Fabrication and characterization of mesoporous pressure-sensitive luminescent particles for in-flow measurement of pressure and velocity

A class of micron pressure sensitive fluorescent particles is developed. Porous hollow SiO₂ particles and pressure-sensitive fluorescent materials (PtTFPP & Ru(dpp)) are used in these particles. Multifunctional tracer particles are prepared through attaching fluorescent materials to particles by the dip-dye method. Then a new simultaneous pressure and velocity measurement can be developed by combined Particle Image Velocimetry (PIV) technology and Pressure Sensitive Paint (PSP) technology. The signal intensity, the pressure sensitivity, and the pressure response time are measured by the static and dynamic PSP calibration system. Effects of different particle sizes and different materials on properties of pressure sensitive fluorescent particles are studied. The calibration result reveals that the pressure sensitive fluorescent particles have good pressure sensitivity, and the 40~70μs pressure response time is suitable for measuring the transient pressure in the flow field. The tracking ability is analyzed. The 2μm particles have 7.5μs relaxation time which show a qualified tracking ability.