Simulation of a gaseous jet impinging on a convex heated surface – effect of inlet condition

Abstract

Flow and heat transfer due to a Nitrogen jet at ambient temperature impinging on an isothermally heated convex surface are numerically investigated and compared to experimental measurements obtained from a similar configuration. The temperature difference between the jet and the surface reaches up to 580 K and the nozzle-to-surface distance is equal to the nozzle diameter. On account of the small nozzle-to-surface distance and nozzle length, flow and heat transfer over the impinging surface are highly sensitive to the nozzle inlet conditions; therefore, in this study various inlet conditions are examined and compared. Due to high temperature variation, changes of density are accounted for using a compressible solver instead of constant property approach, widely used in the literature. For the same reason, temperature dependence of fluid properties is included in the solution. The agreement between the solution and experiments is reasonable, and mean velocity profile is found to have significant influence on surface heat transfer (up to 25% difference in stagnation point Nusselt number among different profiles).