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Статті в журналах з теми "Thermal hydraulic drive"
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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.
Повний текст джерелаАнотація:
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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Konev, V. V. "Evaluation of the trailbuilder hydraulic drive thermal preparation." IOP Conference Series: Materials Science and Engineering 1103, no. 1 (March 1, 2021): 012015. http://dx.doi.org/10.1088/1757-899x/1103/1/012015.
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Kulikov, Ilya, Kirill Karpukhin, and Rinat Kurmaev. "X-in-the-Loop Testing of a Thermal Management System Intended for an Electric Vehicle with In-Wheel Motors." Energies 13, no. 23 (December 6, 2020): 6452. http://dx.doi.org/10.3390/en13236452.
Повний текст джерелаАнотація:
The article describes an elaboration of the X-in-the-loop (XiL) testing environment for a thermal management system (TMS) intended for the traction electric drive of an electric vehicle, which has each of its wheels driven by an in-wheel motor. The TMS features the individual thermal regulation of each electric drive using a hydraulic layout with parallel pipelines and electrohydraulic pumps embedded into them. The XiL system is intended as a tool for studying and developing the TMS design and controls. It consists of the virtual part and the physical part. The former simulates the vehicle operating in a driving cycle with the heat power dissipated by the electric drive components, which entails the change in their temperature regimes. The physical part includes the TMS itself consisting of a radiator, pipelines, and pumps. The physical part also features devices intended for simulation of the electric drive components in terms of their thermal and hydraulic behaviors, as well as devices that simulate airflow induced by the vehicle motion. Bilateral, real-time interactions are established between the two said parts combining them into a cohesive system, which models the studied electric vehicle and its components. The article gives a description of a laboratory setup, which implements the XiL environment including the mathematical models, hardware devices, as well as the control loops that establish the interaction of those components. An example of using this system in a driving cycle test shows the interaction between its parts and operation of the TMS in conditions simulated in both virtual and physical domains. The results constitute calculated and measured quantities including vehicle speed, operating parameters of the electric drives, coolant and air flow rates, and temperatures of the system components.
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Latynin, Andrej, Andrej SHvyryov, Irina Kondratenko, and Irina Andrejshcheva. "FEATURES OF THERMAL DIAGNOSIS METHOD FOR HYDROSTATIC TRANSMISSION OF FOREST MACHINES." Voronezh Scientific-Technical Bulletin 2, no. 2 (January 25, 2022): 42–49. http://dx.doi.org/10.34220/2311-8873-2022-42-49.
Повний текст джерелаАнотація:
The extraction of timber in the territory of the Russian Federation is carried out mainly by logging technical complexes, made on the basis of machines with a hydraulic drive. In turn, of the currently known types of hydrodynamic transmission, the most advanced is the hydro-static transmission. Despite the exceptional reliability of such equipment, hydrodynamic transmission, including hydrostatic transmis-sion, has a large number of failures. The main hydrostatic transmission failures include mal-functions of the wheel drive hydraulic motor. Therefore, the purpose of this study is to use the method of thermal diagnostics to reduce the number of failures in hydrodynamic transmission, including hydrostatic transmis-sion.
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Suslov, N. M., S. Ya Davydov, D. N. Suslov, S. A. Chernukhin, and V. S. Velikanov. "Thermal calculation of the hydraulic drive of the dragline walking mechanism." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 12 (January 23, 2020): 10–12. http://dx.doi.org/10.17073/1683-4518-2019-12-10-12.
Повний текст джерелаАнотація:
A new device for moving walking machines is proposed. It allows you to reduce energy consumption for the movement of the dragline by eliminating the friction of the support base on the ground while maintaining the step size and providing a given direction of its movement. The thermotechnical calculation for the hydraulic dragline walking mechanism is presented with the aim of using the heat generated during the dragline movement to heat the driver’s cab during overburden operations at low ambient temperatures. Ill. 1, Ref. 10. Tab. 1.
