High Precision Spatially Resolved Fast Luminescent Barometry

摘要

A method for spatially resolved pressure mappings based on laser-induced photoluminescence and fast imaging techniques is described. The method of measurement uses the fact that the luminescence of special organic dye molecules is quenched by oxygen. The luminescence intensity of molecules adsorbed on a surface, in our case on a microstructured and specially prepared aluminum plate, strongly depends on the partial pressure of oxygen. The luminescence of dye molecules was excited by an excimer laser pumped dye laser at 400 nm or by CW UV-lamps. The pressure changes were observed using a gated image intensifier adapted to a CCD camera with a 12-bit resolution. The setup was calibrated by means of reference images obtained at definite pressures. It is shown that calibrated one-dimensional pressure plots can be extracted from the data which have a spatial pressure stability of 1.7 mbar at atmospheric pressure. The time response of the whole system was tested for two different setups. One setup determines the response to first pressure changes, the other is capable of obtaining response to a change in the oxygen partial pressure. The two resulting response times are not nec-essarily equal, and depend on the surface roughness. The response times in the time domain of 1 s show that the method should be efficient for obtaining time resolved data for aerodynamic shock tubes, rotating turbin blades and turbulence effects on surfaces.