1998 Fiscal Year Final Research Report Summary
Evaluation of Shock Behavior on Aerodynamic Instability of Transonic Cascade
| Project/Area Number |
08650218
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Tokyo Metropolitan Institute of Technology |
|---|
Principal Investigator |
SHIRATORI Toshimasa Faculty of Engineering, Tokyo Metropolitan Institute of Technology, Ass.Professor, 工学部, 助教授 (10107162)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SAKURAI Chuichi Faculty of Engineering, Tokyo Metropolitan Institute of Technology, Research Ass, 工学部, 助手 (50099339)
|
|---|
| Project Period (FY) |
1996 – 1998
|
| Keywords | Transonic Cascade / Shock Wave / Aerodynamic Instability / Compressible Flow |
|---|
| Research Abstract |
A series of experimental and computational studies has been carried out to evaluate effects of passage shock wave movements on 2-D transonic cascade flows aiming for clarification of aerodynamically unstable phenomena in transonic compressors.
In experimental studies, first, a system to measure positions of the shock wave fluctuating with high frequency was developed. The system consists of a schlieren optical system, a line scan camera and a data acquisition / processing computer. Next, experiments have been carried out to investigate the behavior of passage shock waves with the shock induced boundary layer separation in 2-D transonic cascade flows for unstaggered / staggered (30 degrees) cases. The time dependent streamwise shock positions and oscillation frequencies were measured by the above measuring system. The results show that the self-excited shock wave oscillations occur in a range of back pressures in the unstaggered and staggered cases. The fundamental frequencies of the shock oscillation are around 400 - 900 Hz in the tested conditions. A relation between the frequency and the mean shock position shows that the fundamental model of the shock oscillation mechanism can be supported in the unstaggered case, however an improved model is required in the staggered case.
In computational studies, calculations based on the Euler / Navier-Stokes equations have been carried out on a pitch oscillating 2-D transonic cascade. The shock behavior and the aerodynamic works were obtained at the various blade oscillation frequencies. The comparisons between the Euler and N-S solutions show that the shock structure, the differences of the bow shock behavior between the two solutions are relatively small, however, the behavior of the passage shock in the N- S calculations differs greatly from that of the Euler calculations. The difference leads to a significant variation in the prediction of the resultant aerodynamic stability or instability in torsional mode.
|
Research Products
(12 results)
