Effects of grid turbulence on nonequilibrium choked nozzle flow

Experiments were conducted to investigate the role played by grid-produced turbulence on the nonequilibrium choking process in short nozzles with subcooled upstream conditions. Grids were placed upstream of the nozzle to alter the intensity and scale of turbulence. These changes were reflected in the degree of thermodynamic nonequilibrium in the nozzle and in the critical mass flux. It was found that the data were ordered logically by the turbulent integral-length scale. Subsequently, a nonequilibrium vapor generation model based on a description of the turbulent transport of thermal energy was developed. The vapor generation model was combined with conservation equations to define the critical flow condition. This model was then examined with respect to data available in the open literature. 9 refs.