Investigation of entropy generation over a backward facing step under bleeding conditions

The current work investigates entropy generation around a backward facing step subjected to bleeding by using suction/blowing. The suction/blowing is imposed on the bottom wall of the step. Finite volume method with second order accuracy is used in the solution of the governing equations. The variation of local and overall entropy generation number is calculated. The distribution of entropy generation number on the top wall and the bottom walls of the step is estimated. Moreover, the average Bejan number is calculated over the entire domain. High values of Bejan number are identified on the top and the bottom walls. The effect of bleed coefficient on the entropy generation number and Bejan number are presented.

[1]  Chin‐Hsiang Cheng,et al.  Entropy generation and heat transfers via laminar forced-convection channel flows over transverse fins in entrance regions , 1989 .

[2]  F. White.  Viscous Fluid Flow , 1974 .

[3]  M. Abu-Qudais,et al.  Entropy Generation due to Laminar Natural Convection From a Horizontal Isothermal Cylinder , 1998 .

[4]  R. Henderson,et al.  Three-dimensional instability in flow over a backward-facing step , 2000, Journal of Fluid Mechanics.

[5]  A. Bejan.  A Study of Entropy Generation in Fundamental Convective Heat Transfer , 1979 .

[6]  Eiyad Abu-Nada,et al.  Numerical Prediction of Entropy Generation in Separated Flows , 2005, Entropy.

[7]  Eiyad Abu-Nada,et al.  Entropy generation due to heat and fluid flow in backward facing step flow with various expansion ratios , 2006 .

[8]  Adrian Bejan,et al.  The thermodynamic design of heat and mass transfer processes and devices , 1987 .

[9]  George Em Karniadakis,et al.  Onset of three-dimensionality, equilibria, and early transition in flow over a backward-facing step , 1991, Journal of Fluid Mechanics.

[10]  Effect of stepheight on the separated flow past a backward facing step , 1989 .

[11]  Chia-Jung Hsu.  Numerical Heat Transfer and Fluid Flow , 1981 .

[12]  K Abu-Hijleh,et al.  Numerical prediction of entropy generation due to natural convection from a horizontal cylinder , 1999 .

[13]  P. Moin,et al.  Application of a Fractional-Step Method to Incompressible Navier-Stokes Equations , 1984 .

[14]  Lambros Kaiktsis,et al.  Sidewall effects in flow over a backward-facing step: Experiments and numerical simulations , 2002 .

[15]  Weeratunge Malalasekera,et al.  An introduction to computational fluid dynamics - the finite volume method , 2007 .

[16]  G. Vradis,et al.  Laminar coupled flow downstream of an asymmetric sudden expansion , 1992 .

[17]  B. Armaly,et al.  Experimental and theoretical investigation of backward-facing step flow , 1983, Journal of Fluid Mechanics.

[18]  D. Gartling.  A test problem for outflow boundary conditions—flow over a backward-facing step , 1990 .

[19]  Bilal Akash,et al.  Heat Transfer and Fluid Flow Characteristics of Separated Flows Encountered in a Backward-Facing Step Under the Effect of Suction and Blowing , 2007 .