Accession Number : ADA303590

Title :   Sealed-Foam, Constrictive-Wrapped, External Insulation System for Liquid-Hydrogen Tanks of Boost Vehicles.

Descriptive Note : Technical note,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

PDF Url : ADA303590

Report Date : MAR 1965

Pagination or Media Count : 157

Abstract : Thermal insulation is required for liquid-hydrogen tanks used on high-energy boost vehicles in order to keep boiloff losses to acceptable values. An investigation was conducted to determine a lightweight hydrogen tank insulation system that would provide adequate thermal insulation during ground hold conditions, and would be able to withstand the aerodynamic forces and heating encountered during the launch trajectory. The experimental investigation included tests of impact sensitivity of the insulation components in the presence of liquid oxygen, aerodynamic tests in which the heating and dynamic pressure conditions were more severe than during a typical launch trajectory, and measurements of the effective thermal conductivity of the insulation by means of (i) small samples, (2) heat-transfer measurements on subscale tanks filled with liquid hydrogen, and (3) heat-transfer measurements on a full-scale insulated Centaur tank filled with liquid hydrogen. The insulation system as finally developed consisted of 0.4-inch thick, 2 lb/cu ft density polyurethane foam panels hermetically sealed within a covering of a foil laminate of Mylar and aluminum. A thin layer of fiber-glass cloth over the insulation provided protection from aerodynamic erosion during launch. The insulation was bonded to the tank wall using adhesive in a grid pattern, primarily to keep air from cryopumping behind the panels. The principal means of holding the insulation on the tank was a prestressed constrictive wrap of fiber-glass roving. This wrap was completely effective in holding the insulation in place under all aerodynamic test conditions including heating in a jet engine exhaust and a wind tunnel test at Mach numbers up to 2.0. (MM)

Descriptors :   *LIQUID ROCKET PROPELLANTS, *LAUNCH VEHICLES, *FOAM, *PROPELLANT TANKS, *THERMAL INSULATION, HEAT TRANSFER, BOOST PHASE, INSULATION, LAMINATES, IMPACT STRENGTH, POLYMERIC FILMS, THERMAL CONDUCTIVITY, AERODYNAMIC FORCES, TANKS(CONTAINERS), FOILS(MATERIALS), MACH NUMBER, LIQUID HYDROGEN, POLYURETHANE RESINS, AERODYNAMIC HEATING, CRYOPUMPING, SEALED SYSTEMS, JET ENGINE EXHAUST, LIQUID OXYGEN, ROCKET LAUNCHERS, ROCKET TRAJECTORIES, BOILOFF, POLYETHYLENE TEREPHTHALATE.

Subject Categories : Plastics
      Thermodynamics
      Rocket Propellants

Distribution Statement : APPROVED FOR PUBLIC RELEASE