Special features of heat transfer under conditions of heat protection of high-temperature firing walls of components of modern power-generating units by way of tangential injection

Abstract

In order to more precisely define the characteristics of heat transfer under conditions of protection of firing wall by means of tangential injection in the case of its high temperature (in particular, higher-thanadiabatic temperature) and to assess the effect of degree of turbulence of the incoming gas flow on heat transfer, a numerical investigation is performed under conditions of parameters typical of combustors of gas-turbine plants (GTP) with high parameters of the working medium. In so doing, the heat flux distribution, the profiles of turbulence intensity, the distribution of turbulent viscosity in the injection zone region under study, and other characteristics are determined. The low-Reynolds k-e model with wall functions and a new model of turbulent viscosity without wall functions are employed. It is found that a maximum of turbulent viscosity takes place behind the exit section of the injection slit with a shift to the main flow under conditions of tangential injection on an isothermal surface with a temperature much in excess of injection temperature (in a more general case, Tw > Tad). This causes impairment of heat protection by injection, i.e., an increase in heat fluxes in the computational domain compared to heat fluxes calculated using integral methods.