Design method of a two-phase annular nozzle in cryogenic liquid expander

Abstract

The two-phase annular nozzle is a critical component of liquid expanders. It matches the outlet of the first stage and the inlet of the second stage. A design method of two-phase annular nozzle involving a two-step process is proposed. Nonequilibrium effects are introduced by the area factor during the second process. The flashing in two-phase annular nozzle is simulated through the cavitation method and validated by the experimental results of Brookhaven National Laboratory’s nozzle and Hord’s hydrofoil. A forward flashing two-phase annular nozzle and a backward flashing two-phase nozzle are designed with different centerline angle distributions where they show a good agreement with the design. Forward flashing two-phase annular nozzle exhibits high curvature and nonuniformity. Backward flashing two-phase nozzle exhibits lower nonuniformity and a slightly higher boundary layer ratio, which shows a better performance in terms of the nonequilibrium effects.