Portal de Periódicos da CAPES

Flight Measurements of Aerodynamic Heating and Boundary Layer Transition on the Viking 10 Nose Cone

1955; American Institute of Aeronautics and Astronautics; Volume: 25; Issue: 12 Linguagem: Inglês

10.2514/8.6860

1936-9980

R. Snodgrass,

Rocket and propulsion systems research

JET aircraft and missiles are now flying at velocities high enough in the supersonic regime to experience an excessive rise in surface temperature due to the conversion of some of the kinetic energy of the vehicle into heat by compression and friction in the boundary layer. To prevent this thermal barrier from setting an upper limit on plane and missile performance, it is necessary to be able to predict this temperature rise for a particular design configuration in order that structural failure, melting, fuel evaporation, and other thermal barrier effects can be prevented in the final design. At present, it is very difficult to predict the temperature rise on a particular plane or missile. Because of the urgency of the problem, much recent theoretical work has been done on aerodynamic heating, but relatively little flight data— particularly at high Mach numbers—have been available for correlation with theoretical prediction. The experiment performed in Viking 10 on May 7, 1954, was designed to add to the small store of flight measurements of aero-heating and free-flight boundary layer transition. In order to predict this in-flight temperature rise, it is necessary to know the temperature recovery factor, the local heat-transfer coefficient, and the conditions for boundary layer transition. Except for the work of Fischer and Norris (l) on V-2 rockets No. 19 and No. 27, Sternberg (2) on V-2 No. 61, and NACA (3), very few free-flight measurements of heat transfer coefficients under transient flight conditions have been made. Most of the experimental investigations of boundary layer transition have been conducted in wind tunnels, (e.g., Czarnecki and Sinclair, NACA RM L53I18a) where there is reason to believe that local shocks, tunnel turbulence level, and angularity of the tunnel airstream may affect the supersonic transition data. The object of the present study was to correlate the state of the boundary layer determined from flight data with the Van Driest condition for complete stability of the laminar boundary layer (4). Local supersonic convective heat-transfer coefficients, derived from resistance-thermometer measurements at twentytwo points on the inner surface of the Viking No. 10 nose cone, were correlated nondimensionally with current theoretical solutions and found to agree within the accuracy of measurement. The ratio of measured wall temperature to local stream temperature was plotted vs. local Mach number for turbulent, transition, and laminar flow, and the Van Driest