Heat Transfer of Laminar Free Convection of Monatomic and Diatomic Gases, Air, and Water Vapor

Abstract

AbstractThe new similarity analysis method is used to replace the traditional Falkner-Skan type transformation for creating similarity governing models of laminar free convection. With this method, the velocity components are directly transformed into the corresponding dimensionless velocity components. Then, it is more convenient to equivalently transform the governing partial differential equations into the related ordinary differential ones, without inducing stream function and the intermediate function variable required by the traditional Falkner-Skan type transformation. Furthermore, with this method, it is more convenient for treatment of variable physical properties. The temperature parameter method is used for treatment of variable physical properties of gases. With this method the physical property factors coupled with the governing ordinary differential equations are transformed to the functions of the Prandtl number, temperature parameters, and the boundary temperature ratio for simultaneous solution. There are obvious effects of variable physical properties on velocity and temperature fields, as well as heat transfer of free convection of gas. Based on the heat transfer analysis and related rigorous numerical results, the prediction equations of gas free convection heat transfer is created. Since the Prandtl number and temperature parameters of gases are based on the experimental data, these prediction equations of gas free convection heat transfer are reliable and then have practical application value.KeywordsHeat TransferNusselt NumberFree ConvectionAverage Nusselt NumberAverage Heat Transfer CoefficientThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.