scholarly journals Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 751-760
Author(s):  
Lei Lei
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Transfer Performance ◽  
Analysis Model ◽  
Accurate Analysis ◽  
Testing Algorithm

AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.

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.

An investigation into gravity independent oscillating heat pipes

2012 ◽  
Author(s):  
◽  
Aaron A. Hathaway
Keyword(s):  
Heat Transfer ◽  
Contact Angle ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Heat Pipes ◽  
Experimental Results ◽  
Transfer Performance ◽  
Channel Diameter ◽  
Inverted Position ◽  
Oscillating Motion

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] A number of oscillating heat pipes (OHPs) with unbalanced structures were investigated in an effort to develop methods enabling OHPs to be gravity independent. The unbalanced structures investigated herein include the effects of uneven turn and check valves. Two 2-D and two 3-D tubular uneven-turn OHPs, four miniature uneven-turn OHPs, and one OHP with check-valves were investigated. At the same time, the theoretical analysis of the maximum channel diameter was conducted in order to find the primary factor affecting the channel size in an OHP. A model was developed that attempts to determine the maximum channel diameter by considering the contact angle effect. It is found that the contact angle significantly affects the maximum channel diameter of an OHP. In order to verify that the uneven-turn structure can generate the oscillating motion in an OHP, a heat pipe with 3 turns in the condenser and 6 turns in the evaporator was first tested. The heat pipe with uneven turns can generate and maintain oscillating motion. When the turn number increases with 16 turns in the condenser and 20 turns in the evaporator, the heat transfer performance can be further increased. An experimental investigation of a new 3-D OHP with uneven turn design was conducted in order to further develop a gravity independent OHP. Experimental results show that the uneven turn OHP developed herein can start the oscillating motion in the negative vertical position (the evaporator being above the condenser) and demonstrate that the uneven turn OHPs can significantly reduce the effect of gravity on the heat transport capability in an OHP. Three miniature OHPs (18-turn acetone OHP, 18-turn water OHP, and 20-turn acetone OHP) were developed and tested to determine whether the uneven-turn OHPs can function in a high-g environment. Experimental results demonstrate that these miniaturized uneven turn designs are extremely capable in high gravity environments and will operate effectively in any orientation. An OHP with check valves has been successfully developed and tested to determine the check valve effect on the oscillating motion and heat transfer performance in an OHP. Experimental results show that the OHP with check valves can function well in both the inverted and vertical positions with little variation between the two positions in performance once startup occurred, while the control OHP without check valves which had the same channel layout was not able to achieve startup in the inverted position. This shows that the check valves allowed the OHP to operate in the inverted position first achieving startup and then maintain oscillating motion.

Experimental Study on Heat Pipe Radiator in Cooling Electronic Apparatus

2012 ◽  
Vol 197 ◽  
pp. 216-220
Author(s):  
Zhong Chao Zhao ◽  
Rui Ye ◽  
Gen Ming Zhou
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Heat Transfer Performance ◽  
Electronic Device ◽  
Transfer Performance ◽  
Air Velocity ◽  
Electronic Apparatus ◽  
Operational Temperature

To solve the cooling problem in modern electronic device, a kind of heat pipe radiator was designed and manufactured in this paper. The heat transfer performance of heat pipe radiator and its relationship with air velocity were investigated by experimental method. The experimental results show that the heat pipe radiator can meet the temperature requirement of electronic device with the power range from 40W to 160W. To keep the operational temperature of electronic device with power of 160W under 75°C，the air velocity should be keep at 1.7m/s. The heat dissipation performance of heat pipe radiator was enhanced with the air velocity increased from 0.2m/s to 1.7m/s.for the electronic equipment with power of 160W.

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%.

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