Study on the influence of pneumatic probe on the wake flow field of transonic turbine cascade

The pneumatic probe is widely used for contact measurements in turbomachinery flow field research. However, it inevitably interferes with the original flow field, leading to additional errors, particularly in wake flow fields or transonic regions with significant pressure gradients. This study employed Reynolds-Averaged Navier-Stokes delete and high-fidelity numerical simulation to investigate the impact of an inserted pneumatic probe on the wake flow field of a transonic turbine blade and compared it to the baseline flow field. Results indicate that the probe causes the shock waves premature occurrence in the high subsonic wake region near the turbine blade trailing edge. These shock waves affect vortex shedding by thickening the boundary layer near the trailing edge and changing the shedding pattern from high-frequency-low-energy to low-frequency-high-energy. In addition, the extra flow loss is incurred, and the blade’s heat transfer characteristic is changed. This research provides a reference for testing experiments in complex transonic flow fields, guiding experimental researchers to minimize instrument interference with the original flow field.