High heat fluxes measurement in hypersonic wind tunnel tests: comparison among different sensors

The measurement of heat fluxes is one of the key measurement techniques in high enthalpy facilities, since heat fluxes are important quantities for judging the quality of a thermal protection system. Furthermore, heat flux measurements are widely used for flow characterization. The hypersonic plasma wind tunnel Scirocco, at Italian Center for Aerospace Research (CIRA) in Capua (Italy), is a giant facility and can be considered the largest and most powerful in the world in its category. It is characterized by a maximum Mach number equal to 13, and then by high heat fluxes impacting on the test sample. Recently, a probe for stagnation point heat flux measurements, based on a “slug sensor” has been designed and realized. Such a sensor offers great advantages compared with traditional alternatives (Gardon gauge) such as low cost and prolonged durability. The present paper deals with the design, realization and test of this sensor for a test in the Scirocco plasma wind tunnel.The gardon-gauge is compared with the HFM, slugs and calorimeter type sensors, opportunely designed and the advantages and disadvantages of the employed sensors are highlighted