High Accuracy, High Temperature Pressure Probes for Aerodynamic Testing

Abstract

This paper presents a ruggedized high accuracy, extremely miniature pressure transducer suitable for numerous applications where size, accuracy and environmental conditions are of critical importance. High transducer accuracy was achieved by using a highly sensitive piezoresistive pressure sensor in conjunction with high resolution digital electronics for sensor output amplification and correction. The paper presents various ways that this transducer can be packaged to make it suitable for flow measurements in both wind tunnels and real world application such as gas turbine engines testing. These methods include miniature differential transducers, miniature 5-hole probes, and pressure rakes. Data from these various configurations are presented showing excellent response over temperature and flow regimes. I. Introduction he technology developed and discussed in this paper was originally developed for Wind Tunnel Applications, where typical flight performance studies using hypervelocity wind tunnel test articles involve the measurement of very low pressures at elevated temperatures. These initial installations were used for static and quasi-static measurements only. After the success 8 of these initial measurements it was decided to extend the use of the sensing and amplifier technologies into the more demanding regime of flow measurements. There are many areas where accurate flow measurement is critical: wind tunnel, ground based engine testing, and flight test can all benefit from high accuracy miniature flow measurement techniques. Many of these applications require both high temperature and high accuracy in order to be useful to the design engineer. We present in this paper a miniature pressure transducer developed specifically to address these instrumentation challenges. Test results are presented and potential benefits, in terms of measurement accuracy and cost savings, are discussed.