Convective heat transfer in the near-wall turbulent gas stratum

3rd International Scientific and Technical Conference “Energy Systems”

Kuznetsov, V.A.^1 ; Trubaev, P.A.^1

Department of Energy Engineering of Heat Technologie, Belgorod State Technological University of V.G. Shuchov, Belgorod

308012, Russia^1

关键词: Computational costs;    Convective heat transfer;    Dimensionless velocity;    Heat transfer simulation;    Numerical algorithms;    Semi-empirical formulas;    Semiempirical hypothesis;    Turbulent gas flows;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/552/1/012005/pdf
DOI  :  10.1088/1757-899X/552/1/012005

来源: IOP

【 摘 要 】

In order to diminish the computational cost of heat transfer simulations, some wall functions had been often introduced in numerical algorithms. More universal and robust dimensionless velocity functions that can be employed both in buffer and equilibrium parts of the near-wall turbulent gas stratum are offered here for consideration. They have been obtained on the basis of Prandtl's semiempirical hypothesis of turbulence. A mode, how to determine the one-sided derivatives of the gas velocity and temperature at the wall surface on a coarse grid, has been substantiated. That allows applying the boundary conditions of Neumann and Robin type for differential equations of the convective heat transfer to the confining walls from the turbulent gas flow. A semiempirical formula for the eddy viscosity in the wall proximity has been deduced, and a valid boundary value has been determined also for the rate of turbulence-energy dissipation. It is demonstrated that the simulation results coincide sufficiently with experimental data.