scholarly journals Time and Space Resolved Heat Transfer Measurements Under Nucleate Bubbles With Constant Heat Flux Boundary Conditions

2003 ◽  
Author(s):  
Jerry G. Myers ◽  
Sam W. Hussey ◽  
Glenda F. Yee ◽  
Jungho Kim
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Characteristic Length ◽  
Pool Boiling ◽  
Constant Heat Flux ◽  
Time And Space ◽  
Constant Heat ◽  
Transfer Data ◽  
Flux Boundary Conditions ◽  
Transfer Mechanisms

Investigations into single bubble pool boiling phenomena are often complicated by the difficulties in obtaining time and space resolved information in the bubble region. This usually occurs because the heaters and diagnostics used to measure heat transfer data are often on the order of, or larger than, the bubble characteristic length or region of influence. This has contributed to the development of many different and sometimes contradictory models of pool boiling phenomena and dominant heat transfer mechanisms.

Natural Convection Local Heat Transfer on Constant-Heat-Flux Inclined Surfaces

1969 ◽  
Vol 91 (4) ◽  
pp. 511-516 ◽  
Author(s):  
G. C. Vliet
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Natural Convection ◽  
Plate Theory ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Transfer Data ◽  
Inclined Surfaces

Experimental local heat transfer data are presented for natural convection on constant-heat-flux inclined surfaces using water and air. The data extend to Grz* Pr = 1016, cover angles from the vertical to 30 deg with the horizontal, and include the laminar, transition, and turbulent regimes. In the laminar regime the data correlate well with vertical plate theory when the gravitational component parallel to the surface is used. Transition is strongly affected by inclination, the transition Grz* Pr decreasing from near 1013 for vertical surfaces to approximately 108 for a surface at 30 deg to the horizontal. The turbulent local heat transfer data correlate using the actual gravity rather than the parallel component, and indicates a change in the Grz* Pr exponent from near 0 22 for a vertical surface to approximately 1/4 as the inclination decreases. The turbulent data can be correlated quite well by Nuz = 0.30(Grz* Pr)0.24.

Laminar Entropy Generation Over a Flat Plate With Isothermal and Constant Heat Flux Boundary Conditions Using the Von Ka´rma´n Integral Method

Volume 1 ◽  
2004 ◽  
Author(s):  
Eric B. Ratts ◽  
J. Steven Brown
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boundary Conditions ◽  
Flat Plate ◽  
Entropy Generation ◽  
Single Phase ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Fundamental Study ◽  
Flux Boundary Conditions

This paper is a fundamental study on the irreversibility of single-phase laminar convective heat transfer over a flat plate with isothermal and constant heat flux boundary conditions. It quantifies the losses due to viscous momentum transfer losses and heat transfer losses and presents the irreversibility of the convective flow based on the entropy generation (EG) method. This paper determines the entropy generation for incompressible, single phase, laminar flow for large and small Prandtl numbers over a flat plate with isothermal and constant heat flux boundary conditions using von Ka´rma´n’s integral theory.

Heat Transfer Investigation in a Smooth Rotating Channel With Thermography Liquid Crystal

2016 ◽  
Author(s):  
Ruquan You ◽  
Haiwang Li ◽  
Zhi Tao ◽  
Kuan Wei
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Rotation Number ◽  
Turning Point ◽  
Constant Heat Flux ◽  
Two Dimensional ◽  
Constant Heat ◽  
Rotation Numbers ◽  
Flux Boundary Conditions ◽  
Rotating Channel

An experiment investigation was conducted in a smooth cooling channel under rotating conditions on a new rotating facility. The heat transfer phenomenon of rotating channel with constant heat flux boundary conditions was measured using PIV and TLCs (Thermography Liquid Crystal). The square cross-section channel is manufactured from Plexiglas. Four 1 mm thick transparent ITO (Indium Tin Oxide) heater glasses taped on four Plexiglas walls independently to provide the same constant heat flux boundary conditions. The size of the heated channel is 600 mm*80 mm*80 mm. TLCs was used for measuring the two-dimensional detail distribution of the temperature on the leading surface and trailing surface of the channel. The pixel-level calibration method was used for reducing the error of the TLCs. In the experiments, the Reynolds number, based on the channel hydraulic diameter (D) of 80 mm and the bulk mean velocity, is 20000, and the rotation number are 0, 0.068, 0.135, 0.205, 0.273, respectively. The obtained result shows that rotation has an important different effects on the heat transfer of leading and trailing side. On the trailing side, the heat transfer increases with the rotation number monotonically along the stream wise (X direction), and rotation enhances the local Nu/Nus up to 20%. On the leading side, rotation weakens the Nu/Nus around 25% with the rotation number of 0.273. However, on the leading side, with the increase of rotation number, the Nu/Nus is not decreasing monotonically along the stream wise, there is a slight enhancement (turning point) along the stream wise with different rotation numbers. The position of turning point on the leading side is different with various rotation numbers. With higher rotation number, the turning point moves closer to the inlet of the channel. This phenomenon is an important reference to investigate the flow field in our future work with PIV. More details of two-dimensional distribution Nu on the leading and trailing side will be shown in this work.

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