An accumulated imaging method with phase-locking for rotor pressure-sensitive paint measurements

The evolution of pressure-sensitive paint (PSP)-based surface pressure measurement technology for rotating machinery is significant for flow mechanism analysis and blade design. Considering the challenges of reducing motion blur and improving signal-to-noise ratio (SNR) in the application of PSP technology for the rotating machinery, an accumulated imaging method with phase-locking based on the periodic characteristics of the rotor flow field has been proposed in this study, which is capable of capturing the phase-averaging pressure on the rotor blade surface. The motion blur is reduced by pulse acquisition of PSP luminescent, and the SNR is improved by accumulating luminescent signals of the same phase multiple times, which can address the challenge. Single PSP luminescence acquisition time and accumulation number are the two most crucial parameters for measurement accuracy, and the constraints of the parameters are discussed in detail according to the principle of PSP. The PSP measurement system for rotating machinery based on the proposed method has been established, and the method is successfully applied to the rotating blade surface pressure measurement of a transonic axial fan. Besides, the proposed method can also be applied to the temperature measurement of the rotating blades based on temperature-sensitive paint. The results offer a technical foundation for the pressure measurement of rotating machinery.