Investigation of heat transfer characteristics of a two-phase closed thermosyphon

Shiraishi, Masao; Kikuchi, Kentaro; Yamanishi, T.

doi:10.1016/0198-7593(81)90039-4

Cited by 78 publications

(14 citation statements)

References 3 publications

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“…Imura et al [38] 14.72 75 Shiraishi et al [39] 22.37 75 Table 5. Results of the statistical analysis of the prediction of heat transfer coefficient in the evaporation section for different fluids with FR = 0.51.…”

Section: Ethanolmentioning

confidence: 99%

Experimental Investigation of the Thermal Performance of a Wickless Heat Pipe Operating with Different Fluids: Water, Ethanol, and SES36. Analysis of Influences of Instability Processes at Working Operation Parameters

Andrzejczyk

2018

Energies

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In this study, the influences of different parameters on performance of a wickless heat pipe have been presented. Experiments have been carried out for an input power range from 50 W to 300 W, constant cooling water mass flow rate of 0.01 kg/s, and constant temperature at the inlet to condenser of 10 °C. Three working fluids have been tested: water, ethanol, and SES36 (1,1,1,3,3-Pentafluorobutane) with different filling ratios (0.32, 0.51, 1.0). The wall temperature in different locations (evaporation section, adiabatic section, and condenser section), as well as operating pressure inside two phase closed thermosyphon have been monitored. The wickless heat pipe was made of 0.01 m diameter copper tube, which consists of an evaporator, adiabatic, and condensation sections with the same length (0.4 m). For all working fluids, a dynamic start-up effect caused by heat conduction towards the liquid pool was observed. Only the thermosyphon filled with SES36 was observed to have operation limitation caused by achieving the boiling limit in TPCTs (two-phase closed thermosyphons). The geyser boiling effect has been observed only for thermosyphon filled with ethanol and for a high filling ratio. The performance of the thermosyphon determined the form of the heat transfer resistance of the TPCT and it was found to be dependent of input power and filling ratio, as well as the type of working fluid and AR (aspect ratio). Comparison with other authors would seem to indicate that lower AR results in higher resistance; however, the ratio of condenser section length to inside diameter of pipe is also a very important parameter. Generally, performance of the presented thermosyphon is comparable to other constructions.

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Section: Ethanolmentioning

confidence: 99%

Experimental Investigation of the Thermal Performance of a Wickless Heat Pipe Operating with Different Fluids: Water, Ethanol, and SES36. Analysis of Influences of Instability Processes at Working Operation Parameters

Andrzejczyk

2018

Energies

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“…A low filling ratio is desirable, as the thermal resistance of the pool is generally higher than the resistance through the falling liquid film in the evaporator ( Fig. 2) [21]. The methanol volume was measured and introduced using a 30 cm 3 syringe and short length of vinyl tubing to avoid introducing air into the evacuated thermosyphon during the filling procedure.…”

Section: Thermosyphon Fabricationmentioning

confidence: 99%

“…5a, phon, which has a higher thermal resistance than the evaporating film on the walls above the pool (Fig. 2) [21].…”

Section: Steady State Operation Of Thermosyphon-assisted Cooling Systemmentioning

confidence: 99%

Thermosyphon-assisted cooling system for refrigeration applications

Mei

Longtin

2017

International Journal of Refrigeration

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Residential refrigeration is one of the largest contributors to home appliance energy consumption in the U.S. This energy use is nearly doubled if commercial refrigeration is included. By using cold outside temperatures for cooling, however, energy savings can be realized. In this work, a thermosyphon-assisted cooling system for a household refrigerator is presented. A single finned copper-tube thermosyphon with methanol as the working fluid is used. An environmental chamber that can reproduce outside ambient temperatures to-5 ºC is located above the refrigerator. Results are presented for different outside temperatures, fan speeds, and filling ratios in the thermosyphon. The electricity use for both the original equipment refrigeration and the thermosyphon system is reported. The interior temperature is found to vary depending on the number of fans that are used to blow air over the thermosyphon evaporator in the refrigerated space. This

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“…Hence, there has been a considerable research focused on developing better models to predict the heat transfer achievement for a given temperature difference. Experimental and theoretical studies were carried out by Shiraishi, M. et al [2]the heat transfer characteristics of a two-phase closed thermosyphon were studied experimentally and a simple mathematical model was developed to predict the performance of such two phase thermosyphon. Lin, L. et al [8] developed high performance miniature heat pipes for the cooling of high heat flux electronics using new capillary structures made of folded copper sheet fin.…”

Section: : Introductionmentioning

confidence: 99%

Comparison between a Heat Pipe and a Thermosyphon Performance with Variable Evaporator Length_ENG

Ahmad¹,

Yousif²

2013

(AREJ)

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Heat pipes and two phase thermosyphons are heat transfer devices whose operating principles are based on the evaporation/condensation of a working fluid using the capillary pumping forces (in the case of heat pipe) and gravity forces (in the case of two phase thermosyphons) to ensure the fluid circulation. The two systems were designed and constructed to investigate the performance and the affecting parameters, using ethanol as a working fluid. The affecting parameters which were studied are power input (200≤Q≤700) W, working fluid filling ratios (35% and 85%) and aspect ratio, the ratio of evaporator length to inner diameter, (4.0, 7.8 and11.5). The experimental results showed that the best performance of heat pipe obtained at aspect ratio (7.8) and (85%) filling ratio at (500) W where the maximum heat transfer coefficient was (9950) W/m 2. o C, while for the two phase thermosyphon the best performance was obtained at aspect ratio (4.0) for (35%) filling ratio and power input (600) W with maximum heat transfer coefficient equals to(4590) W/m 2. o C. The overall comparison between the two systems showed that the performance of the heat pipe is better than that of the two phase thermosyphon. The experimental results of heat pipe was compared with theoretical and empirical correlations showing reasonable agreement especially with immura with percent 70%.

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Investigation of heat transfer characteristics of a two-phase closed thermosyphon

Cited by 78 publications

References 3 publications

Experimental Investigation of the Thermal Performance of a Wickless Heat Pipe Operating with Different Fluids: Water, Ethanol, and SES36. Analysis of Influences of Instability Processes at Working Operation Parameters

Experimental Investigation of the Thermal Performance of a Wickless Heat Pipe Operating with Different Fluids: Water, Ethanol, and SES36. Analysis of Influences of Instability Processes at Working Operation Parameters

Thermosyphon-assisted cooling system for refrigeration applications

Comparison between a Heat Pipe and a Thermosyphon Performance with Variable Evaporator Length_ENG

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