Effect of Geometric Parameters on the Performance of Second Throat Annular Steam Ejectors
Final rept. 28 Feb-30 Sep 1990
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Pagination or Media Count:
Steam ejectors are simple pumps that, among many possible applications, are used in altitude simulation rocket motor testing. Of the two main types of ejectors, annular and centerbody, the latter has been the subject of most previous research. Less is known about the operation of annular ejectors. For example, ejector diffusers that contain a contraction known as a second throat have been studied widely for centerbody configurations however, very little work has been conducted to determine the effects of specific design variables. The design variables investigated were second throat area ratio has a strong impact on system operation, as expected. The second throat axial position appears to have a mild impact on the overall pressure recovery of the system over most of the range investigated, but with a strong effect when the second throat ramp is moved forward to the steam nozzle outlet. At the point, there is a large degradation in cell pressure. Ramp angle over the range investigated does not have a significant effect on cell pressure. A computational study was also conducted to evaluate the suitability of a single-phase Navier-Stokes computational fluid dynamics CFD code for prediction of stream ejector flow fields. The results of the study concluded that the state of the art circa 1989 was insufficient for the successful prediction of ejector performance. The inability to model the condensation effects is indicated as a major cause of a deficiency.
- Fluid Mechanics