Laboratory Study of Space Shuttle Propellant Tank Icing.
AEROSPACE CORP EL SEGUNDO CA AEROPHYSICS LAB
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Small-scale experiments have been performed with SOFI sprayed-on-foam-insulation panels shaved to 0.5- and 0.9-in. thicknesses. The rear sides of the SOFI panels were cooled to LN2 temperatures the front sides were exposed to an environmental chamber with controlled temperature and humidity. The measured rates of frost formation and the observed surface temperatures are consistent with predictions obtained with a simple heat balance model. The measured frost densities, on the other hand, were less than 6 lbcubic feet, much lower than those predicted by the University of Dayton Research Institute frost formation model. In a worst-case test, hard ice was observed when water was dripped down the surface of a 0.5-in.-thic, LN2-chilled SOFI panel. A preliminary study of solar melting produced little rundown or ice. Frost densities of less than 0.1 gcubic centimeter 6 lbcubic feet were obtained, except in the test in which water was dripped onto the surface. Validation by the present experiments of predictions based on a heat balance model applies only to natural convection in the laminar flow regime. A large fraction of the flow on the space shuttle fuel tank will be in the turbulent regime because of the height of the tank. Larger-scale tests would be required to validate the turbulent heat transfer coefficients. Author
- Liquid Rocket Propellants
- Unmanned Spacecraft