Interferometer Study of the Effects of Mass Addition by Transpiration on Heat Transfer from a Vertical Plate in Free Convection

摘要

A study was made of the effects of transpiration mass addition on heat transfer from a flat plate in steady state free convection. The investigation was conducted using a vertical plate heated to temperatures up to 150F. The effects of low blowing rates on heat transfer were determined by investigating the effects on the surface heat transfer coefficient, the boundary layer temperature profile, and the Nusselt, Prandtl and Grashof number relationship. An interferometer was used to visually observe the boundary layer and to provide a direct means of calculating the heat transfer coefficients and temperature profiles. Blowing was found to greatly reduce the surface heat transfer coefficient and change the boundary layer temperature profile by reducing the surface temperature gradient. This study also indicates that it may be feasible to apply the equation relating Nusselt, Prandtl and Grashof numbers for free convection to include mass addition by transpiration. (Author)