IMPINGEMENT OF AXISYMMETRIC UNDER-EXPANDED SONIC JETS ON A FLAT PLATE

摘要

An experimental investigation has been carried out to examine heat transfer characteristics of an axisymmetric, under-expanded, and sonic jet impinging on a flat plate. Distributions of recovery factor and the surface pressure on the flat plate have been obtained in detail. The ratio of nozzle exit pressure to the ambient pressure, i.e., under-expansion ratio ranges from 1.5 to 3.5 and the nozzle-to-plate distance is tested from 0.5 to 20.0 nozzle exit diameters. It has been found that the recovery factor varies from 0.35 up to over 1.25 depending on both parameters of interest within the present experimental range.