Study Of Kerosene Fueled Dual-mode Ramjet Combustor Operation Process

The flame propagation, flame holding, stable combustion of kerosene in supersonic flow and dynamic working process of combustor were studied in detail by means of theoretical analysis, experimental investigation and numerical simulation. In this way, the configuration of dual-mode ramjet combustor was improved, a multi-cavity type emerged as the times require. The combustion performance and mode transition of this type of ramjet were conducted by both direct-connect and free-jet hot tests, many significant results were acquired.The process of flame propagation and holding were investigated experimentally by different ways of ignition. It is found that flame can be accelerated and spread upstream in the phase of ignition of certain cases, and the supersonic combustion flow field was made up of the resident flame in subsonic recirculating zone and diffusive flame in supersonic main flow.By comparing different 1-d models which were adopted for analyzing supersonic flow field, the limitations of these models turned up. A new 1-d model fitted for strong precombustion shockwave was put forward, which was validated by the direct-connect hot tests. Moreover, through analyzing the adiabatic no-shock pseudo-shock model for dual-mode combustor, different results derived from this model and 1-d models were given, the essence of calculating by using 1-d model with different area distribution was pointed out. Finally, the supersonic flow field was simulated with a modified non-adiabatic no-shock pseudo-shock model, the veracity of 1-d models by using different parameter was considered.It is found that multi-cavity type of combustor could improve both combustion efficiency and engine performance while investigating the mechanism of the interaction of cavities. The combustion performance of this type of combustor was tested on the direct-connect test-bed under the condition simulated Ma4, 5 and 6. These are of use to enhance the performance of dual-mode ramjet combustor.The combustion mode transition under various simulating conditions was carried out basing on the direct-connect test-bed, the contrast between pre-transition and after-transition engine performance was given.Finally, several free-jet tests were conducted under the condition of Ma4, 5 and 6 with a full size dual-mode ramjet engine. The flame holding and combustion mode transition were achieved under all incoming flow conditions. Positive thrust of this dual-mode ramjet engine was obtained.