減圧沸騰を伴う先細末広ノズルの性能特性 : 第2報,ノズル性能の改善

概要

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The purpose of this study is to improve the performance characteristics of a convergent-divergent nozzle for flashing expansion of initially subcooled hot water. Slip between vapor and liquid in the divergent passage and pressure undershoot (that is, thermal nonequilibrium) at the nozzle throat causes the nozzle efficiency to decrease. Initially subcooled hot water at an inlet pressure of 0.47 MPa and inlet temperatures of 409.8 to 421.8 K (inlet subcoolings of 0.9 to 12.9 K) were used in the range of nozzle back pressures of 5 to 101.3 kPa. The results showed that: (1) pressure undershoot is decreased and the thrust coefficient is increased by 10%; (2) a thrust coefficient is independent of the inlet subcooling and exit-stream expansion ratio; (3) a method for determining the exit-stream expansion ratio is proposed; (4) the critical flow rate is lower than that for an ordinary convergent-divergent nozzle.
1989-09-25