Loop Heat Pipe Operating Temperature Dependence on Liquid Line Return Temperature

2004 ◽  
Author(s):  
Paul Rogers ◽  
Jeffrey Perez ◽  
Jentung Ku ◽  
Mark Kobel ◽  
Jay Ochterbeck ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Heat Pipe ◽  
Operating Temperature ◽  
Loop Heat Pipe ◽  
Liquid Line

Hydraulic operating temperature control of a loop heat pipe

2015 ◽  
Vol 86 ◽  
pp. 796-808 ◽  
Author(s):  
Wukchul Joung ◽  
Kee Sool Gam ◽  
Yong-Gyoo Kim ◽  
Inseok Yang
Keyword(s):  
Heat Pipe ◽  
Temperature Control ◽  
Operating Temperature ◽  
Loop Heat Pipe

scholarly journals One-dimensional steady-state mathematical model of a novel loop heat pipe with liquid line capillary wick

2019 ◽  
Vol 38 (1) ◽  
pp. 253-273 ◽  
Author(s):  
Meng Fanxi ◽  
Quan Zhang ◽  
Sheng Du ◽  
Chang Yue ◽  
Xiaowei Ma
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Heat Pipe ◽  
Characteristic Point ◽  
Loop Heat Pipe ◽  
One Dimensional ◽  
Liquid Line ◽  
Working Medium ◽  
Compensation Chamber ◽  
Relative Errors

A novel loop heat pipe used for data center with a liquid line wick is designed, and its one-dimensional steady-state mathematical model is developed based on the energy and thermodynamic equilibrium of each component and the simulation results were validated by comparing with the experimental data in this work. The compensation chamber of the loop heat pipe was removed, and a section of capillary wick was added in the end of liquid line in order to reduce heat leakage and vapor backflow and increase working medium circulation power. The mathematical model of the novel loop heat pipe can be used to predict the operating temperature of each characteristic point with small relative errors of <13%. A parametric study of the steady-state performance characteristics including the effects of material, diameter, length, and porosity of liquid line wick are conducted, which provides a powerful basis for the design of novel loop heat pipe experiment.

Experimental Study on Heat Transfer Capability of a Miniature Loop Heat Pipe

2016 ◽  
Author(s):  
Guohui Zhou ◽  
Ji Li ◽  
Lucang Lv
Keyword(s):  
Heat Pipe ◽  
Heat Load ◽  
Electronics Cooling ◽  
High Heat ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Evaporator Temperature ◽  
Liquid Line ◽  
Horizontal Orientation ◽  
Flat Evaporator

In this paper, a miniature loop heat pipe (mLHP) with a flat evaporator is illustrated and investigated experimentally, with water as the working fluid. The mLHP can be applied for the mobile electronics cooling, such as tablet computers and laptop computers, with a 1.2 mm thick ultra-thin flat evaporator and a thickness of 1.0 mm for the vapor line, liquid line and condenser. A narrow sintered copper mesh in the liquid line and a part of the condenser as the secondary wick can promote the flow of the condensed working fluid back to the evaporator. The experimental results showed that the mLHP could start up successfully and operate stably at low heat load of 3 W in the horizontal orientation, and transport a high heat load of 12 W (the heat flux of 4 W/cm2) with the evaporator temperature below 100 °C in different test orientations by natural convection, showing good operational performance against gravity field. The minimum mLHP thermal resistance of 0.32 K/W was achieved at the input heat load of 12 W in the horizontal orientation.

Steady State Modeling of LHP and Analysis

2010 ◽  
Author(s):  
Yan Chen ◽  
Lin Cheng ◽  
Gongming Xin ◽  
Tao Luan
Keyword(s):  
Steady State ◽  
Ambient Temperature ◽  
Heat Pipe ◽  
Heat Sink ◽  
Heat Load ◽  
Operating Temperature ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Heat Sink Temperature ◽  
Transition Heat

The loop heat pipe (LHP) was invented in Russia in the early 1980’s. It is a two-phase heat transfer device that utilizes the evaporation and condensation of a working fluid to transfer heat, and the capillary force developed in fine porous wicks to circulate the fluid. The temperature of LHP evaporator as functions of the heat load, sink temperature, ambient temperature is an important parameter which can reflect the performance of an LHP. Many factors can affect the LHP operating temperature and which can be divided into two parts: external and internal. The external factors including heat sink temperature, ambient temperature, fluid forces, the position between heat source and heat sink and the heat exchange between LHP and ambient. The internal factors related to the design and structure of the LHP, for example, the charging amount of the working fluid and the distribution status of the liquid phase during the LHP operating. Based on Sinda/Fluint software an ammonia-stainless steel steady state model of loop heat pipe was established, the impacts on the LHP operating temperature induced by alterable heat loads under 3 operating cases (the different position between evaporator and condenser, the changing of ambient temperature and the changing of heat sink temperature) were analyzed and conclusions were made. Changing the position between evaporator and condenser has a significant influence on the LHP operating temperature. Anti-gravity operation will reduce the performance of the LHP, this phenomenon is obviously in low heat load range. Further more, increasing of fluid pressure drop in the loop will induce decreasing of the LHP performance. The temperature difference between ambient and heat sink will influence the transition heat load (from variable conductance mode to fixed conductance mode), the bigger the temperature difference the higher the transition heat load.

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