Simultaneous velocity and pressure measurements using luminescent microspheres
Review of Scientific Instruments
Using the technique of modified rapid lifetime determination, pressure-sensitive microspheres, known as PrSBeads, were used to make quantitative oxygen measurements over two-dimensional areas within gaseous flows. Aerosolized PrSBeads in carrier gases of varying oxygen concentrations demonstrated point measurement precisions on the order of 0.1%-1%. A charge-coupled device featuring a double image frame ͑DIF͒ feature was used to make spatially resolved pressure measurements within gas phase
... s. Errors on the order of 0.5 atm for one standard deviation were demonstrated when 2 ϫ 2 pixel binning ͑162ϫ 128 pixel overall resolution͒ was used, but improved to 0.003-0.005 atm with the use of 32ϫ 32 pixel binning ͑10ϫ 8 pixel overall resolution͒. Experiments demonstrate the ability to resolve the oxygen concentration differences between a N 2 jet and the surrounding ambient air environment and the ability to measure instantaneous air pressure changes within a square syringe as the plunger is moved in and out. In addition, instantaneous velocity measurements of the airborne PrSBeads in a square syringe were achieved using digital particle image velocimetry at frame rates of 6.4 Hz, thus validating PrSBeads as a tool to simultaneously measure the velocity and pressure within an aerodynamic flow.