Acoustic oscillatory pressure control for ramjet
US4760695A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 23, 1987 |
| Grant date | Aug 2, 1988 |
| Priority date | — |
| Expiry date | Jun 23, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02K9/26
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The periodic shedding of vortices produced in a highly sheared gas flow, such as that encountered at the grain transition boundary in a solid propellant rocket motor or at the combustor inlet to a ramjet engine, is a significant source of acoustic instability which may result in unstarting of the ramjet engine or excessive vibration of the rocket motor. By restricting the transition boundary or combustor inlet at the sudden expansion dump plane (5), such as by locating an orifice plate (13) at the dump plane, the gas flow is separated upstream and produces a vena contracta downstream of the orifice, inhibiting the feedback of acoustic pressure to the point of flow separation and preventing the formation of organized oscillations. Incorporation of such a simple thin plate orifice at the dump plane reduces the periodic acoustic oscillations and thereby controls the detrimental oscillatory pressure fluctuations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.