Multimode Control of Axial Compressors via Stability-Based Switching Controllers

Abstract

Conclusions It would appear that the unrecoverable loss in thrust resulting from nonuniform velocity at the nozzle entrance is not likely to exceed about 1%, unless large variations in velocity are encountered. However, some reservations should be noted. For this example, the loss in thrust is about four times as great as the loss in nozzle efficiency. Also, the thrust in this example is quite high. In more marginal engines, a small loss in exit momentum could be much more significant. In addition, it is important to recall that it has been assumed here that the nonuniform inlet conditions are known and have been taken into account in the nozzle design. If the design is faulty, then larger losses are possible, and may be inevitable in a flight environment involving changes of angle of attack, altitude, and Mach number.