| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 92 ===
This study presents the numerical study of transient conjugate heat transfer in a high turbulence air jet impinging over a flat circular disk. The numerical simulation of transient, two dimensional cylindrical coordinate, turbulent flow and heat transfer is adopted to test the accuracy of the theoretical model. The turbulent-governing equation are resolved by Control-Volume based finite-different method with power-low scheme, and the well-known turbulence model to describe the turbulent structure. The SIMPLE algorithm is adopted to solve the pressure-velocity coupling.
The parameters studied include time (t=0.1s~200s), turbulent flow Reynolds number (Re=16100、23700、29600), heated temperature in circular disk( =373K) or heat flux( =63 、126 、189 ), and orifice to heat-source spacing (H/D=4、6、10), and the working medium is air.The numerical results of transient impinging process indicate that the jet Reynolds numbers has a significant effect on the hydrodynamics and heat transfers，particularly in the stagnation region of an impinging jet under the consideration of jet Reynolds number(Re=16100、23700、29600)and impinging height (H/D=4、6、10). The maximum temperature at the interface and the maximum temperature inside the disk decrease as Reynolds number increase, where as the maximum to minimum temperature at the interface increases with Reynolds numbers. The numerical results have been compared with experimental data of Siba et al. (2003) in the literature. The closed agreement supports the validity of the numerical study. Numerical prediction obtained from this study will provide physical insight into conjugate heat transfer effects and facilitates validation of numerical conjugate heat transfer models.
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