Enhancement of loop heat pipe heat transfer performance with superhydrophilic porous wick

2020 ◽  
Vol 156 ◽  
pp. 106466
Author(s):  
Hao Guo ◽  
Xianbing Ji ◽  
Jinliang Xu
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Loop Heat Pipe ◽  
Transfer Performance ◽  
Porous Wick ◽  
Pipe Heat

Effect of Sintering Temperature Curve in Wick Manufactured for Loop Heat Pipe with Flat Evaporator

2014 ◽  
Vol 595 ◽  
pp. 24-29 ◽  
Author(s):  
Shen Chun Wu ◽  
Kuei Chi Lo ◽  
Jia Ruei Chen ◽  
Chen Yu Chung ◽  
Weie Jhih Lin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Sintering Temperature ◽  
Temperature Curve ◽  
Loop Heat Pipe ◽  
Transfer Performance ◽  
Total Thermal Resistance ◽  
Flat Evaporator ◽  
Increasing Temperature

This paper specifically addresses the effect of the sintering temperature curve in manufacturing nickel powder capillary structure (wick) for a loop heat pipe (LHP) with flat evaporator. The sintering temperature curve is composed of three regions: a region of increasing temperature, a region of constant temperature, and a region of decreasing temperature. The most important region is the increasing temperature region, as the rate of temperature increase directly affects the performance of the wick.When the slope of the region of increasing temperature is 0.8 (equivalent to 8 OC/min), the structure of the manufactured wick is complete, with the best heat transfer performance result. Experimental resultsshowed that the optimal heat transfer performance is 160W, the minimal total thermal resistance is approximately 0.43OC/W, and the heat flux is 17W/cm2; the optimal wick manufactured has an effective pore radius of 5.2 μm, a permeability of 5.9×10-13m2, and a porosity of 64%.

Investigation on Heat Transfer Performance of Heat Pipe Grinding Wheel in Dry Grinding

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Qingshan He ◽  
Yucan Fu ◽  
Jiajia Chen ◽  
Wei Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Grinding Wheel ◽  
Grinding Temperature ◽  
Transfer Performance ◽  
Equivalent Thermal Conductivity ◽  
Dry Grinding ◽  
Pipe Heat

The use of fluid in grinding enhances heat exchange at the contact zone and reduces grinding temperature. However, the massive use of fluid can cause negative influences on environment and machining cost. In this paper, a novel method of reducing grinding temperature based on heat pipe technology is proposed. One new heat pipe grinding wheel and its heat transfer principle are briefly introduced. A heat transfer mathematical model is established to calculate equivalent thermal conductivity of heat pipe grinding wheel. Compared with the wheel without heat pipe, heat transfer effect of heat pipe grinding wheel is presented, and the influences of heat flux input, cooling condition, wheel speed, and liquid film thickness on heat transfer performance are investigated. Furthermore, dry grinding experiments with two different wheels are conducted to verify the cooling effectiveness on grinding temperature. The results show that thermal conductivity of the wheel with heat pipe can be greatly improved compared to the one without heat pipe; heat transfer performance of heat pipe grinding wheel can change with different grinding conditions; meanwhile, grinding temperatures can be significantly decreased by 50% in dry grinding compared with the wheel without heat pipe.

Effect of Increasing Wick Evaporation Area on Heat Transfer Performance for Loop Heat Pipes

2013 ◽  
Vol 711 ◽  
pp. 223-228 ◽  
Author(s):  
Shen Chun Wu ◽  
Jhih Huang Gao ◽  
Zih Yan Huang ◽  
Dawn Wang ◽  
Cho Jeng Huang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Surface Area ◽  
Heat Transfer Performance ◽  
Heat Pipes ◽  
Loop Heat Pipe ◽  
Transfer Performance ◽  
Loop Heat Pipes ◽  
Heat Transfer Capacity

