Novel method for quantitative and real-time measurements on engine combustion at varying pressure based on the wavelength modulation spectroscopy

The wavelength modulation spectroscopy (WMS) technique has been demonstrated as a powerful and indispensable tool for quantitative and real-time measurements on the combustion process of various industrial devices. However, the varying pressure occurred in the aero-engine combustor significantly affects the accuracy and efficiency of the WMS technique. To address this issue, this work reports a novel method named WMS pressure correction model, which can enable fast signal processing in the measurements at varying pressure. The method was first validated in a heated optical cell, and then applied to the pressure and temperature measurements in an aero-engine combustor. The results show that the new method can efficiently and accurately measure the pressure and temperature at the varying pressure conditions.