An Experimental Study of Flow Boiling Heat Transfer in Rib-Roughened Tube Annuli

1995 ◽  
Vol 117 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Shou-Shing Hsieh ◽  
Mao-Yu Wen
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Suppression Factor ◽  
Two Phase ◽  
Geometric Configurations ◽  
Flow Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient ◽  
Two Phases ◽  
R 114

Heat transfer measurements were performed on six rib-type roughened tube annuli (4.67–9.01 mm Dh, 6–16 ribs, rib pitch 19.7–63.0 mm, rib height 4 ram, rib width 15 mm, rib angle 20–60 deg) with two phases of refrigerant R-114 under evaporating conditions. Based on the same heat transfer area of the test section, the effects of heat flux, quality, and rib spacing on flow boiling heat transfer coefficient were presented and discussed. Correlations of two-phase enhancement factor F and suppression factor S were developed by modifications and extensions of Chen’s model for the present geometric configurations.

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.

scholarly journals Supercapillary Architecture‐Activated Two‐Phase Boundary Layer Structures for Highly Stable and Efficient Flow Boiling Heat Transfer

2019 ◽  
Vol 32 (2) ◽  
pp. 1905117 ◽  
Author(s):  
Wenming Li ◽  
Zuankai Wang ◽  
Fanghao Yang ◽  
Tamanna Alam ◽  
Mengnan Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Phase Boundary ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Two Phase ◽  
Layer Structures ◽  
Flow Boiling Heat Transfer

Experiment on Flow Boiling Heat Transfer in Tube and Study of Performance of a Vacuum Solar Collector

2007 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Masahiro Taniguchi ◽  
Shunsaku Nakauchi ◽  
Tadayoshi Tanaka
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Boiling Heat Transfer ◽  
Solar Collector ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Collector Plate ◽  
Flow Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient ◽  
Inclined Angle

A high-vacuum solar collector system with flow boiling in tube has high collector efficiency of solar energy. In this paper flow boiling heat transfer coefficient in tube was measured by changing mass flow rate (30–80 kg/m2s), heat flux (5–30 kW/m2) and inclined angle of collector plate. Inside diameter of tube is 4.4 mm, and saturation temperature is 100°C. Flow boiling heat transfer coefficient is about 8000 W/m2K and decreases at low flow rate. Effect of the inclined angle of collector plate is small. Experimental results of boiling heat transfer coefficients are similar to Sani’s correlation equation. The collector efficiency of vacuum solar collector systems with flow boiling in tube is analyzed and the efficiency is 69% at a standard calculation condition. There is 50°C temperature difference in the collector plate. Effects of the mass flow rate and the vacuum pressure on the efficiency are large. The efficiency decreases at high saturation temperature and at low solar radiation.

Experimental Study of Flow Boiling Heat Transfer Coefficient of FC-72 Over Micro-Pin-Finned Surfaces

2010 ◽  
Author(s):  
Y. F. Xue ◽  
M. Z. Yuan ◽  
J. J. Wei
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Fluid Velocity ◽  
Nucleate Boiling ◽  
Flow Boiling Heat Transfer ◽  
Nucleate Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

Experiments of flow boiling heat transfer coefficient of FC-72 were carried out over simulated silicon chip of 10×10×0.5 mm3 for electronic cooling. Four kinds of micro-pin-fins with the dimensions of 30×60, 30×120, 50×60, 50×120 μm2 (thickness, t × height, h) respectively, were fabricated on the chip surfaces by the dry etching technique to enhance boiling heat transfer. A smooth chip was also tested for comparison. The experiments were conducted at three different fluid velocities (0.5, 1 and 2m/s) and three different liquid subcoolings (15, 25 and 35K). All micro-pin-finned surfaces show a considerable heat transfer enhancement compared to the smooth surface. Both the forced convection and nucleate boiling heat transfer contribute to the total heat transfer performance. The contribution of each factor to the total heat transfer has been clearly presented in the flow boiling heat transfer coefficient curves. In a lower heat flux region, the heat transfer coefficient increases greatly with increasing fluid velocity, but increases slightly with increasing heat flux, indicating that the single-phase forced convection dominates the heat transfer process. With further increasing heat flux to the onset of nucleate boiling, the heat transfer coefficient increases remarkably. For a given liquid subcooling, the curves of flow boiling heat transfer coefficient at fluid velocities of 0.5 and 1 m/s almost follow one line for each surface, showing insensitivity of nucleate boiling heat transfer to fluid velocity. However, at the largest fluid velocity of 2 m/s, the slope of the flow boiling heat transfer coefficient curves for micro-pin-finned surfaces becomes smaller, indicating that the forced convection also plays an important role besides the nucleate boiling heat transfer. The curves of the flow boiling heat transfer coefficient can be used to determine the boiling incipience at different fluid velocities, which provides a basis for the suitable fluid velocity selection in designing highly efficient cooling scheme for electronic devices.

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