Film Boiling on Downward Facing Flat Plates With Varying Inclination Angles

2005 ◽  
Author(s):  
Chan S. Kim ◽  
Mong J. Yu ◽  
Kune Y. Suh ◽  
Joy L. Rempe ◽  
F. Bill Cheung ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Flat Surface ◽  
Flow Direction ◽  
Film Boiling ◽  
Transfer Coefficients ◽  
Flat Plates ◽  
Heat Transfer Coefficients ◽  
Inclination Angles ◽  
Water Test

The effect of inclination angle of the downward facing flat plate on the interfacial wavy motion is investigated utilizing the water test apparatus DELTA FS (Downward Ebullient Laminar Transition Apparatus Flat Surface) in a quasi-steady state. Film boiling heat transfer coefficients are obtained on the relatively long surface in the flow direction. The measured heat transfer coefficients are compared with those predicted by the laminar film boiling and interfacial wavy film boiling correlations at the same experimental condition. Visualization of the vapor film revealed that the interfacial wavelength decreases as the flat plate moves from the vertical to downward facing locations.

Angular Dependency on Film Boiling Heat Transfer From Relatively Long Inclined Flat Plates

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Chan Soo Kim ◽  
Kune Y. Suh
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Boiling Heat Transfer ◽  
Flow Direction ◽  
Film Boiling ◽  
Transfer Coefficients ◽  
Flat Plates ◽  
Heat Transfer Coefficients ◽  
Inclination Angles ◽  
Angular Dependency

The effect of inclination angle of the downward facing flat plate on the interfacial wavy motion is investigated utilizing the water quenching test apparatus downward ebullient laminar transition apparatus flat surface (DELTA-FS) in a quasi-steady state. Film boiling heat transfer coefficients are obtained on the relatively long surface in the flow direction. Interfacial velocities at the various inclination angles and wall superheat conditions are determined through the analysis of the visualized continuous snapshots with 1000 fps. Visualization of the vapor film reveals that the interfacial wavelength increases and the interfacial velocity decreases as the flat plate moves from the vertical to downward facing locations. A new semi-empirical correlation is developed from the measured heat transfer coefficients and interfacial velocities. The correlation shows good agreement with the previous water test results on vertical plates. In the case of the previous other fluid experimental results on the vertical plates, the correlation overpredicts the film boiling heat transfer coefficients at the experimental condition.

Local Heat Transfer to Staggered Arrays of Impinging Circular Air Jets

1983 ◽  
Vol 105 (2) ◽  
pp. 354-360 ◽  
Author(s):  
A. I. Behbahani ◽  
R. J. Goldstein
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flat Plate ◽  
Flow Direction ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Air Jets ◽  
Impingement Surface

Measurements are made of the local heat transfer from a flat plate to arrays of impinging circular air jets. Fluid from the spent jets is constrained to flow out of the system in one direction. Two different jet-to-jet spacings, 4 and 8 jet diameters, are employed. The parameters that are varied include jet-orifice-plate to impingement-surface spacing and jet Reynolds number. Local heat transfer coefficients vary periodically both in the flow direction and across the span with high values occurring in stagnation regions. Stagnation regions of individual jets as determined by local heat transfer coefficients move further in the downstream direction as the amount of crossflow due to upstream jet air increases. Local heat transfer coefficients are averaged numerically to obtain spanwise and streamwise-spanwise averaged heat transfer coefficients.

Impingement Cooling Experiments With Flat Plate and Pin Plate Target Surfaces

1999 ◽  
Author(s):  
Rainer Hoecker ◽  
Bruce V. Johnson ◽  
Josef Hausladen ◽  
Matthias Rothbrust ◽  
Bernhard Weigand
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Copper Plate ◽  
Orifice Plate ◽  
Plate Model ◽  
Transfer Coefficients ◽  
Flat Plates ◽  
Target Plate ◽  
Average Heat ◽  
Heat Transfer Coefficients

Heat transfer experiments were conducted with three (3) different target plate configurations: a baseline copper flat smooth plate, a copper plate model with copper pins and a copper plate model with Teflon pins, to determine average heat transfer coefficients on the flat and pin surfaces for application with different plate materials. For each target plate surface configuration, the heat transfer experiments were conducted with selected impingement orifice plate configurations and with selected spacing between the orifice plate and the heat transfer target plate. The heat transfer results for the baseline copper smooth flat plate were in good agreement with a well-recognized correlation for the flow regions used in the correlation. An analytical procedure, similar to that used by Metzger et al. for pin-fins in coolant channels, was developed to separate the average heat transfer coefficients on the flat and pin surfaces. The results with the copper pins showed modest increases of approximately 35 percent in heat transfer at lower Reynolds numbers, decreasing with increased Reynolds number. Application of the experimental results to an analysis for high-pressure engine conditions with modest thermal conductivity materials showed that the overall heat transfer coefficient can decrease with pin surfaces for some conditions, compared to flat plates.

