Calculation Of Surface Temperatures In Steady Supersonic Flight

Surface temperatures were calculated for bodies in steady supersonic flight at Mach numbers from 2 to 10 and for altitudes from 50,000 and 200,000 feet and emissivities from 0 to 1. The importance of the effects of radiation and convection was determined. It was found, under the assumption of an isothermal atmosphere, that the gain of heat from the air by convection decreases at constant Mach number as the altitude is increased. Equilibrium between convection and radiation is established at temperatures that that consequently decrease as altitude is increased. In general, therefore, at sufficiently high altitudes the surface temperature is considerably less than the stagnation temperature. At a Mach number of 8, for example, the stagnation temperature is 4800 degrees F absolute and the equilibrium surface temperature for an emissivity of 0.5 is 3800 degress F absolute at 50,000 feet and decreases to 1350 degrees F at 200,000 feet.

An approximate method for determining the convective cooling requirement in the laminar-boundary-layer region of a body of revolution in high-speed flight was developed and applied to an example body. The cooling requirement for the example body was determined as a function of Mach number, altitude, size, and a surface-temperature parameter. The maximum value of Mach number considered was 3.0 and the altitudes considered were those within the lower constant-temperature region of the atmosphere (40,000 to 120,000 ft). The extent of the laminar boundary layer was determined approximately at each condition as a function of the variables considered.

This report describes a method that can calculate transient aerodynamic heating and transient surface temperatures at supersonic and hypersonic speeds. This method can rapidly calculate temperature and heating rate time-histories for complete flight trajectories. Semi-empirical theories are used to calculate laminar and turbulent heat transfer coefficients and a procedure for estimating boundary-layer transition is included. Results from this method are compared with flight data from the X-15 research vehicle, YF-12 airplane, and the Space Shuttle Orbiter. These comparisons show that the calculated values are in good agreement with the measured flight data.

This report describes a method that can calculate transient aerodynamic heating and transient surface temperatures at supersonic and hypersonic speeds. This method can rapidly calculate temperature and heating rate time-histories for complete flight trajectories. Semi-empirical theories are used to calculate laminar and turbulent heat transfer coefficients and a procedure for estimating boundary-layer transition is included. Results from this method are compared with flight data from the X-15 research vehicle, YF-12 airplane, and the Space Shuttle Orbiter. These comparisons show that the calculated values are in good agreement with the measured flight data.Quinn, Robert D. and Gong, LeslieArmstrong Flight Research CenterSURFACE TEMPERATURE; COMPUTATION; PROCEDURES; TRANSIENT HEATING; ESTIMATING; SUPERSONIC SPEED; SPACE SHUTTLE ORBITERS; YF-12 AIRCRAFT; BOUNDARY LAYER TRANSITION; HEAT TRANSFER COEFFICIENTS; LAMINAR HEAT TRANSFER; RESEARCH VEHICLES

A real-time heating algorithm was derived and installed on the Ames Research Center Dryden Flight Research Facility real-time flight simulator. This program can calculate two- and three-dimensional stagnation point surface heating rates and surface temperatures. The two-dimensional calculations can be made with or without leading-edge sweep. In addition, upper and lower surface heating rates and surface temperatures for flat plates, wedges, and cones can be calculated. Laminar or turbulent heating can be calculated, with boundary-layer transition made a function of free-stream Reynolds number and free-stream Mach number. Real-time heating rates and surface temperatures calculated for a generic hypersonic vehicle are presented and compared with more exact values computed by a batch aeroheating program. As these comparisons show, the heating algorithm used on the flight simulator calculates surface heating rates and temperatures well within the accuracy required to evaluate flight profiles for acceptable heating trajectories. Quinn, Robert D. and Gong, Leslie Armstrong Flight Research Center RTOP 505-63-31...