Pressure-sensitive paint integrated with digital image correlation for instantaneous measurement on rotating blades

In wind tunnel tests, there is a strong demand for simultaneous pressure and deformation measurement techniques, especially for objects with complex aerodynamic shapes or with significant deformation and displacement. A novel speckle pattern pressure-sensitive paint (PSP) system was proposed in this work. The single-shot lifetime method and stereo digital image correlation (DIC) technique were integrated into this system. A random speckle pattern was printed on the PSP surface with a photosensitive seal. The luminescent images with this additional pattern were used to generate point cloud data through cross-correlation analysis and triangulation. The speckle pattern was also helpful to realize pixel to pixel image registration for pressure field reconstruction. This system was successfully applied to simultaneously measure the instantaneous pressure and deformation field of a high-speed rotating blade. The pressure measurement results from the speckle pattern PSP were highly consistent with those from the regular PSP. The average standard deviation (STD) was around 200 Pa. The accuracy of the deformation field measurement was evaluated by comparing the measured point cloud data with the CAD model, showing an average deviation of 0.13 mm.