scholarly journals Local Heat Transfer to Staggered Arrays of Impinging Circular Air Jets

1982 ◽  
Author(s):  
A. I. Behbahani ◽  
R. J. Goldstein
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flat Plate ◽  
Flow Direction ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Air Jets ◽  
Impingement Surface

Measurements are made of the local heat transfer from a flat plate to impinging arrays of staggered circular air jets. Fluid from the spent jets is constrained to flow out in one direction. Two different jet-to-jet spacings, 4 and 8 jet diameters, are employed. The parameters that are varied include jet-orifice-plate to impingement-surface spacing and jet Reynolds number. Local heat transfer coefficients vary periodically both in the flow direction and across the span with high values occurring at stagnation regions. Stagnation regions of individual jets as determined by local heat transfer coefficients move further in the downstream direction as the amount of crossflow due to upstream jet air increases. Local heat transfer coefficients are averaged numerically to obtain spanwise and streamwise-spanwise averaged heat transfer coefficients.

scholarly journals Heat Transfer in Rotating Serpentine Passages With Trips Normal to the Flow

1992 ◽  
Vol 114 (4) ◽  
pp. 847-857 ◽  
Author(s):  
J. H. Wagner ◽  
B. V. Johnson ◽  
R. A. Graziani ◽  
F. C. Yeh
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Large Scale ◽  
Flow Direction ◽  
Operating Conditions ◽  
Transfer Model ◽  
Transfer Coefficients ◽  
Flow Equations ◽  
Turbine Blade Cooling ◽  
Heat Transfer Coefficients

Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large-scale, multipass, heat transfer model with both radially inward and outward flow. Trip strips on the leading and trailing surfaces of the radial coolant passages were used to produce the rough walls. An analysis of the governing flow equations showed that four parameters influence the heat transfer in rotating passages: coolant-to-wall temperature ratio, Rossby number, Reynolds number, and radius-to-passage hydraulic diameter ratio. The first three of these four parameters were varied over ranges that are typical of advanced gas turbine engine operating conditions. Results were correlated and compared to previous results from stationary and rotating similar models with trip strips. The heat transfer coefficients on surfaces, where the heat transfer increased with rotation and buoyancy, varied by as much as a factor of four. Maximum values of the heat transfer coefficients with high rotation were only slightly above the highest levels obtained with the smooth wall model. The heat transfer coefficients on surfaces where the heat transfer decreased with rotation, varied by as much as a factor of three due to rotation and buoyancy. It was concluded that both Coriolis and buoyancy effects must be considered in turbine blade cooling designs with trip strips and that the effects of rotation were markedly different depending upon the flow direction.

The Effects of Nucleate Boiling Versus Film Boiling on Heat Transfer in Power Boiler Tubes

1962 ◽  
Vol 84 (4) ◽  
pp. 365-371 ◽  
Author(s):  
H. S. Swenson ◽  
J. R. Carver ◽  
G. Szoeke
Keyword(s):  
Heat Transfer ◽  
Nucleate Boiling ◽  
Steel Tube ◽  
Heat Fluxes ◽  
Inside Surface ◽  
Film Boiling ◽  
Stainless Steel Tube ◽  
Transfer Coefficients ◽  
Steam Quality ◽  
Heat Transfer Coefficients

In large, subcritical pressure, once-through power boilers heat is transferred to steam and water mixtures ranging in steam quality from zero per cent at the bottom of the furnace to 100 per cent at the top. In order to provide design information for this type of boiler, heat-transfer coefficients for forced convection film boiling were determined for water at 3000 psia flowing upward in a vertical stainless-steel tube, AISI Type 304, having an inside diameter of 0.408 inches and a heated length of 6 feet. Heat fluxes ranged between 90,000 and 180,000 Btu/hr-sq ft and were obtained by electrical resistance heating of the tube. The operation of the experimental equipment was controlled so that nucleate boiling, transition boiling, and stable film boiling occurred simultaneously in different zones of the tube. The film boiling data were correlated with a modified form of the equation Nu = a a(Re)m(Pr)n using steam properties evaluated at inside surface temperature. Results of a second series of heat-transfer tests with tubes having a helical rib on the inside surface showed that nucleate boiling could be maintained to much higher steam qualities with that type of tube than with a smooth-bore tube.

Sign in / Sign up

Export Citation Format

Share Document