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Suslov, N. M., S. Ya Davydov, D. N. Suslov, S. A. Chernukhin, and V. S. Velikanov. "Thermal Calculation of the Hydraulic Drive for a Dragline Walking Mechanism." Refractories and Industrial Ceramics 60, no. 6 (March 2020): 558–60. http://dx.doi.org/10.1007/s11148-020-00406-2.
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Wang, Haifei, Shimin Yang, and Tan Lu. "Mechanical transmission system of loader based on hydraulic hybrid technology." Thermal Science 25, no. 6 Part A (2021): 4233–40. http://dx.doi.org/10.2298/tsci2106233w.
Повний текст джерелаАнотація:
In order to solve the problems of high energy consumption, high noise and pollution gas emission existing in the mechanical transmission system of loader, a research on the mechanical transmission system of loader based on hydraulic hybrid technology is proposed. The mechanical energy and heat energy are generated by the mechanical operation of the loader, which are converted into hydraulic energy and output to the drive system. According to the fast response characteristics and high power density characteristics of the hydraulic power system relative to the thermal engine, the dynamic model of the hydraulic hybrid drive system of the loader is established. The double fuzzy PID control method is used to identify and modify the unknown load and power parameters of the drive system. Through the experiment, it is concluded that the power parameter matching of the transmission system using the hydraulic hybrid technology is more optimized, the application effect is good, and the efficiency of the power transmission system can be maximized.
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Ketelsen, Søren, Damiano Padovani, Torben Andersen, Morten Ebbesen, and Lasse Schmidt. "Classification and Review of Pump-Controlled Differential Cylinder Drives." Energies 12, no. 7 (April 4, 2019): 1293. http://dx.doi.org/10.3390/en12071293.
Повний текст джерелаАнотація:
Pump-controlled hydraulic cylinder drives may offer improved energy efficiency, compactness, and plug-and-play installation compared to conventional valve-controlled hydraulic systems and thus have the potential of replacing conventional hydraulic systems as well as electro-mechanical alternatives. Since the late 1980s, research into how to configure the hydraulic circuit of pump-controlled cylinder drives has been ongoing, especially in terms of compensating the uneven flow requirements required by a differential cylinder. Recently, research has also focused on other aspects such as replacing a vented oil tank with a small-volume pressurized accumulator including the consequences of this in terms of thermal behavior. Numerous references describe the advantages and shortcomings of pump-controlled cylinder drives compared to conventional hydraulic systems or electro-mechanical drives. This paper presents a throughout literature review starting from the earliest concepts based on variable-displacement hydraulic pumps and vented reservoirs to newer concepts based on variable-speed electric drives and sealed reservoirs. By classifying these drives into several proposed classes it is found that the architectures considered in the literature reduce to a few basic layouts. Finally, the paper compares the advantages and shortcomings of each drive class and seek to predict future research tasks related to pump-controlled cylinder drives.
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Jasiński, Ryszard. "Problems of the Starting and Operating of Hydraulic Components and Systems in Low Ambient Temperature (Part V)." Polish Maritime Research 24, no. 4 (December 20, 2017): 47–56. http://dx.doi.org/10.1515/pomr-2017-0135.
Повний текст джерелаАнотація:
Abstract A large number of hydraulic devices and systems are started in low ambient temperatures. A good example of such a device is the hoisting winch on the ship. Starting hydraulic drive units in thermal shock conditions (rapid supply of hot oil to the cold unit) may lead to incorrect operation of the actuating system, for instance, due to the loss of clearance between cooperating elements. The article presents methods to prevent the disappearance of effective clearance in a hydraulic motor started in thermal shock conditions. For this reason, the structure of the hydraulic satellite motor was complemented by elements creating special channels through which hot oil could flow and additionally heat fixed parts of the motor. This solution ensures faster heating of motor housing, thus decreasing the temperature difference between the housing and the satellites during motor start-up in thermal shock conditions.
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Vanin, V., and M. Kruhol. "HYDRAULIC MODELS IN THE PROBLEMS OF THERMAL POWER PLANT AUXILIARY ENERGY EFFICIENCY IMPROVEMENT." Journal of Numerical and Applied Mathematics, no. 1 (135) (2021): 36–42. http://dx.doi.org/10.17721/2706-9699.2021.1.04.
