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AAE 450: Aero-thermodynamics. Preliminary analysis and literature survey of design concepts for atmospheric Entry of MARS . By Santosh J. Kuruvilla 01/23/2001. Contents:. Vehicle types, characteristics, and requirements for expected mission. Modeling atmospheric flight:
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AAE 450:Aero-thermodynamics Preliminary analysis and literature survey of design concepts for atmospheric Entry of MARS. By Santosh J. Kuruvilla 01/23/2001
Contents: • Vehicle types, characteristics, and requirements for expected mission. • Modeling atmospheric flight: • EOM’s, Stagnation point heat flux calculations,constraints, and assumptions. • Comparison of analysis to existing published data. • Future additions to the model, and required analysis for the given mission. • Related experiences and course work.
Ballistic Lifting Body Vehicle Types • Winged X-24 http://images.jsc.nasa.gov/ Mercury Enterprise • High Heat Load • Poor Booster Compatibility • Low Volume • High Weight • Low Deceleration • High L/D • Horizontal Landings • Low Heat Load • Simple Booster Configuration • Maximum Volume • Low weight • Low L/D • Vertical Landing • Low Heat Load • Good Booster compatibility • High Volume • Relatively Low structural • weight • Moderate Deceleration • Moderate L/D • Horizontal Landing
Mission Requirements • High Volume • Low Weight • Low Heat loading • Hypersonic L/D 0.3 to 1 • Good Booster compatibility • Moderate Controllability using lifting surfaces, to effect plane changes or reduce velocity. = Lifting Body
Dynamic Model for atmospheric flight. Equations from: Hypersonic and planetary entry flight mechanics. By Vinh, Busemann, Culp. • h : Altitude above surface • V: Velocity • : Flight Path angle : Heading angle : Latitude : Longitude • : Bank angle L: Lift D: Drag Rm: Radius of mars : Gravitational Const • EOM’s • Assumptions: • Constant angle of attack • The planet & Atmosphere does not rotate. • mass of vehicle is constant (no thrust) • Density varies exponentially with altitude, scale height of 49km density of 0.00047 kg/m^3. • Ignore Coriolis acceleration
Heat Flux Stagnation point Equations: q:Convective Heat Flux rn: Nose radius V: Free stream velocity Cp: Wall Specific heat coefficient Tw:Wall Temperature : Stefan Boltzmann const. :emissivity • Assumptions: • Valid only for stagnation point • qr Ignored (valid only for LEO entry, I could not find an equation for this)
Future Additions to model • Add altitude and g-force constraints. • Use data to size actual heat shield. • Find acceptable wall temperatures
Related experience and course work • AAE 440, AAE415, AAE 590G, AAE 532, AAE 251 Program Knowledge: MATLAB, FORTRAN77, IRONCAD, CMARC, JPL’s quick.