Heat-transfer rate in the condenser section of a heat pipe

1973 ◽  
Vol 25 (3) ◽  
pp. 1115-1117
Author(s):  
V. Ya. Sasin ◽  
A. Ya. Shelginskii
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Condenser Section

Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector

2012 ◽  
Author(s):  
Shota Sato ◽  
Shigeki Hirasawa ◽  
Tsuyoshi Kawanami ◽  
Katsuaki Shirai
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Solar Collector ◽  
Transfer Rate ◽  
Thermal Conductance ◽  
Filling Ratio ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Single Tube

We experimentally study the thermal conductance of single-tube and loop heat pipes for a solar collector. The evaporator of the heat pipe is 1 m long, 6 mm in diameter and has 30° inclination. The thermal conductance is defined as the heat transfer rate divided by the temperature difference between the evaporator-wall and the condenser-wall. Effects of heat transfer rate, saturation temperature of the working fluid, liquid filling ratio, inclination angle, and position of the evaporator on the thermal conductance are examined. We found that the thermal conductance of the 30°-inclined loop heat pipe with an upper-evaporator is 40–50 (W/K), which is 1.8 times higher than that of the vertical loop type and 3 times higher than that of the single-tube type. Thus, the inclined loop heat pipe is preferable for a solar collector. There is an optimum liquid filling ratio. When the liquid filling ratio is too small, a dry-out portion appears in the evaporator. When the liquid filling ratio is too large, the liquid flows in the condenser to decrease heat transfer area. Also we numerically analyze the thermal conductance of a vertical loop heat pipe.

scholarly journals Three-dimensional transient mathematical model to predict the heat transfer rate of a heat pipe

2015 ◽  
Vol 7 (2) ◽  
pp. 168781401456781 ◽  
Author(s):  
S Boothaisong ◽  
S Rittidech ◽  
T Chompookham ◽  
M Thongmoon ◽  
Y Ding ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Three Dimensional

The Effect of Fill Volume on Heat Transfer From Air-Cooled Thermosyphons

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Christina A. Pappas ◽  
Paul M. De Cecchis ◽  
Donald A. Jordan ◽  
Pamela M. Norris
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Air Flow ◽  
Condenser Section ◽  
Evaporator Temperature ◽  
Evaporator Section ◽  
Fill Volume ◽  
Inner Diameter ◽  
Cooling Air Flow

The effect of fill volume on the heat transfer performance of a cylindrical thermosyphon with an aspect ratio (ratio of the length of the evaporator section to the inner diameter) of 2.33 immersed in a cooling air flow is investigated. The fill volume was systematically varied from 0% to 70.3% of the volume of the evaporator section in a copper-water thermosyphon having an inner diameter of 19 mm. The condenser section was immersed in a uniform air flow in the test section of an open return wind tunnel. The heat transfer rate was measured as a function of evaporator temperature and fill volume, and these results were characterized by three distinct regions. From 0% to roughly 16% fill volume (Region I), the low rate of heat transfer, which is insensitive to fill volume, suggests that dry out may be occurring. In Region II (extending to approximately 58% fill volume), the heat transfer rate increases approximately linearly with fill volume, and increasing evaporator temperature results in decreased rate of heat transfer. Finally, in Region III (from roughly 58–70.3%), the rate of heat transfer increases more rapidly, though still linearly, with fill volume, and increasing evaporator temperature results in increased rate of heat transfer. The thermosyphon rate of heat transfer is greatest at 70.3% fill volume for every evaporator temperature.

scholarly journals HEAT TRANSFER RATE OF SINTERED ZEOLITE WICK HEAT PIPE

2020 ◽  
Vol 5 (1) ◽  
pp. 5
Author(s):  
Luh Putu Ike Midiani ◽  
I Nyoman Suprapta Winaya ◽  
Wayan Nata Septiadi ◽  
Made Sucipta
Keyword(s):  
Heat Transfer ◽  
Grain Size ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Natural Zeolite ◽  
Transfer Rate ◽  
Powder Form ◽  
Sintering Process ◽  
Process Calculation

This paper discusses about heat transfer rate in heat pipe with sintered zeolite wick. The type of zeolite is natural zeolite and activated zeolite. Zeolite used in powder form  divided into two grain size i.e. 100 µm and 200 µm. Wick were made by sintering process. Calculation of the heat transfer rate for sintered zeolite heat pipe shows sintered zeolite activates heat pipe has the highest heat transfer rate.

Experimental Study on Flow Visualizing and Heat Transfer Characteristic of Pulsating Heat Pipe

2007 ◽  
Author(s):  
Li Jia ◽  
Dayan Yin
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Flow Patterns ◽  
Bulk Flow ◽  
Experimental Results ◽  
Pulsating Heat Pipe ◽  
Transition Flow ◽  
Fill Ratio

The flow of looped pulsating heat pipe was studied by a visualizing experiment, and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The experimental results indicate that bulk flow, transition flow and annular flow are the major flow patterns in PHP. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred form bulk flow to semi-annual flow and annual flow, and the performance of heat transfer is improved. In the experiment, nuclear boiling, the convergence and break up of liquid-plug and vapor-slug were observed. The influence characterization has been done for the variation of fill ration, heat transfer rate, non-condensable gas and inclination angle. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%; the heat resistance is decreased with heat transfer rate, and non-condensable gas also has significant influence on it. The temperature of tubes in heating, condensing and observe sections were recorded, The fluctuation of heat pipe wall temperature was analysed, and the phenomena of suddently increase or decrease of temperature, the unregular fluctuation of temperature were analyzed. Otherwise the response time under different conditions was also analyzed.

The Sonic Limit in Sodium Heat Pipes

1973 ◽  
Vol 95 (2) ◽  
pp. 218-223 ◽  
Author(s):  
E. K. Levy ◽  
S. F. Chou
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Heat Pipes ◽  
Vapor Condensation ◽  
Condensation Process ◽  
Recombination Reaction ◽  
Condenser Section ◽  
Sonic Point ◽  
Limit Heat Transfer

The results of an analytical study of the vapor dissociation–recombination and homogeneous vapor condensation phenomena in sodium heat pipes are described. It is shown that neither the dissociation–recombination reaction nor the vapor condensation process has a large influence on the sonic-limit heat transfer rate. The single most important factor is shown to be the wall shear stress in the heat-pipe vapor passage. The friction effects control the location of the sonic point, determine if the flow in the condenser section will be subsonic or supersonic, and decrease the sonic-limit heat transfer rate to values which can be substantially lower than those which are predicted from inviscid analyses.

Experimental Research on Heat Transfer Characteristics of Pulsating Heat Pipe

2008 ◽  
Author(s):  
Li Jia ◽  
Yan Li
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Experimental Research ◽  
Transfer Rate ◽  
Experimental Results ◽  
Pulsating Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Fill Ratio ◽  
Transfer Characteristics

Experimental research was conducted to understand heat transfer characteristics of pulsating heat pipe in this paper. The PHP is made of high quality glass capillary tube. The heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage under different fill ratio. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appeares in top heating condition. The flow pattern in PHP is transferred form bulk flow to semi-annual flow and annual flow, and the performance of heat transfer is improved for down heating case under different fill ratios and heat transfer rate. The experimental results show that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

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