An Experimental Investigation of Boiling Heat Transfer of Fluorocarbon R-11 Refrigerant for Concentric-Tube Thermosyphon

1981 ◽  
Vol 103 (3) ◽  
pp. 472-477 ◽  
Author(s):  
N. Seki ◽  
S. Fukusako ◽  
K. Koguchi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Experimental Investigation ◽  
Free Convection ◽  
Boiling Heat Transfer ◽  
Void Ratio ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Total Heat Flux ◽  
Controlling Variables

The characteristics of the boiling heat transfer for a concentric-tube open thermosyphon are examined in detail. Fluorocarbon R-11 refrigerant as a testing fluid is utilized. Out of a number of possible controlling variables, the effects of the heat flux, the void ratio, and the diametric ratio of the concentric-tube on the heat-transfer performance are determined. From the present experimental results it is demonstrated that total heat flux can be appropriately predicted by a superposition of the heat flux due to the available correlations for free convection and due to the correlations experimentally determined for boiling heat flux.

scholarly journals Microchannel Liquid-Cooled Heat Exchanger Based on a Nonuniform Lattice: Study on Structure Calculation, Formation Process, and Boiling Heat Transfer Performance

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7248
Author(s):  
Bo Qian ◽  
Hongri Fan ◽  
Gang Liu ◽  
Jianrui Zhang ◽  
Pei Li
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Heat Flux Density ◽  
Heat Transfer Performance ◽  
Lattice Structure ◽  
Flow Density ◽  
Transfer Performance ◽  
Heat Flow Density ◽  
Uniform Frames

A microchannel radiator is advantageous due to its high efficiency and large boiling heat transfer coefficient of two-phase flow. Based on the research of uniform lattice structures, this study proposed a microchannel heat exchanger with a nonuniform lattice structure. The calculation, optimal formation, and boiling heat transfer performance of the nonuniform lattice structure based on selective laser melting (SLM) were investigated, and heat exchange samples were successfully prepared using SLM. The porosity and pore morphology of the samples were analysed, and the contrast experiments of boiling heat transfer were conducted with deionised water. The results revealed that the heat flow density of the lattice structure was a minimum of 244% higher than that of the traditional liquid-cooled plate. The critical heat flux density of the lattice structure is 110 W∙cm−2, and the critical heat flux density of the traditional flat plate is 45 W∙cm−2. In addition, the effects of cell structures indicated that for frame cells, the heat transfer effect of nonuniform frames was inferior to that of uniform frames; for face-centred cubic (FCC) cells, the nonuniform and uniform frames exhibited the same trend. However, the heat flow density of FCC cells was 25% higher than that of frame structures.

Nanofluid Boiling Heat Transfer and Critical Heat Flux Enhancement: Mechanism to Be Revealed

2013 ◽  
Author(s):  
Junmei Wu ◽  
Jiyun Zhao ◽  
Yun Wang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Bubble Dynamics ◽  
High Heat ◽  
Solid Particles ◽  
High Heat Flux ◽  
Transfer Performance

As a novel strategy to improve heat transfer characteristics of fluids by the addition of solid particles with diameters below 100 nm, nanofluids exhibits unprecedented heat transfer properties and are being considered as potential working fluids to be used in high heat flux systems such as nuclear reactors, electronic cooling systems and solar collectors. The present paper reviews the state-of-the-art studies on nanofluid boiling heat transfer performance and critical heat flux (CHF) enhancement. It is found that some results on nanofluids boiling heat transfer performance are inconsistent or contradictory in data published. The knowledge on the mechanism of nanofluids boiling CHF enhancement is insufficient. Bubble dynamics of nanofluids boiling is suggested to be investigated to identify the exact contributions of solid surface modifications and suspended nanoparticles to CHF enhancement in nanofluids boiling heat transfer.

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