High-frequency temperature and pressure probe for unsteady compressible flows

Abstract

A 3-mm-diam, dual hot-wire aspiring probe is described which can simultaneously measure total temperature and total pressure in an unsteady high-speed gas flow. The probe consists of two coplanar constant temperature hot wires at different overheat ratios operated in a 1.5-mm-diam channel with a choked exit. Thus, the constant Mach number flow by the wires is influenced only by free-stream total temperature and pressure. The probe design is a compromise between the conflicting requirements of spatial resolution, frequency response, and angular sensitivity. The dc temperature accuracy of the probe is about 1% while the resolution is 0.3%. Frequency response of the present design is dc to 20 kHz.