2004 Fiscal Year Final Research Report Summary
Development of Numerical Simulation Method for Unsteady Cavitating Flow
| Project/Area Number |
14550138
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
IKOHAGI Toshiaki Tohoku University, Institute of Fluid Science, Professor, 流体科学研究所, 教授 (90091652)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IGA Yuka Tohoku University, Institute of Fluid Science, Research Associate, 流体科学研究所, 助手 (50375119)
|
|---|
| Project Period (FY) |
2002 – 2004
|
| Keywords | Cavitation / Phase Change / Numerical Simulation / Cascade Flow / Turbopump |
|---|
| Research Abstract |
In this study, on the occasion of design and development of fluid machineries such as turbopump of liquid rocket engine, a numerical method that can clarify unsteady characteristics of high-speed cavitating flowfields in detail was developed to come into practical use. The numerical method can treat mixture condition for liquid and gas phases and for regions of low Mach number and supersonic flows in cavitating flow all at once. Through numerical analyses about several kinds of flowfields with cavitation, availability of the method is verified.
3D unsteady cavitating flow around single hydrofoil was analyzed numerically by using the present method. It was found that shedding cloud cavity has 3D large-scale structure of U-shaped vortex by the influence of a boundary layer developed on the channel sidewalls.
In analyses of flat-plate cascade flow, two kinds of mechanism in break-off phenomenon of sheet cavity were predicted depending on cascade arrangement. In analyses of flat-plate cascade with three-blade cyclic condition, it was showed that three kinds of typical cavitation instabilities, such as forward rotating cavitation, rotating-stall cavitation and cavitation surge, which usually occur in turbopump were represented numerically. The present method can predict above three unstable phenomena without additional modeling corresponding to the respective phenomena.
Through analyses of tandem three-blade cascade flow, through an investigation of slit effect between front and rear blades in tandem cascade on cavitating flowfield, it was showed clearly that occurrence of cavitation instabilities can be reduced by influence of a slit flow that increases irregularity of cavitation periodicity.
In analyses of cavitating water jet injected into air, it was clarified that impact pressure by collapse of cavity cloud in nozzle induces large-scale deformation of water jet interface.
|
