Effects of Gas Radiation on the Performance of a Hot Impinging Round Jet

The heat transfer characteristics of a hot impinging jet with gas radiation effects are studied. Two-dimensional cylindrical, steady, turbulent flow is simulated using the k-ε model. The discrete-ordinates method is used to solve the equation of radiative transfer for gas radiation. Numerical results are obtained for Reynolds numbers from 2.38x10^4 to 1.0x10^5. Solutions are presented for the temperature distribution and heat flux along the impingement wall. The effects of important parameters, such as optical properties (absorption coefficient), the nozzle-to-plate distance, the Reynolds number, and the surface emissivity of the wall are examined. Results show that the radiative heat flux at the stagnation point is reduced by 86 percent approximately when the absorption coefficient of the gas is increased from 0.005 cm^(-1) to 0.2 cm^(-1). As the nozzle-to-plate distance is increased from 2 to 8 nozzle diameters, the radiative heat flux is reduced by 94 percent at the stagnation point. When the Reynolds number is decreased from 1.0x10^5 to 2.38x10^4, the total heat flux is decreased by 25 percent. The radiative and total heat fluxes decrease as the surface emissivity is decreased.

並列關鍵字

Hot impinging jet ； Gas radiation ； Discrete-ordinates method

國際替代計量

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