Research On Flame Detection Of Scramjet Combustor

In order to meet the demand of the future space transportation technology development and military motivation, countries all over the world are committed to the development of hypersonic vehicles. Among all the critical technologies associated with hypersonic vehicles, scramjet technology is one of them, which includes optimization design, materials, inlet, fuel properties, time-varying process, combustion process and kinetic energy recovering. As the airflow velocity in the scramjet combustor is more than 1000 m/s, the time that fuel stayed in the combustor is in a milli-second level, which result in igniting and maintaining flame hardly in the combustor. Local temperatures, pressure, make-up of fuel and supply of energy in the flow field have a great effect on the combustion and would even cause a flameout of engine, which limits the aircraft's mobility and tactical performance.The basis of engine working well at high mach numbers is as follows: (1), an effective mixing of air flow and fuel injection; (2), igniting and maintaining the flame. Therefore, it is very necessary to design an effective detector to detect the flame in the scramjet combustor. The work of this study is as follows:Flame detector hardware of scramjet combustor is constructed based on the natures of the flame and the basic measurement method of the optoelectronic signals, including photoelectric circuit design, analog signal circuit design, the selecting of microprocessors and the external expansion circuit design.Based on the hardware platform system of flame detector for scramjet combustor, flame detection of scramjet has been realized, using Fast Fourier Transform and fuzzy identification theory. Flameout of combustor has also been realized using wavelet theory.Based on the hardware/software platform system of flame detector for scramjet combustor, the performance of the flame detector for scramjet combustor has been validated by experimental study. Compare and analyse design requirements with the experiment results.