Local heat/mass transfer distributions on the bottom surface of a cavity exposed to an approaching turbulent boundary layer

Mass transfer measurements on a flat plate downstream of a belt moving in the same direction of the freestream study the effect of the upstream shear on the heat (mass) transfer for four belt-freestream velocity ratios. With an increase in this ratio, the “virtual origin” of the turbulent boundary layer “moves” downstream toward the trailing edge of the belt. This is verified from the variation of the Stanton number versus the Reynolds number plots. As the “inner” region of the boundary layer is removed for a belt speed of uw=10 m/s (freestream velocity uin≈15.4 m/s), a corresponding local minimum in the variation of the Stanton number is observed. Downstream of this minimum, the characteristics of the turbulent boundary layer are restored and the data fall back on the empirical variation of Stanton with Reynolds number.

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A transformation theory for the compressible turbulent boundary layer with mass transfer

10.2514/6.1969-161 ◽

1969 ◽

Cited By ~ 2

Author(s):

C. ECONOMOS

Keyword(s):

Boundary Layer ◽

Mass Transfer ◽

Turbulent Boundary Layer ◽

Transformation Theory

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Numerical Simulation of Heat Mass Transfer Effects on MHD Flow of Williamson Nanofluid by a Stretching Surface with Thermal Conductivity and Variable Thickness

Coatings ◽

10.3390/coatings11060684 ◽

2021 ◽

Vol 11 (6) ◽

pp. 684

Author(s):

Saeed Islam ◽

Haroon Ur Rasheed ◽

Kottakkaran Sooppy Nisar ◽

Nawal A. Alshehri ◽

Mohammed Zakarya

Keyword(s):

Thermal Conductivity ◽

Boundary Layer ◽

Mass Transfer ◽

Differential Equations ◽

Variable Thickness ◽

Heat Mass Transfer ◽

Mathematical Formulation ◽

Stretching Surface ◽

Nanofluid Flow ◽

The Impact

The current analysis deals with radiative aspects of magnetohydrodynamic boundary layer flow with heat mass transfer features on electrically conductive Williamson nanofluid by a stretching surface. The impact of variable thickness and thermal conductivity characteristics in view of melting heat flow are examined. The mathematical formulation of Williamson nanofluid flow is based on boundary layer theory pioneered by Prandtl. The boundary layer nanofluid flow idea yields a constitutive flow laws of partial differential equations (PDEs) are made dimensionless and then reduce to ordinary nonlinear differential equations (ODEs) versus transformation technique. A built-in numerical algorithm bvp4c in Mathematica software is employed for nonlinear systems computation. Considerable features of dimensionless parameters are reviewed via graphical description. A comparison with another homotopic approach (HAM) as a limiting case and an excellent agreement perceived.

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Effects of Bleed Flow on Heat/Mass Transfer in a Rotating Rib-Roughened Channel

Journal of Turbomachinery ◽

10.1115/1.2720495 ◽

2006 ◽

Vol 129 (3) ◽

pp. 636-642 ◽

Cited By ~ 8

Author(s):

Yun Heung Jeon ◽

Suk Hwan Park ◽

Kyung Min Kim ◽

Dong Hyun Lee ◽

Hyung Hee Cho

Keyword(s):

Mass Transfer ◽

Heat Mass Transfer ◽

Local Heat Transfer ◽

Local Heat ◽

Main Flow ◽

Hydraulic Diameter ◽

Transfer Coefficients ◽

Square Channel ◽

Rib Turbulators ◽

Sublimation Method

The present study investigates the effects of bleed flow on heat/mass transfer and pressure drop in a rotating channel with transverse rib turbulators. The hydraulic diameter (Dh) of the square channel is 40.0mm. 20 bleed holes are midway between the rib turburators on the leading surface and the hole diameter (d) is 4.5mm. The square rib turbulators are installed on both leading and trailing surfaces. The rib-to-rib pitch (p) is 10.0 times of the rib height (e) and the rib height-to-hydraulic diameter ratio (e∕Dh) is 0.055. The tests were conducted at various rotation numbers (0, 0.2, 0.4), while the Reynolds number and the rate of bleed flow to main flow were fixed at 10,000 and 10%, respectively. A naphthalene sublimation method was employed to determine the detailed local heat transfer coefficients using the heat/mass transfer analogy. The results suggest that for a rotating ribbed passage with the bleed flow of BR=0.1, the heat/mass transfer on the leading surface is dominantly affected by rib turbulators and the secondary flow induced by rotation rather than bleed flow. The heat/mass transfer on the trailing surface decreases due to the diminution of main flow. The results also show that the friction factor decreases with bleed flow.

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