A Mesoscale Electrohydrodynamic-Driven Two-Phase Flow Heat Transport Device in Circular Geometry and In-Tube Boiling Heat Transfer Coefficient Under Low Mass Flux

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Viral K. Patel ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Heat Transport ◽  
Boiling Heat Transfer ◽  
Two Phase Flow ◽  
Phase System ◽  
Phase Flow ◽  
Two Phase ◽  
Boiling Heat Transfer Coefficient ◽  
Low Mass ◽  
Flow Heat ◽  
Transport Device

Meso and microscale two-phase flow heat transport involves devices that are used to remove heat from small surface areas by circulating a working fluid through the heated space and causing phase change from liquid to vapor. There is an impetus to develop such devices for applications that require compact thermal management systems. The active, mesoscale two-phase flow heat transport device presented in this paper is driven solely by electrohydrodynamic (EHD) conduction pumping, and its heat transport characteristics are provided. An important understanding of the EHD conduction pump performance under a two-phase system versus single-phase system is also elucidated from these results. In addition, the ability to generate reliable low mass fluxes by this method has also allowed for determining local in-tube flow boiling heat transfer coefficient as a function of vapor quality in a mesoscale circular tube evaporator, providing limited but valuable information currently unavailable in the literature.

Micro-Scale Two-Phase Flow Heat Transport Device Driven by Electrohydrodynamic Conduction Pumping

2013 ◽  
Author(s):  
Viral K. Patel ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Heat Transport ◽  
Two Phase Flow ◽  
Operating Conditions ◽  
Electrode Spacing ◽  
Working Fluid ◽  
Phase Flow ◽  
Two Phase ◽  
Micro Scale ◽  
Flow Heat ◽  
Transport Device

Micro-scale two-phase flow heat transport involves specialized devices that are used to remove large amounts of heat from small surface areas. They operate by circulating a working fluid through a heated space which causes phase change from liquid to vapor. During this process, a significant amount of heat is transported away from the heat source. Micro-scale heat transport devices are compact in size and the heat transfer coefficient can be orders of magnitude higher than in macro-scale for similar operating conditions. Thus, it is of interest to develop such devices for cooling of next-generation electronics and other applications with extremely large heat fluxes. The heat transport device presented in this paper is driven by electrohydrodynamic (EHD) conduction pumping. In EHD conduction pumping, when an electric field is applied to a dielectric liquid, flow is induced. The pump is installed in a two-phase flow loop and has a circular 1 mm diameter cross section with electrode spacing on the order of 120 μm. It acts to circulate the fluid in the loop and has a simple yet robust, non-mechanical design. Results from two-phase flow experiments show that it is easily controlled and such electrically driven pumps can effectively be used in heat transport systems.

Design and Performance of Two-Phase Flow Heat Transfer Experiment Platform Using R134a as Working Fluid

2010 ◽  
Author(s):  
Chang-Nian Chen ◽  
Ji-Tian Han ◽  
Li Shao ◽  
Tien-Chien Jen ◽  
Yi-Hsin Yen
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Two Phase Flow ◽  
Working Fluid ◽  
Phase Flow ◽  
Heat Transfer Characteristics ◽  
Transfer Experiment ◽  
Two Phase ◽  
Experiment Platform ◽  
Flow Heat

A two-phase flow heat transfer experiment platform using alternative refrigerant R134a as working fluid was designed and built to investigate the characteristics of two-phase flow heat transfer. It was primarily made up of circle power, heating/cooling sources, parallel test sections, accumulator and data acquisition system. The working loop was designed for performance pressure of 1.6 MPa and temperature of 200°C, preheated section power of 24 V × 300 A and test section of 60 V × 500 A. The refrigeration chilling unit had a maximum output of 50 kW. The preheated and test section were designed as horizontal helically-coiled tubes, and a visual reservoir made of electric melting-quartz glass was designed to observe flow patterns intuitively. Technology and methods related to fluid and mechanics were discussed in this paper including the aspects of materials and welding, sealing and heat preservation, special machining and accessories installation etc. Pressure testing, heat balance testing, heat transfer characteristics experiments were performed under various conditions to analyze the usability and stability of this platform. Test results showed that the leak ratio was no more than 250 Pa/h at 2.0 MPa and the heat loss of the system wrapped with PEF materials was less than 5%. Under the conditions of pressures of 0.30–0.95 MPa, mass fluxes of 120–620 kg/m2s, inlet qualities of −0.08–0.38 and heated power of 0.45–1.30 kW, R134a two-phase flow boiling heat transfer characteristics were investigated and discussed in detail. This platform can be used for studying the characteristics of two-phase flow pressure drop, boiling heat transfer and fluid-to-fluid modeling technique etc.

scholarly journals Evaluation of Correlations of Flow Boiling Heat Transfer of R22 in Horizontal Channels

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Zhanru Zhou ◽  
Xiande Fang ◽  
Dingkun Li
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Phase Flow ◽  
Two Phase ◽  
Absolute Deviation ◽  
Flow Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient ◽  
Data Points

The calculation of two-phase flow boiling heat transfer of R22 in channels is required in a variety of applications, such as chemical process cooling systems, refrigeration, and air conditioning. A number of correlations for flow boiling heat transfer in channels have been proposed. This work evaluates the existing correlations for flow boiling heat transfer coefficient with 1669 experimental data points of flow boiling heat transfer of R22 collected from 18 published papers. The top two correlations for R22 are those of Liu and Winterton (1991) and Fang (2013), with the mean absolute deviation of 32.7% and 32.8%, respectively. More studies should be carried out to develop better ones. Effects of channel dimension and vapor quality on heat transfer are analyzed, and the results provide valuable information for further research in the correlation of two-phase flow boiling heat transfer of R22 in channels.

Analysis of the two-phase flow, heat transfer, and instability characteristics in a loop thermosyphon

2021 ◽  
Vol 79 (9) ◽  
pp. 656-680
Author(s):  
Yun Liu ◽  
Zhigang Li ◽  
Yuyan Jiang ◽  
Cong Guo ◽  
Dawei Tang
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Heat
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