Total Enthalpy Measurement from Blunt Body Gas Cap Emission in Arc-Heated Wind Tunnels: Results and Application
Abstract
At the Air Force Flight Dynamics Laboratory, there has been a continuing program to measure total enthalpy during test conditions in which heating rates are above 5000 BTU/sq ft-sec. Below this level of heating, steady state enthalpy probes and steady state calorimeters can be successfully employed to determine total enthalpy. However, above 5000 BTU/sq ft-sec, in an important region for re-entry testing, the heating is so severe that only 2,3 transient probes can be employed. When using transient probes (calorimeters or enthalpy probes), empirical corrections must be made, and Fay and Riddell's theory must be applied in order to determine total enthalpy. This is complicated by the fact that the enthalpy is not uniform for many test conditions, and may vary across the flow by a factor between 2 and 4. Therefore, the transient probes must have response characteristics of high enough quality to measure an enthalpy distribution, rather than just one value of total enthalpy. This is further complicated by heater unsteadiness effects.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 25, 1972
- Accession Number
- ADA377949
Entities
People
- J. P. Doyle Jr
- L. R. Lawrence Jr.
- R. E. Walterick
- T. M. Weeks
Organizations
- Flight Dynamics Laboratory