Повний текст джерелаАнотація:
The work is devoted to the study of thermal power plants auxiliary energy efficiency. The main mechanisms in the auxiliary systems are centrifugal mechanisms that work in complex hydraulic networks with variable productivity. The main ways to adjust the parameters of the centrifugal mechanisms are to change the speed of rotor rotation, change the guide vane angle and throttle. The operation mode of a complex hydraulic network which includes a group of centrifugal mechanisms with a mixed connection scheme is analyzed. The system of equations which characterize the hydraulic system has been obtained on the basis of Kirchhoff's laws. The centrifugal mechanisms' operating characteristics are given by approximation dependences obtained with the method of least squares and similarity laws. To analyze efficiency of different methods of centrifugal mechanisms parameters regulation, optimal control problems were set and solved. The constraints for the problems are a system of equations that describe the hydraulic system operation and technical constraints that depend on the control method. Through solving the problems, values of the optimal parameters and weighted average efficiency of the group mechanisms were obtained. Studies have shown that the most effective way to regulate the centrifugal mechanisms parameters is to use an individual frequency drive, the least effective is to use only changing angle of centrifugal mechanism's guide vane. Utilization of group control is highly efficient and not inferior to individual frequency drive. However, this statement is correct under condition of the operating characteristics agreement with the centrifugal mechanisms’ operating modes similarity.
Дисертації з теми "Thermal hydraulic drive"
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Lammers, Zachary A. "Thermal Management of Electromechanical Actuation System for Aircraft Primary Flight Control Surfaces." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1399021324.
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Бєліков, Костянтин Олександрович. "Теплогідравлічний слідкуючий привод позиціонування приймача геліостанції". Doctoral thesis, Київ, 2016. https://ela.kpi.ua/handle/123456789/18264.
Повний текст джерелаАнотація:
Дисертація присвячена теоретичним та експериментальним дослідженням, спрямованим на створення приводів позиціонування приймачів геліостанцій на основі теплового розширення рідин. Розглянуто варіанти виконання слідкуючих приводів і систем позиціонування сонячних панелей і теплових колекторів, визначені основні фактори впливу на роботу приводів позиціонування, особливості функціонування та вплив умов експлуатації на їх характеристики. Запропоновано технічне рішення багатомодульного теплового гідроприводу позиціонування приймача геліостанції, робота якого базується на використанні рідин з високим коефіцієнтом теплового розширення. Розроблено узагальнену математичну модель дії теплогідравлічного модуля та проведено теоретичне дослідження впливу основних факторів на вихідні характеристики. Отримані прогнозовані характеристики теплогідравлічного модуля з урахуванням зміни рівня потоку інсоляції, конструктивних параметрів приводу та умов експлуатації. Проведено експериментальні дослідження теплогідравлічного модуля та виконано порівняльний аналіз характеристик отриманих при модельних та натурних експериментах. На основі результатів модельних та експериментальних досліджень теплового гідроприводу запропоновано інженерну методику розрахунку багатомодульного теплового гідроприводу позиціонування приймача геліостанції. Встановлено діапазон раціональних значень основних параметрів теплового гідроприводу. Результати роботи впроваджено для використання при проектуванні геліостанцій в Інституті відновлювальної енергетики НАН України та в навчальному процесі НТУУ «КПІ».
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Minav, Tatiana, Luca Papini, and Matti Pietola. "A Thermal Analysis of Direct Driven Hydraulics." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200125.
