HIGH TEMPERATURE RAKE PROBE FOR ARC JET TESTS

THE LACK OF THE CAPABILITY TO ACCURATELY MEASURE FLOW CONDITIONS IN THE ARC JET FACILITIES MAKES THE DATA GATHERED IN THESE FACILITIES QUESTIONABLE. PRESENTLY, ARC JET FLOW CONDITIONS ARE DERIVED. A DISCREPANCY OF 20 TO 50 PERCENT EXISTS BETWEEN THEORETICAL DERIVATIONS OF FREE-STREAM ENTHALPY AND ARC CHAMBER HEAT BALANCE ENTHALPY. THIS MUCH VARIATION INDICATES THAT THERE IS SIGNIFICANT NEED TO BE ABLE TO MEASURE THE FLOW CONDITIONS ACCURATELY SINCE THEORETICAL CALCULATIONS VARY GREATLY. THE DESIGN OF THE RAKE PROBE AND ELEMENTS REQUIRES THAT THEY BE ABLE TO SURVIVE THE SEVERE ENVIRONMENT PRESENT IN AN ARC JET FACILITY. THIS IMPLIES THAT THE ELEMENTS MUST HAVE A VERY RAPID RESPONSE AND THE DATA COLLECTION RATE MUST BE HIGH SO THE TIME THE PROBE IS IN THE FLOW IS MINIMIZED. THE SIZE OF THE FLOW STREAM AND THE NEED TO MINIMIZE THE PROBE COOLING REQUIREMENTS IMPLY THAT THE SIZE OF THE ELEMENTS MUST BE MINIMAL. PHASE I WILL COVER THE BASIC DESIGN OF THE RAKE PROBE AND ITS ELEMENTS AND DEFINE THE MEASUREMENT TECHNIQUES REQUIRED TO MEASURE THE GAS TOTAL ENTHALPY, POST-SHOCK PITOT PRESSURE, FREE-STREAM STATIC PRESSURE, AND FLOW ANGULARITY.