A New Heat Transfer Capability for Application in Hypersonic Flow Using Multiple Schmidt-Boelter Gages

Heat transfer measurements were made on a complex scaled wind tunnel model containing 400 miniature discrete sensors in Hypersonic Wind Tunnels B and C at the Arnold Engineering Development Center AEDC. This test program was significant for a number of reasons which, when combined, have led to the development of a new test capability at the AEDC. First and foremost is the large number of simultaneous thermal measurements made on the wind tunnel test model. The large number of simultaneous measurements on a single test model was primarily driven by the customers desire to conduct the test program in the most cost effective manner. This request was translated into a system to obtain high quality test data points in the least amount of air on time and to make heat transfer measurements on all surfaces of a very complex model. The measurements were made on relatively flat surfaces, wing leading edges, and thin tip fin leading edges multiple measurements were made on a wide variety of unconventional control surfaces and appendages. Simultaneous measurements on the wide variety of surfaces required the selection of a sensor which was highly sensitive, small, and could be contoured to small local surface radii. The sensor chosen for these measurements was the Schmidt Boelter gage. The capability to calibrate Schmidt Boelter gages and compare a National Institute of Standards and Technology NIST traceable and certified standard is one reason this sensor was used for all of the measurements. Since each gage needs the measurement of two thermal parameters to obtain the required measurement parameter, the simultaneous measurement of 800 thermal parameters was required. The previous data acquisition system in these hypersonic wind tunnels at the AEDC was capable of measuring outputs for only 112 Schmidt Boelter gages simultaneously.