Improvements to Unsteady Pressure-Sensitive Paint Formulations

Improvements to unsteady pressure-sensitive paint (uPSP) formulations have been realized by judicious selection of titanium dioxide (TiO₂) particles and dispersant. Traditionally, uPSP formulations based on polymer/ceramic coating have been used in many wind tunnel test campaigns but suffer from photodegradation and changes in pressure sensitivity during the testing window. As such, this paper details the investigation of employing different grades of TiO₂ particles and dispersants to achieve desirable characteristics such as coating properties, pressure sensitivity, frequency response and overall degradation. Employing hydrophobic TiO₂ particles along with a high-molecular-weight acrylic co-polymer generated uPSP coatings with many desirable features, including smoothness, thickness, and pressure sensitivity. In addition, the pressure sensitivity of the coatings exhibited linear behavior, having very little dependence on temperature. Finally, the frequency response was characterized qualitatively, and all uPSP formulations tested exhibited response to pressure fluctuations up to 12 kHz.