This study investigates the effects of increasing the evaporating area of wick in a loop heat pipe (LHP). This work attempts to improve the performance of the loop heat pipe by increasing the number of grooves and thereby the surface area of the wick. The number of grooves is increased from eight to twelve. Experimental results show that increasing the number of grooves not only increases the surface area of the wick but also enhances LHP performance. When the evaporating surface area increases by 50%, which corresponds to increasing the number of grooves from eight to twelve, the heat transfer capacity increases from 310W to 470W and the thermal resistance is reduced from 0.21°C/W to 0.17°C/W. According to preliminary measurements, increasing the number of grooves in the loop heat pipe is highly promising for improving the heat transfer performance.

scholarly journals Experimental study on heat transfer performance of gas-liquid pulsating heat pipe heat exchanger

2020 ◽  
Vol 165 ◽  
pp. 06048
Author(s):  
Fumin Shang ◽  
Chaoyue Liu ◽  
Qingjing Yang ◽  
Yifang Dong ◽  
Weijia Cao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Heat Transfer Performance ◽  
Waste Heat ◽  
Transfer Performance ◽  
Pulsating Heat Pipe ◽  
Heat Exchange Equipment ◽  
Pipe Heat

With the continuous development of industrial technology, the safety and efficiency of thermal equipment work in related industries and industrial fields are facing many problems. First, with the improvement of integrated level, the size of electronic components is getting smaller and smaller, and the heat load per unit area is increasing, which makes the traditional heat dissipation method difficult to meet the requirements; second, with the increase of energy-saving pressure, the temperature difference of low-temperature waste heat recovery is reduced, and the traditional heat exchange equipment is difficult to meet the working requirements. The pulsating heat pipe has the characteristics of small volume and excellent heat transfer performance. In view of the heat transfer performance of the pulsating heat pipe, we designed the gas-liquid pulsating heat pipe heat exchanger and studied its heat transfer performance, which has been verified to be effective.

Heat transfer performance of a compact loop heat pipe with alumina and silver nanofluid

2018 ◽  
Vol 136 (1) ◽  
pp. 211-222 ◽  
Author(s):  
Emerald Ninolin Stephen ◽  
Lazarus Godson Asirvatham ◽  
Ramachandran Kandasamy ◽  
Brusly Solomon ◽  
Gnana Sundari Kondru
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Loop Heat Pipe ◽  
Transfer Performance

Study of Nickel Wick Structure Applied to Loop Heat Pipe with Flat Evaporator

2016 ◽  
Vol 723 ◽  
pp. 282-287 ◽  
Author(s):  
Shen Chun Wu ◽  
Shih Hsuan Yen ◽  
Wei Chen Lo ◽  
Chen Yu Chung ◽  
Shen Jwu Su
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Transfer Performance ◽  
Total Thermal Resistance ◽  
Wick Structure ◽  
Flat Evaporator

This study investigated the use of sintered Nickel powder as the wick material of Loop heat pipe with flat evaporator (Flat loop heat pipe, FLHP) and its effect on the heat transfer performance. Add the 1-heptanol into water and form Self-rewetting Fluid (SRF), resulting in the Marangoni effect. The colder liquid can be transport to the heating surface, delaying the occurrence of dry-out and increasing the critical heat load. This paper use Surface tension measurements to measure the change of 1-heptanol SRF, then it was apply to nickel wick FLHP as working fluid to investigate its effect on the heat transfer performance. This study successfully established production process of Nickel wick structure. Results of wick structure for the effective pore radius of 2.6 μm, porosity of 62%, permeability of 5.7 × 10-13m2. Results of Surface tension measurements show that 1-heptanol aqueous solution’s surface tension increases with increasing temperature, Results from applying 0.1% 1-heptanol aqueous solution to FLHP as working fluid. For performance testing show that the critical heat load was 240 W and the total thermal resistance was 0.77 ° C/W. Compared with FLHP with pure water, SRF raised the maximum heat flux of 70%, the total thermal resistance of the system reduces 40%, SRF has the potential to enhance the heat transfer performance of FLHP.

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