Development of Surface Junction Thermocouples for High Enthalpy Measurements Available to Purchase

Among the fundamental data needed to be acquired in hypersonic experiments with energy deposition to the flow are the heat transfer rates to the model. Such task is not easily accomplished though, due to several factors relative to flow characteristics, such as high enthalpy, high ionization and electrical conductivity, abrasion on the model’s surface and short time available to conduct the tests in shock tunnels (tenths of microseconds to a couple of milliseconds). Low cost surface junction thermocouples were constructed and calibrated to obtain the transient heat transfer, consisting of a E‐type coaxial thermocouple element, a filtering and amplifying circuitry developed to provide low noises and a strong signal, and a data acquisition system. The gage was tested and calibrated using IEAv’s Tl shock tunnel, demonstrating it’s capability to respond in pronto and withstand the test conditions. These sensors will be used to measure the heat transfer rates in the Directed Energy Air‐Spike (DEAS) concept in future shock tunnel experiments.