Ion Current Based Pressure Sensor For Pulse Detonation Engines

During the research for pulse detonation engine (PDE), the pressure of detonation combustor is the key physical parameter for the succeeding of the detonation of the PDE. Its transient pressure not only can decide the ignition timing and ignition delay timing but also can affect the work frequency and efficiency of PDE. Since the work environment of the PDE is quite severe, the traditional piezoelectric pressure sensor is not applicable any more. As a result, a substitute sensor for pressure measuring is urgently needed.The ion current based on pressure sensor for PDE is studied in this paper. Two kinds of ion probes are designed and a serials single circle detonation experiments are carried out. The ion current and pressure during detonation are analyzed. The change of ion current is analyzed from ion probe length, bias voltage, chemic ratio and probe position. An ion based pressure sensor with single-pole and short probe is designed. The waveform of the sensor's current signals is similar with that of the pressure sensor. The sensor can also be used for measuring the detonation velocity and DDT (Deflagration to Detonation Transition) distance in simple circle detonation experiment.Through the analysis of experiment data, the linear relation model is established with the fitting method, which ensures the correctness of the theory deducing. A reliable method for measuring PDE pressure is proposed, that is to measure the ion current signal to ensure pressure. The sensor provides foundation for the controller design of PDE.