Pressure-sensitive paint measurements for microscale supersonic flow with wedge models

The pressure distribution around wedge models inside a submillimeter supersonic wind tunnel was experimentally investigated using pressure-sensitive paint (PSP) at a flow speed of Mach 1.6. The throat of the submillimeter supersonic wind tunnel was 500 mu m. The two wedge models were isosceles triangles with a width of 50 mu m and vertex angles of 20 degrees and 30 degrees, respectively. The pressure profiles and pressure distributions along the centerline inside the submillimeter supersonic wind tunnel with the wedge models agreed with the results of numerical simulation performed using ANSYS Fluent. The pressure distributions around the wedge models were examined, and a strong pressure rise at the front end of the wedge models was observed. A low-pressure region in the wake region downstream of the wedge models was identified. However, these results differed from the simulation data for the middle layer of the wind tunnel, which revealed bow shock and a shock wave interaction. This difference occurred because the PSP coating was located at the bottom of the wind tunnel, which was embedded inside a viscous layer. The pressure data measured with PSP were smeared, and it was consistent with the simulation data for the bottom layer. The PSP results reveal the overall pressure variation around the wedge models, and they will be useful for future designs of micro propulsion systems with supersonic nozzles. (c) 2022 Elsevier Masson SAS. All rights reserved.

Automated summary

The pressure distribution around wedge models inside a submillimeter supersonic wind tunnel was experimentally investigated using pressure-sensitive paint (PSP) and compared with numerical simulation. The study found a significant pressure rise at the front end of the wedge models and a low-pressure region downstream. However, there were differences between the experimental and simulation data for the middle layer, likely due to the spreading of pressure data caused by the location of the PSP coating at the bottom layer.