EXPERIMENTAL INVESTIGATION OF CRITICAL HEAT FLUX IN FORCED CONVECTION BOILING OF FREON IN A TUBE AT HIGH SUBCRITICAL PRESSURE

1982 ◽  
Author(s):  
K. Nishikawa ◽  
Suguru Yoshida ◽  
A. Yamada ◽  
Masaki Ohno
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Forced Convection ◽  
Critical Heat Flux

THE CALCULATION OF CRITICAL HEAT FLUX IN FORCED CONVECTION BOILING

1974 ◽  
Author(s):  
P. B. Whalley ◽  
P. Hutchinson ◽  
Geoffrey F. Hewitt
Keyword(s):  
Heat Flux ◽  
Forced Convection ◽  
Critical Heat Flux

Combined Pressure and Subcooling Effects on Pool Boiling From a PPGA Chip Package

1997 ◽  
Vol 119 (2) ◽  
pp. 95-105 ◽  
Author(s):  
A. A. Watwe ◽  
A. Bar-Cohen ◽  
A. McNeil
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Critical Heat Flux ◽  
Pool Boiling ◽  
Combined Effects ◽  
Minimal Effect ◽  
Nucleate Pool Boiling ◽  
Lower Wall ◽  
Saturated Liquid

This study presents a detailed experimental investigation of the combined effects of pressure and subcooling on nucleate pool boiling and critical heat flux (CHF) for degassed fluorocarbon FC-72 boiling on a plastic pin-grid-array (PPGA) chip package. In these experiments pressure was varied between 101.3 and 303.9 kPa and the subcooling ranged from 0 to 65°C. As expected, lower wall superheats resulted from increases in pressure, while subcooling had a minimal effect on fully developed pool boiling. However, the superheat reductions and CHF enhancements were found to be smaller than those predicted by existing models. The CHF for saturated liquid conditions increased by nearly 17 percent for an increase in pressure from 101.3 to 202.7 kPa. In experiments with both FC-72 and FC-87 further increases in pressure did not produce any significant increase in CHF. At a pressure of 101.3 kPa a subcooling of 30°C increased CHF on horizontal upward-facing chips by approximately 50 percent, as compared to 70 percent on vertically oriented packages. The enhancement in CHF due to subcooling decreased rapidly with increasing pressure, and the data showed that the influence of pressure and subcooling on CHF is not additive. A correlation to predict pool boiling CHF under the combined effects of pressure and subcooling is proposed.

Experimental Investigation of Critical Heat Flux in Microchannels for Flow-Field Probes

2009 ◽  
Author(s):  
Ali Kos¸ar ◽  
Yoav Peles ◽  
Arthur E. Bergles ◽  
Gregory S. Cole
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Critical Heat Flux ◽  
Mass Velocity ◽  
Thermal Condition ◽  
Average Error ◽  
New Correlation ◽  
Hydraulic Conditions ◽  
Data Points ◽  
Heated Length

Critical heat flux (CHF) of water in circular stainless steel microchannels with inner diameters ranging from ∼127μm to ∼254 μm was investigated. Forty-five CHF data points were acquired over mass velocities ranging from 1,200 kg/m2s to 53,000 kg/m2s, heated lengths from 2 cm to 8 cm, and exit qualities from −0.2 to 0.15. Most of the exit qualities fell below 0.1. It was found that CHF conditions were more dependent on mass velocity and heated length than on exit thermal condition. The results were also compared to six CHF correlations, with a mean average error ranging from 22% to 261.8%. A new correlation was proposed to better predict the critical heat flux data under the thermal-hydraulic conditions studied in this investigation. In developing the correlation, 319 data points were added from two previous studies.

Effect of Channel Blockage on Critical Heat Flux for a Horizontal Cylinder in Crossflow

1995 ◽  
Vol 117 (4) ◽  
pp. 998-1002 ◽  
Author(s):  
R. Dowlati ◽  
M. Kawaji ◽  
I. D. Sardjono ◽  
S. T. Revankar
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Critical Heat Flux ◽  
Horizontal Tube ◽  
Horizontal Cylinder ◽  
Fluid Velocities ◽  
Wide Range ◽  
Channel Blockage ◽  
Flow Blockage

An experimental investigation has been conducted on critical heat flux (CHF) on a horizontal tube in crossflow boiling R-113 at near atmospheric pressures. Data were obtained over a range of fluid velocities (up to 0.52 m/s), heater diameters (8 to 12.7 mm), and flow blockage factors (D/H = 0.31 to 0.5). The effect of the flow blockage on CHF was examined in detail and compared with other data and existing correlations. No significant effect of flow blockage was observed for D/H up to 0.5. An analytical modification of the Katto-Haramura CHF correlation is proposed to take into account the effect of flow blockage over a wide range of D/H.

Sign in / Sign up

Export Citation Format

Share Document