An experimental investigation has been carried out to examine heat-transfer characteristics of an axisymmetric, underexpanded, sonic jet impinging on a flat plate. The ratio of nozzle-exit pressure to the ambient pressure, that is, underexpansion ratio ranges from 1.5 to 3.5, and the distance from the nozzle exit to the plate is adjusted from 0.5 to 20.0 nozzle-exit diameters. Detailed measurements of the recovery factor and the surface pressure on the flat plate have been achieved. The results showed that the recovery factor obtained in the present study have distributions that are different from those for low-velocity jets. It has been found that the recovery factor at the stagnation point varies from 0.35 up to over 1.25 for the highest underexpansion ratio of Pe/Pa = 3.5 within the present experimental range.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics