Total Pressure Loss in Supersonic Nozzle Flows with Condensation (Numerical Analyses)

Abstract

The rapid expansion of moist air or steam in a supersonic nozzle gives rise to condensation, and the total pressure of the flow is reduced by this nonequilibrium phenomenon. In the present paper, a method is presented for calculating a loss in total pressure due to condensation generated by a rapid expansion of moist air in a supersonic circular nozzle. The loss in total pressure has been determined from the amount of increment in the entropy produced as the result of the irreversibility in the nonequilibrium condensation process. The calculated values of the total pressure loss are a little smaller than those of the experimental results, and they are about 2 to 5 percent in the present calculation. Based on the calculated results, the effects of degree of supersaturation of moist air and the shape of the nozzle on the total pressure loss have been clarified quantitatively.