the design program.
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Johansen, Per, Daniel B. Roemer, Torben O. Andersen, and Henrik C. Pedersen. "Multibody Dynamics of a Fluid Power Radial Piston Motor Including Transient Hydrodynamic Pressure Models in Lubricating Gaps." In ASME/BATH 2013 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fpmc2013-4462.
Full textAbstract:
The increasing interest in hydraulic transmissions in wind and wave energy applications has created an incentive for the development of high efficiency fluid power machinery. Modeling and analysis of fluid power machinery loss mechanisms are necessary in order to accommodate this demand. At present fully coupled thermo-elastic models has been used to simulate and study loss mechanisms in various tribological interfaces. Consequently, a reasonable focus of further development is to couple the interface models and the rigid body mechanics of fluid power machinery. The focus of the current paper is a multibody dynamics model of a radial piston fluid power motor, which connects the rigid bodies through models of the transient hydrodynamic lubrication pressure in the joint clearance. A finite volume approach is used to model the pressure dynamics of the fluid film lubrication. The model structure and model equations are explained in this paper and simulation results are shown in terms macroscopic and microscopic dynamics.