scholarly journals Discussion: “Mass Flux and Enthalpy Distribution in a Rod Bundle for Single- and Two-Phase Flow Conditions” (Lahey, Jr., R. T., Shiralkar, B. S., and Radcliffe, D. W., 1971, ASME J. Heat Transfer, 93, pp. 197–206)

1971 ◽  
Vol 93 (2) ◽  
pp. 207-208
Author(s):  
R. W. Bowring
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Rod Bundle

Mass Flux and Enthalpy Distribution in a Rod Bundle for Single- and Two-Phase Flow Conditions

1971 ◽  
Vol 93 (2) ◽  
pp. 197-206 ◽  
Author(s):  
R. T. Lahey ◽  
B. S. Shiralkar ◽  
D. W. Radcliffe
Keyword(s):  
Mass Flux ◽  
Operating Conditions ◽  
Boiling Water ◽  
Flow Diversion ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Water Reactor ◽  
Rod Bundle ◽  
Natural Flow

Diabatic multirod subchannel data have been obtained in a 9-rod bundle for operating conditions typical of a boiling water reactor. These data have been used to obtain both the natural flow and enthalpy distribution in a rod bundle and information on the flow diversion enthalpy and the effective flow diversion length.

EFFECTS OF SYSTEM PARAMETERS ON THE TWO-PHASE FLOW AND HEAT TRANSFER BEHAVIOR IN A ROD BUNDLE

2019 ◽  
Author(s):  
Grant Garrett ◽  
Faith R. Beck ◽  
Yue Jin ◽  
Fan Bill Cheung ◽  
Stephen M. Bajorek ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
System Parameters ◽  
Rod Bundle ◽  
Flow And Heat Transfer ◽  
Heat Transfer Behavior ◽  
Transfer Behavior

Impact of Channel Geometry on Two-Phase Flow Heat Transfer Characteristics of Refrigerants in Microchannel Heat Exchangers

1998 ◽  
Vol 120 (2) ◽  
pp. 485-491 ◽  
Author(s):  
T. S. Ravigururajan
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Heat ◽  
The Heat Transfer Coefficient

Microchannel surfaces, often machined to 20 to 1000 μm in width and depth, are employed in high-heat-flux applications. However, a large number of variables, control the two-phase flow heat transfer coefficient. The pressure, the surface heat flux, and the mass flux significantly affect the thermal transport. Experiments were conducted on a setup that was built for testing microchannel heat exchanges. The parameters considered in the study are power input: 20 to 300 W, volume flow rate: 35 to 300 ml/min, quality: 0 to 0.5, inlet subcooling: 5 to 15°C. The results indicate that the heat transfer coefficient and pressure drop are functions of the flow quality, the mass flux, and, of course, the heat flux and the related surface superheat. The heat transfer coefficient decreases from a value of 12,000 W/m2-K to 9000, W/m2-K at 80°C, when the wall superheat is increased from 10 to 80°C. The coefficient decreases by 30 percent when the exit vapor quality is increased from 0.01 to 0.65.

Two-Phase Flow Patterns During Microchannel Vaporization of CO2 at Near-Critical Pressures

2003 ◽  
Author(s):  
Jostein Pettersen
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Mass Flux ◽  
Two Phase Flow ◽  
Bubble Formation ◽  
Glass Tube ◽  
Flow Patterns ◽  
High Mass ◽  
Phase Flow ◽  
Two Phase

Carbon dioxide (CO2 / R-744) is receiving renewed interest as a refrigerant, in many cases based on systems with microchannel heat exchangers that have high pressure capability, efficient heat transfer, and compact design. A good understanding of two-phase flow of evaporating CO2 in microchannels is needed to analyze and predict heat transfer. A special test rig was built in order to observe two-phase flow patterns, using a horizontal quartz glass tube with ID 0.98 mm, externally coated by a transparent resistive film. Heat flux was obtained by applying DC power to the film, and flow patterns were recorded at 4000 or 8000 frames per second by a digital video camera. Flow patterns were recorded for temperatures 20°C and 0°C, and for mass flux ranging from 100 to 580 kgm−2s−1. The observations showed a dominance of intermittent (slug) flow at low x, and wavy annular flow with entrainment of droplets at higher x. At high mass flux, the annular/entrained flow pattern could be described as dispersed. The aggravated dryout problem reported from heat transfer experiments at high mass flux could be explained by increased entrainment. Stratified flow was not observed in the tests with heat load. Bubble formation and growth could be observed in the liquid film, and the presence of bubbles gave differences in flow pattern compared to adiabatic flow. The flow pattern observations did not fit generalized maps or transition lines showed in the literature.

Investigation of pre- and post-dryout heat transfer of steam-water two-phase flow in a rod bundle

1987 ◽  
Vol 102 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Hiroshige Kumamaru ◽  
Yasuo Koizumi ◽  
Kanji Tasaka
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Rod Bundle
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