Development of Pressure Sensitive MicroBeads for the Simultaneous Measurements of Pressure and Velocity

We have recently synthesized pressure sensitive microbeads (PSBeads) consisting of a platinum octaethylporphryin luminophore in a polystyrene matrix, and a novel osmium-based luminophore in a silicon dioxide matrix. Since these PSBeads are to provide simultaneous measurements of pressure and velocity in turbulent and/or high speed flows, their response times must be sufficiently fast. A shock tube was constructed to provide a test facility where the response time of the microspheres could be reliably measured. Initial studies showed response times are on the order of 20 $\mu $s -- 2 ms when exposed to shock strengths of $\sim $1.07 $M$ ($\Delta P \quad \approx $ 10-12 kPa). We further use this facility to obtain preliminary simultaneous pressure and velocity measurements before and after a shock wave.