A study of the fundamental operations of a capillary driven heat transfer device in both normal and low gravity Part 1. Liquid slug formation in low gravity

1998 ◽  
Author(s):  
Jeffrey S. Allen ◽  
Kevin Hallinan ◽  
Jack Lekan
2010 ◽  
Vol 240 (10) ◽  
pp. 2409-2414 ◽  
Author(s):  
Piyush Sabharwall ◽  
Mike Patterson ◽  
Vivek Utgikar ◽  
Fred Gunnerson

2013 ◽  
Vol 112 ◽  
pp. 576-591 ◽  
Author(s):  
John Kaiser Calautit ◽  
Ben Richard Hughes ◽  
Hassam Nasarullah Chaudhry ◽  
Saud Abdul Ghani

Author(s):  
Leonard Vasiliev ◽  
Alexander Zhuravlyov ◽  
Maxim Kuzmich ◽  
Vadzim Kulikouski

1979 ◽  
Vol 50 (9) ◽  
pp. 5682-5685 ◽  
Author(s):  
Milivoj Belić ◽  
Joel I. Gersten

Author(s):  
Olubunmi Popoola ◽  
Ayobami Bamgbade ◽  
Yiding Cao

An effective design option for a cooling system is to use a two-phase pumped cooling loop to simultaneously satisfy the temperature uniformity and high heat flux requirements. A reciprocating-mechanism driven heat loop (RMDHL) is a novel heat transfer device that could attain a high heat transfer rate through a reciprocating flow of the two-phase working fluid inside the heat transfer device. Although the device has been tested and validated experimentally, analytical or numerical study has not been undertaken to understand its working mechanism and provide guidance for the device design. The objective of this paper is to develop a numerical model for the RMDHL to predict its operational performance under different working conditions. The developed numerical model has been successfully validated by the existing experimental data and will provide a powerful tool for the design and performance optimization of future RMDHLs. The study also reveals that the maximum velocity in the flow occurs near the wall rather than at the center of the pipe, as in the case of unidirectional steady flow. This higher velocity near the wall may help to explain the enhanced heat transfer of an RMDHL.


Author(s):  
Yiding Cao ◽  
Mingcong Gao

This paper introduces a novel heat transfer mechanism that facilitates two-phase heat transfer while eliminating the so-called cavitation problem commonly encountered by a conventional pump. The heat transfer device is coined as the reciprocating-mechanism driven heat loop (RMDHL), which includes a hollow loop having an interior flow passage, an amount of working fluid filled within the loop, and a reciprocating driver. The hollow loop has an evaporator section, a condenser section, and a liquid reservoir. The reciprocating driver is integrated with the liquid reservoir and facilitates a reciprocating flow of the working fluid within the loop, so that liquid is supplied from the condenser section to the evaporator section under a substantially saturated condition and the so-called cavitation problem associated with a conventional pump is avoided. The reciprocating driver could be a solenoid-operated reciprocating driver for electronics cooling applications and a bellows-type reciprocating driver for high-temperature applications. Experimental study has been undertaken for a solenoid-operated heat loop in connection with high heat flux thermal management applications. Experimental results show that the heat loop worked very effectively and a heat flux as high as 300 W/cm2 in the evaporator section could be handled. The applications of the bellows-type reciprocating heat loop for gas turbine nozzle guide vanes and the leading edges of hypersonic vehicles are also illustrated. The new heat transfer device is expected to advance the current two-phase heat transfer device and open up a new frontier for further research and development.


Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake ◽  
Tomonari Yamada

Boiling heat transfer of thin-rectangular channels of the width of 10 mm has been examined. The height of the flow channel was in a range from 0.6 mm to 0.4 mm. Experimental fluid was water. Bubbly flow, slug flow, semi annular flow and annular flow were observed. The flow pattern transition agreed well with the Baker flow pattern map for the usual sized flow path. The critical heat flux was lower than the value of the usual sized flow channel. The Koizumi and Ueda method predicted well the trend of the critical heat flux of the present experiments. At the critical heat flux condition, the heat transfer surface was covered by liquid slug, a large bubble pushed away the liquid slug, a dry area was formed on the heat transfer surface and then liquid slug came around to cover the heat transfer surface again. This process repeated rapidly. Following this observation, a heat transfer surface temperature calculation model at the critical heat flux condition was proposed. The calculated result re produced the experimental result.


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