Modeling Heat Loss through Pistons and Effect of Thermal Boundary Coatings in Diesel Engine Simulations using a Conjugate Heat Transfer Model

2016 ◽  
Author(s):  
Prithwish Kundu ◽  
Riccardo Scarcelli ◽  
Sibendu Som ◽  
Andrew Ickes ◽  
Yan Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Heat Loss ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model

Flow and Heat Transfer Study in an Autoclave for Hydrothermal Crystal Growth With a Three-Dimensional Conjugate Heat Transfer Model

2002 ◽  
Author(s):  
Hongmin Li ◽  
Edward A. Evans ◽  
G.-X. Wang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Crystal Growth ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Model ◽  
Thick Wall ◽  
Transfer Model ◽  
Hydrothermal Crystal Growth ◽  
Flow And Heat Transfer ◽  
Isothermal Wall

Numerical modeling becomes an important technique to study hydrothermal crystal growth since experimental measurements in hydrothermal autoclaves are extremely difficult due to the high pressure and high temperature growth conditions. In all existing models for hydrothermal growth, isothermal boundary conditions are assumed, although electric heaters are employed around the outside surface of the thick autoclave wall in practice. In this paper, a conjugate heat transfer model based on an industry size autoclave is developed to investigate the validity of such an assumption. The model includes not only turbulent fluid flow and heat transfer of the solution but also the heat conduction in the thick wall. The outside surfaces of the wall are under constant heat flux conditions, simulating electric resistance heating used in practice. Non-uniformity of the heat flux in the circumferential direction is also introduced in the model. The results indicate that the temperature at the solution/wall interface is far away from uniform. The isothermal wall boundary condition in previous efforts is questionable. Predictions of the isothermal wall model are analyzed. Parametric studies with the conjugate model show that total heat supply rate does not affect vertical uniformity dramatically. Heat loss can be lowered without affecting the flow and temperature fields if heaters are put half diameter or further away from the middle height (baffle) plane.

Numerical investigation of turbocharger turbine temperature field based on conjugate heat transfer

2021 ◽  
pp. 095440892110399
Author(s):  
Liang Peng ◽  
Zhenlei Chen ◽  
Yi Hu
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Transfer Model ◽  
Traditional Model ◽  
Test Results ◽  
Hypothetical Data ◽  
Volume Method

Aiming at the issues of low accuracy and poor feasibility of the analytical results of the turbocharger turbine temperature field under operating conditions, a full-domain conjugate heat transfer numerical model was established by the conjugate heat transfer and finite volume method. The temperature field characteristics of each component of the turbocharger turbine were analyzed. The numerical and experimental test results were compared and analyzed. The global conjugate heat transfer model avoids the input of a large number of hypothetical data on the interface between fluid and solid in the traditional model, and makes the calculation process closer to the actual situation. Through the comparison with the experimental results, the accuracy of the turbine temperature field obtained by the global conjugate heat transfer model is more reasonable and more accurate than that of the traditional model, which verifies the reliability and accuracy of the global conjugate heat transfer model.

Heat Efficiency of Trough Solar Vacuum Receiver

2014 ◽  
Vol 521 ◽  
pp. 23-27
Author(s):  
Jun Ming Liang ◽  
Jian Feng Lu ◽  
Jing Ding ◽  
Jian Ping Yang
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Heat Loss ◽  
Wall Temperature ◽  
Radiation Flux ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Parabolic Trough ◽  
Heat Efficiency ◽  
Solar Radiation Flux

The heat loss and thermal performance of solar parabolic trough vacuum receiver were experimentally measured and analyzed by heat transfer model. According to the present experiments, the heat loss of solar parabolic trough vacuum receiver has good agreement with the heat loss of vacuum receiver from Solel company. As the wall temperature increase from 108°C to 158°C, the heat loss of solar parabolic trough vacuum receiver remarkably increases from 35 Wm-2to 57 Wm-2. The heat transfer model of parabolic trough solar receiver is then theoretically investigated due to the energy balances between the heat transfer fluid, absorber tube, glass envelope and surroundings. When solar radiation flux is constant, the heat efficiency of solar parabolic trough system decreases with the wall temperature and oil temperature. When solar radiation flux or solar concentration ratio increases, the heat efficiency of solar parabolic trough system increases.

scholarly journals Effect Analysis on the Performance Enhancement and Emission Reduction of Diesel Engine Fueled with Biodiesel Fuel Based on an Improved Model

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Weigang Yu ◽  
Zhiqing Zhang ◽  
Bo Liu
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Performance Enhancement ◽  
Combustion Process ◽  
Weight Coefficient ◽  
Injection Rate ◽  
Heat Transfer Model ◽  
Biodiesel Fuel ◽  
Transfer Model ◽  
Load Characteristics

To increase the efficiency and accuracy of computing, an improved combined weight coefficient is used to develop an improved heat transfer model in AVL-BOOST environment. Similarly, a five-component biodiesel skeletal mechanism is employed to investigate the combustion process of biodiesel fuel. Then, the AVL-BOOST model is validated by the experimental results under different conditions. Finally, the improved heat transfer model is employed to investigate the propulsion and load characteristics of diesel engine fueled with biodiesel fuel in terms of power, BSFC, soot, and NOx emission. The result shows that the errors between experiment and simulation are less than 2% and the simulation model can predict the propulsion and load characteristics of the diesel engine. In addition, the comprehensive characteristic of case 5 is the best. Moreover, the big inject orifice is not beneficial to the fuel atomization and more soot is produced. Thus, it is very important to choose the appropriate injection rate reasonably.

Validation of Conjugate Heat Transfer Model for Rocket Cooling with Supercritical Methane

2016 ◽  
Vol 32 (3) ◽  
pp. 726-733 ◽  
Author(s):  
Marco Pizzarelli ◽  
Francesco Nasuti ◽  
Raffaele Votta ◽  
Francesco Battista
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model
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