Повний текст джерелаАнотація:
This paper focuses on thermal analysis of a direct driven hydraulic setup (DDH). DDH combines the benefits of electric with hydraulic technology in compact package with high power density, high performance and good controllability. DDH enables for reduction of parasitic losses for better fuel efficiency and lower operating costs. This one-piece housing design delivers system simplicity and lowers both installation and maintenance costs. Advantages of the presented architecture are the reduced hydraulic tubing and the amount of potential leakage points. The prediction of the thermal behavior and its management represents an open challenge for the system as temperature is a determinant parameter in terms of performance, lifespan and safety. Therefore, the electro-hydraulic model of a DDH involving a variable motor speed, fixed-displacement internal gear pump/motors was developed at system level for thermal analysis. In addition, a generic model was proposed for the electric machine, energy losses dependent on velocity, torque and temperature was validated by measurements under various operative conditions. Results of model investigation predict ricing of temperature during lifting cycle, and flattened during lowering in pimp/motor. Conclusions are drawn concerning the DDH thermal behavior.
Частини книг з теми "Thermal hydraulic drive"
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Zohuri, Bahman. "Combined Cycle-Driven Efficiency in Nuclear Power Plant." In Thermal-Hydraulic Analysis of Nuclear Reactors, 523–52. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53829-7_16.
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Zohuri, Bahman. "Heat Transport System Thermal Hydraulics." In Combined Cycle Driven Efficiency for Next Generation Nuclear Power Plants, 61–85. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15560-9_4.
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Zohuri, Bahman, and Patrick McDaniel. "Heat Transport System Thermal Hydraulics." In Combined Cycle Driven Efficiency for Next Generation Nuclear Power Plants, 59–83. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-70551-4_4.
Повний текст джерелаТези доповідей конференцій з теми "Thermal hydraulic drive"
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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.
Повний текст джерелаАнотація:
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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Chen, Ning. "Special Electro-Hydraulic Valve for Hydro-Viscous Drive Used in Thermal Power Generation Plant." In 2009 Asia-Pacific Power and Energy Engineering Conference. IEEE, 2009. http://dx.doi.org/10.1109/appeec.2009.4918777.
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Frick, Peyton, Hany Bassily, Heather Watson, and John Wagner. "A Hydraulic Fan Driven Heat Exchanger for Automotive Cooling Systems." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13464.
Повний текст джерелаАнотація:
Hydraulics are widely applied in transportation and manufacturing systems due to their high power density, design flexibility for power transmission, and ease of computer control. One fluid system application that merits investigation is the internal combustion engine advanced thermal management system which replaces the traditional mechanical coolant pump and radiator fan with computer controlled components. Although electric servo-motors may be integrated to drive these mechanical loads, the power demands often require large actuator sizes and electrical currents. An alternative to dc motors are hydraulic driven motors which offer higher torques in a smaller package space. In the paper, an automotive heat exchanger will be investigated that features a computer controlled hydraulic actuated fan. A series of dynamic models will be presented for the radiator, fan assembly, and hydraulic circuit. For comparison purposes, two radiator models are developed using heat transfer concepts for a cross flow heat exchanger. The ε-NTU method is a standard methodology for heat exchanger analysis involving a logarithmic mean temperature difference of the fluids. In contrast, the Nusselt method uses temperature differential equations for fluids in cross flow to calculate an average temperature difference. Representative numerical results will be presented to demonstrate transient responses of the hydraulic components as well as the radiator temperature.
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Liu, Qian-feng, and Han-liang Bo. "Thermal Analysis of the Head of the Direct Action Solenoid Valve." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15555.
Повний текст джерелаАнотація:
Hydraulic Control Rod Drive Technology (HCRDT) is a newly invented patent and Institute of Nuclear and New Energy Technology Tsinghua University owns HCRDT’s independent intellectual property rights. The Integrated valve which is made up of three direct action solenoid valves is the key part of this technology, so the performance of the solenoid valve directly affects the function of the integrated valve and the HCRDT. On one hand, based on the conditions occurring in the operation of the Control Rod Hydraulic Drive System, the thermal characteristics of the head of the valve are analyzed by ANSYS. On the other hand, the numerical results are verified by the experiment. The results show that the temperature of the head of the solenoid valve increases with the current increasing firstly. Second, the highest temperature of the head is obtained so the current can be selected. Third, the coefficient of thermal conductivity of the head of the valve is obtained, which can be applied to other analysis of the solenoid valve.
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Ai, Xiaolan, Matthew Wilmer, and David Lawrentz. "Development of Friction Drive Transmission." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63073.
