Experimental Analysis on Internal Flow Field of Enhanced Heat Transfer Structure for Clean Gas Bus Engine Compartment

2020 ◽  
pp. 617-628
Author(s):  
Jiajie Ou ◽  
Lifu Li
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Experimental Analysis ◽  
Internal Flow ◽  
Engine Compartment ◽  
Enhanced Heat Transfer ◽  
Transfer Structure

Analysis of Heat Transfer Enhancement in Micro-scale Heat Sink Structure

2021 ◽  
pp. 1-11
Author(s):  
Long Wei ◽  
Zixuan Song ◽  
Tao Ren ◽  
Yun Liu
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Flow Field ◽  
Transfer Factor ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Straight Channel ◽  
Transfer Enhancement ◽  
Enhanced Heat Transfer ◽  
Heat Transfer Factor

Abstract With the increasing power requirements of electronic devices, high heat flux will cause serious damage to the devices. Based on the basic theory of micro-nano heat transfer, the series and topological microchannel heat sink models are established. The flow field characteristics and temperature distribution in the heat sink are analyzed by numerical calculation. The effects of channel structure on temperature, pressure drop, the Nusselt number and enhanced heat transfer factor are compared, and the micro-mechanism of heat transfer enhancement in microchannels is clarified. It is found that the Nusselt number of the flow field can be significantly increased by adding the triangular groove in the microchannel, and the enhanced heat transfer factor in the channel can be greatly improved by the topological structure. Further analysis of the factors such as angle a, diameter ratios γ and topological structures of the triangular groove shows that:When α = 70°,the Nusselt number of the flow field is 3.1 times of that of the straight channel, and the enhanced heat transfer factor is 2.7 times of that of it; compared with the straight channel, the comprehensive heat transfer performance of the microchannel with γ = 1/2 is improved by 31%; when using T.Tr.N. topology, the convective heat transfer of the microchannel is 2.6 times of that of the straight channel and the comprehensive heat transfer performance is increased by 5.9 times.

Enhanced Heat Transfer Structure Design for Ion Dump of EAST-NBI System Based on Hypervapotron

2017 ◽  
Author(s):  
Ling Tao ◽  
Chundong Hu ◽  
Yuanlai Xie
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Energy Deposition ◽  
High Energy ◽  
Operating Conditions ◽  
Quasi Steady State ◽  
Enhanced Heat Transfer ◽  
Steady State Operation ◽  
The Future ◽  
Transfer Structure

Ion dump is an important functional component of the Neutral Beam Injection (NBI) system of Experimental Advanced Superconducting Tokamak (EAST) for absorbing un-neutralized particles deflected by deflection magnets during neutralization, and by means of the corresponding measurement and analyzing method on it, the total energy deposition value and instantaneous energy deposition distribution of the deflected ion beam can be obtained. According to the operation mechanism of the NBI system, ion dump is directly subjected to high-energy particle bombardment for long time, the corresponding heat-loaded on its plates is high, so the temperature rise control is demanding. In order to realize the running power of 2–4MW and running pulse length of more than 100s or even 1000s in the future NBI system, the structure of the ion dump must be designed in accordance with the quasi-steady state operation requirements to provide the guarantee for the steady state operation of EAST system. The Hypervapotron structure based on the subcooled boiling principle is used as an alternative structure to enhance the heat transfer of this high-heat-flux component. According to the operating requirements, space requirements, measurement requirements and beam power distribution characteristics, the engineering design and implementation of ion dump based on the enhanced heat transfer structure is realized for the future long pulse quasi-steady NBI system. The computational results of the heat-fluid-solid coupling simulation based on the two-phase heat transfer are also confirmed the feasibility of the proposed ion dump structure under quasi-steady-state operating conditions. This study is of great significance to explore the optimal heat transfer structure for quasi-steady ion dump to realize the high current, quasi-steady state and high power operation of EAST-NBI system.

Experimental Study on the Influence of Film Cooling Hole Extraction on Heat Transfer and Flow Field in Internal Ribbed Cooling Channels of Turbine Blades

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Marlene Böttger ◽  
Martin Lange ◽  
Ronald Mailach ◽  
Konrad Vogeler
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Film Cooling ◽  
Turbine Blades ◽  
Internal Heat ◽  
Internal Flow ◽  
Cooling Channel ◽  
Thermochromic Liquid Crystal ◽  
Flow Measurements ◽  
Cooling Hole

Abstract Film cooling and internal passage cooling play a fundamental role in turbine blade cooling. As the cooling holes are fed by the internal crossflow, interaction of these both cooling strategies is implicated. The influence of film hole extraction on the internal flow field and heat transfer of a ribbed cooling channel is investigated in this study. Therefore, a rectangular cooling channel (AR = 2:1) is equipped with parallel ribs of four different geometries (90 deg ribs, 60 deg ribs, 60 deg V-shaped ribs, and 60 deg Λ-shaped ribs) and also with bleed holes at varying positions between the ribs. The different geometrical configurations are examined using 2D-particle image velocimetry (PIV) for flow measurements and transient thermochromic liquid crystal (TLC) technique for heat transfer measurements. Depending on the rib-induced heat transfer pattern, cooling hole positions in the rib segments are found, which can enhance passage internal heat transfer. 90 deg and 60 deg ribs show the best results for upstream hole positions regardless of the lateral positioning. V and Λ ribs reveal a benefit for lateral positioned cooling holes near the upstream rib.

scholarly journals Experimental Analysis for Internal Flow Field of Torque Converter

2019 ◽  
Vol 39 (5) ◽  
pp. 11-18
Author(s):  
Yasunori KUNISAKI ◽  
Shigeru MURATA ◽  
Yohsuke TANAKA ◽  
Tomoya TAKEDA
Keyword(s):  
Flow Field ◽  
Experimental Analysis ◽  
Internal Flow ◽  
Torque Converter

scholarly journals Application of the multi-field coupling enhanced heat transfer principle to the engine compartment design of clean gas bus

2020 ◽  
Vol 11 (1) ◽  
pp. 205-220
Author(s):  
Jiajie Ou ◽  
Lifu Li
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Flow Region ◽  
Transfer Principle ◽  
Engine Compartment ◽  
Enhanced Heat Transfer ◽  
Core Flow ◽  
Field Coupling ◽  
The Core ◽  
Block Area

Abstract. Clean gas engines, such as liquefied petroleum gas (LPG) engines, have high thermal loads on parts under equivalent specific combustion. This study examines the multi-field coupling enhanced heat transfer principle and its applications to the engine compartment of a typical LPG city bus. The field synergy enhanced heat transfer principle (FSP) was applied in the radiator assembly area. The FSP model yielded an optimum velocity -temperature gradient matching field that would improve convective heat transfer in this area. To strengthen the convective heat transfer ability of the limited cooling air in the cabin, temperature field homogenization (TFH) in the core flow region of the engine block area was achieved. The TFH optimization model helped minimize the temperature gradient in the core flow region and maximize it at the heat transfer boundary, and the optimum vector field and flow path were obtained. More comprehensive changes to the structural design were made according to the multi-field coupling enhanced heat transfer principles. The simulation results showed that in the comprehensive structure, the heat transfer efficiency of the radiator increased by 14.66 %, the average temperature of the air passages in the engine block area decreased by 22.23 %, and the heat dissipation coefficient of the engine body and engine cover increased by 4.60 times and 3.49 times, respectively.

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