Pressure-sensitive paint measurement of pressure distribution in a supersonic micronozzle

Micronozzles have recently commanded considerable attention because of their potential applications, such as in flow control of microspacecraft It is difficult to understand fundamental physical phenomena in microscale flow due to the lack of suitable quantitative measurement tools (pressure and temperature sensors, etc.). Pressure-sensitive paint is one of the most promising options for global distribution measurement in microscale flow. In this paper, pressure distribution in a supersonic micronozzle with a nozzle throat of 250 μm was investigated using pressuresensitive paint, and the experimental results were compared with numerical simulation by Reynolds-averaged Navier-Stokes equations in three-dimensional space. The pressure-sensitive paint measurement technique demonstrated its validity for quantitative measurement of pressure distribution in microscale flow and revealed that the performance of the present micronozzle is critically affected by the boundary layer along the side wall.