Повний текст джерелаАнотація:
Friction drive is a mechanical device that utilizes friction force to transmit torque and power. Since the power is transferred through shearing a thin layer of highly pressurized lubricant film formed between the mating surfaces. Friction drive possesses desired performance attributes that pertain to its unique operating principles. These attributes include high mechanical efficiency, minimal backlash, low noise and vibration and high-speed capability. The power density of a friction drive can be very high when operated at elevated speeds. These performance features, in conjunction with its inherent manufacturing simplicity, make friction drives suitable candidates for a host of applications. The current global technology trend towards electrification and increasing use of electric machines in auxiliary drives for both automotive and industrial applications presents a good opportunity for friction drives as a cost-effective alternative to conventional gear drives. The smooth high-speed performance feature of friction drives allows the use of more efficient high-speed motors to reduce motor size and thus improve system power density. A novel cylindrical friction drive was developed [1,2] for electric oil pump applications. The friction drive is to be integrated with an electric motor to provide necessary speed reduction. The friction drive, as shown in Figure 1, is comprised of an outer ring, a sun roller, a loading planet, two supporting planets and a stationary carrier. The sun roller is set eccentric to the outer ring to generate a wedge gap that facilitates a torque actuated loading mechanism for the friction drive. The loading planet is properly assembled in the wedge gap with frictional contact with the sun roller and the outer ring and is elastically supported on the carrier. By altering the ratio of the support stiffness to contact stiffness, the actual operating friction coefficient of the friction drive can be changed to suit for desired performance regardless the wedge angle. This provides a grater freedom for design optimization. Design analysis was presented and a FE model was developed to quantify design parameters. Prototypes of the friction drive were fabricated for testing. Major geometry parameters are listed in Table 1. Extensive testing was conducted to evaluate its performance. Figure 2 shows the schematic of test apparatus. It is comprised of a drive motor, a high-speed spindle, and a hydraulic brake pump. The motor drives the spindle through a rubber belt and a pair of pulleys. The spindle shaft connects to the input shaft of the friction drive thought an input torque meter. The output shaft of the friction drive couples to the hydraulic pump through an output torque meter. The torque meters pick up both speed and torque signals at input and output shafts of the friction drive, respectively. Thermo-couples are mounted to monitor temperatures at planet support shafts and at bearings of input and output shafts. An accelerometer was placed on the back plate of a mounting bracket to which the friction drive was bolted. It monitors the vibration signals of the friction drive for reference and safety purposes. A data acquisition system was used to collect and process all signals at predetermined sampling rate. The friction drive offered a consistent smooth and quite performance over a wide range of operating conditions. It was capable of operating at an elevated speed of up to 12000 rpm with adequate thermal characteristics. Figure 3 shows the steady sate temperature contour map as function of input shaft speed and output shaft torque. Results demonstrated that the friction drive has high power transmission efficiency under various test conditions. The peak efficiency exceeded 97%. Figure 4 plots the overall system efficiency as a function of output torque for various input speeds. Results also confirmed that the stiffness of the elastic support has an important impact on performance. The elastic support stiffness, in conjunction with, the contact stiffness determines the actual operating friction coefficient at the frictional contacts.
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Kruhol, Mykola, Oleksandr Lasurenko, and Victor Vanin. "An Algebraic Model of Gas-Hydraulic Network of Mechanisms with Electric Drive in the Problem of Thermal Power Plant Auxiliaries Optimization." In 2020 IEEE KhPI Week on Advanced Technology (KhPIWeek). IEEE, 2020. http://dx.doi.org/10.1109/khpiweek51551.2020.9250085.
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Wang, Guangyao, Dong Sam Ha, and Kevin G. Wang. "Low-Temperature Thermal Energy Harvesting Using Solid/Liquid Phase Change Materials." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87956.
Повний текст джерелаАнотація:
This paper presents the design, fabrication, and analysis of a prototype system that demonstrates the use of a solid/liquid phase change material (PCM), namely pentadecane (C15H32), to harvest thermal energy associated with relatively low temperature and small temperature variation (e.g., 1°C to 20°C). The fundamental idea is to utilize the volume expansion of the PCM in the melting process to pressurize a hydraulic fluid, which is then released to drive a direct current (DC) water turbine generator. The prototype features the use of a tube system to store degassed and encapsulated PCM packages, therefore can be easily scaled to meet different energy output requirements. The performance of the prototype is assessed through measurements of the peak pressure of the hydraulic fluid and the produced power profile. The dependence of the electrical energy output on external load resistance is investigated within the range of 25 Ohm to 250 Ohm. Further, a thermomechanical model is developed to characterize the energy conversion process. Specifically, the thermodynamic behavior of PCM and hydraulic fluid is modeled with the Tait equation of state. The structural mechanics is modeled using the linear elasticity theory. The peak pressure predicted by the model agrees reasonably well with the experimental measurement, with a discrepancy of 3.40%. Finally, a series of numerical parameter studies are conducted to investigate the effects of the structural stiffness and the volume fraction of the PCM, indicating possible methods to improve the thermal efficiency and the specific energy output of the prototype system.
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Singh, Kris, Indresh Rampall, and Joseph Rajkumar. "On the Thermal-Hydraulic Essentials of the Holtec Inherently Safe Modular Underground Reactor (HI-SMUR) System." In ASME 2011 Small Modular Reactors Symposium. ASMEDC, 2011. http://dx.doi.org/10.1115/smr2011-6633.
Повний текст джерелаАнотація:
HI-SMUR 140 is a small (145 MWe) modular pressurized water reactor designed to harness fission energy without the use of a recirculation pump. HI-SMUR’s core resides deep underground in a thick-walled reactor vessel (RV) enclosed by a stainless steel-lined reinforced concrete “Reactor Well”. The HI-SMUR Nuclear Steam Supply System (NSSS) is a conjugated pressure vessel assemblage wherein the steam generator(s) are integrally joined to the RV, i.e., without any interconnecting piping, and the pressurizer is integral to the reactor vessel. There are no penetrations in the RV for over a height of 120 feet above the reactor core, which precludes the scenario of loss of coolant to the core from a postulated pipe break event. The rejection of decay heat from the reactor in the wake of a scram is engineered to occur without the aid of on-site or off-site power, making the HI-SMUR NSSS demonstrably capable of withstanding a cataclysmic environmental phenomenon of Fukushima’s intensity without loss of core cooling or without precipitating any damage to the plant or the surrounding environment. The system design places a premium on accessibility and maintainability of vital equipment such as the steam generators, RV internals, and the control rod drive assemblies. This paper is the first in a series of papers planned to explain and quantify the performance and safety aspects of HI-SMUR 140. In this paper, the thermal-hydraulic characteristics of the HI-SMUR NSSS are explored using classical hydraulic correlations which have served as the tool for the scoping parametric study of the system. In particular, the stability of the system under varying power output conditions and the long-term reliability of the fuel under the most adverse thermal/hydraulic conditions are presented.
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Mehta, Anjna R., Hardayal S. Mehta, Hwang Choe, George B. Inch, and Roy Corieri. "Thermal-Hydraulic and LBB Evaluations to Justify Short-Term Plant Operation With a CRD Return Line Susceptible to Potential Thermal Stratification." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2560.
