Investigation of mechanical chocking aided ignition and flame stability in RBCC ramjet modal

Paper number

IAC-09.C4.8.4

Author

Mr. xiaowei liu, China

Coauthor

Prof. Guoqiang He, Northwestern Polytechnical University, China

Coauthor

Prof. Pei-Jing Liu, Northwestern Polytechnical University, China

Coauthor

Mr. Man Zhang, China

Coauthor

Mr. xiaowei liu, China

Year

2009

Abstract

In order to gain the best performance during ramjet and scramjet modal，the extended combustor, which has an essential distinction to the normal ramjet combustor, is more suitable for RBCC engine. There should be a thermal throat, like the mechanical nozzle after the normal ramjet combustor, at the back of the extended combustor, in order to attain stable combustion and enough thrust during ramjet modal. The formation of the thermal throat needs great heat release in the combustor, but this condition could not be achieved at the ignition stage owing to the poor heat release, so the flame stability is impossible, and the ignition will fail. However, the mechanical chocking aided ignition will be feasible, borrowing ideas from the normal ramjet combustion.
In the paper, the experimental and numerical investigations of mechanical chocking aided ignition and flame stability in RBCC ramjet modal were carried out on the direct connection experimental bench at the National key laboratory of combustion, flow and thermo-structure of NPU. The experimental engine is consisted of attachment nozzle, simulating the air flow from inlet, block isolator, extended combustor and exit area adjustable nozzle. There are position adjustable reentrants in the combustor. Near the reentrants, there are injection holes and injection rods with different length. The guide flame is ethane flame. The flues are kerosene oil and alcohol. 
A low speed and high temperature region, favorable for ignition, was formed by regulating the chock ratio at the engine exit. Then a reliable ignition was implemented with the use of the reentrant flame stabilizer and the ethane guide flame. The investigation indicated that outlet chock ratio, reentrant position, fuel species, fuel injection mode and equivalent proportion would have an effect on the ignition and the flame stability. The regularities of the influences of these factors were investigated too, and the mechanics was analyzed carefully. The investigation here lays a fine foundation for the implementation of a stable high efficient combustion based the thermal throat in RBCC ramjet modal.

Abstract document

IAC-09.C4.8.4.pdf

Manuscript document

IAC-09.C4.8.4.pdf (🔒 authorized access only).

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