HEAT TRANSFER IN A 60°HALF-ANGLE OF CONVERGENCE NOZZLE WITH VARIOUS DEGREES OF ROUGHNESS

摘要

An experimental heat-transfer study has been conducted in a converging-diverging nozzle having various values of wall roughness. The working fluid was air, which was heated to a stagnation temperature of 970° R (538 K). The stagnation pressure was varied from 30 to 300 psia (20.7 to 206.9 N/cm2). The nozzle was roughened by a sandblasting technique to three levels of roughness: 120, 175, and 325 rms (305x10, 445x10, and 826x10 cm rms). Both a cooled and an adiabatic inlet, each having smooth walls, were used to determine the effects of the thermal history of the fluid on the nozzle heat transfer.