Повний текст джерелаАнотація:
Most of the BWR reactor pressure vessels have control rod drive hydraulic return (CRDHR) line nozzles. Each vessel has one such nozzle, typically 3–4 inches in diameter, and generally located 68–100 inches above the top of the active fuel. The CRDHR line was designed to provide a reactor pressure reference to the CRD system and to return to the reactor vessel exhaust water from CRD movement and water in excess of system requirements. The horizontal section of the piping near the CRDHR line nozzle is susceptible to thermal striping. Many of the BWR plants have capped this line. Recently at an overseas plant that had not capped this line, an axial through-wall fatigue crack of approximately 1-inch length was observed at the safe end connected to this nozzle. Based on this overseas operating experience (OE), a domestic plant that also did not cap the line developed a comprehensive analysis, inspection and repair plan to address the OE. Thermal-hydraulic and leak-before-break (LBB) evaluations were conducted to justify continued plant operation at this plant until the upcoming planned mid-cycle maintenance outage when the inspection of the line could be conducted and if necessary any repairs/modifications could be implemented. A thermal-hydraulic model was developed considering the geometry, the density difference between the hot and cold streams, the frictional and local losses, and the external flow effects, to predict thermal stratification. The model was validated against the test data from a foreign and a domestic BWR plant. This model was conservatively applied without taking any credit for the external flow and predicted that at the typical flow rates at the plant, thermal stratification in an approximately 45-inch long horizontal segment of the piping cannot be ruled out. However, later plant testing showed that thermal stratification does not appear at 20 to 26 gpm of cold injection flow, and the model predicts the plant testing when a moderate external flow effect is considered. The model determined a flow rate that would eliminate the phenomenon. However, the hardware limitations precluded the increase in the flow rate. The question that needed to be addressed was whether any fatigue cracking initiated from the previous operation could lead to failure of the affected piping segment during operation until the next refueling outage. The piping material is Type 304 stainless steel with a nominal diameter of 3-inches. Several LBB evaluations were conducted assuming different levels of part through-wall and through-wall cracking. Limit load equations of Appendix C of ASME Section XI were used to calculate the limiting critical crack lengths and depths. The leak rates were calculated using a modified two-phase flow model. The LBB evaluations concluded that short-term plant operation to next refueling outage is justified. The inspection findings, the temperature monitoring hardware installation, and the monitoring results obtained during the mid-cycle outage are also discussed.
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Yang, Zhuo, Tariq Amin Khan, Wei Li, Hua Zhu, Zhijian Sun, Zhengjiang Zhang, Jincai Du, and Jianxin Zhou. "Thermal-Hydraulic Performance and Optimization of Tube Ellipticity in a Plate Fin-and-Tube Heat Exchanger." In ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipack2018-8448.
Повний текст джерелаАнотація:
The flow field inside the heat exchangers is associated with maximum heat transfer and minimum pressure drop. Designing a compact heat exchanger and employing various techniques to enhance its overall performance has been widely investigated and still an active research field. However, few researches deal with thermal optimization. The application of elliptic tube is an effective alternative to circular tube which can reduce the pressure drop significantly. In this study, numerical simulation and optimization of variable tube ellipticity is studied at low Reynolds numbers. The three-dimensional numerical analysis and a multi-objective genetic algorithm (MOGA) with surrogate modelling is performed. Two row tubes in staggered arrangement in fin-and-tube heat exchanger is investigated for combination of various elliptic ratio (e = minor axis/major axis) and Reynolds number. Tube elliptic ratio ranges from 0.2 to 1 and Reynolds number ranges from 150 to 750. The tube perimeters are kept constant while changing the elliptic ratio. The numerical model is derived based on continuum flow approach and steady-state conservation equations of mass, momentum and energy. The flow is assumed as incompressible and laminar due to low inlet velocity. Results are presented in the form of Colburn factor, friction factor, temperature contours and streamline contours. Results show that increasing elliptic ratio increases the friction factor due increased flow blocking area, however, the effect on the Colburn factor is not significant. Moreover, tube with lower elliptic ratio followed by higher elliptic ratio tube has better thermal-hydraulic performance. To achieve maximum heat transfer enhancement and minimum pressure drop, the Pareto optimal strategy is adopted for which the CFD results, Artificial neural network (ANN) and MOGA are combined. The tubes elliptic ratio (0.2 ⩽ e ⩽ 1.0) and Reynolds number (150 ⩽ Re ⩽ 750) are the design variables. The objective functions include Colburn factor (j) and friction factor (f). The CFD results are input into ANN model. Once the ANN is computed and its accuracy is checked, it is then used to estimate the model responses as a function of inputs. The final trained ANN is then used to drive the MOGA to obtain the Pareto optimal solution. The optimal values of these parameters are finally presented.