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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Design and development of pressure and repressurization purge system for reusable space shuttle multilayer insulation system

Preliminary design and analysis of purge system concepts and purge subsystem approaches are defined and evaluated. Acceptable purge subsystem approaches were combined into four predesign layouts which are presented for comparison and evaluation. Two predesigns were selected for further detailed design and evaluation for eventual selection of the best design for a full scale test configuration. An operation plan is included as an appendix for reference to shuttle-oriented operational parameters.

Source record↗
NASA NTRS1972

Design and development of pressure and repressurization purge system for reusable space shuttle multilayer insulation system

The experimental determination of purge bag materials properties, development of purge bag manufacturing techniques, experimental evaluation of a subscale purge bag under simulated operating conditions and the experimental evaluation of the purge pin concept for MLI purging are discussed. The basic purge bag material, epoxy fiberglass bounded by skins of FEP Teflon, showed no significant permeability to helium flow under normal operating conditions. Purge bag small scale manufacturing tests were conducted to develop tooling and fabrication techniques for use in full scale bag manufacture. A purge bag material layup technique was developed whereby the two plys of epoxy fiberglass enclosed between skins of FEP Teflon are vacuum bag cured in an oven in a single operation. The material is cured on a tool with the shape of a purge bag half. Plastic tooling was selected for use in bag fabrication. A model purge bag 0.6 m in diameter was fabricated and subjected to a series of structural and environmental tests simulating various flight type environments. Pressure cycling tests at high (450 K) and low (200 K) temperature as well as acoustic loading tests were performed. The purge bag concept proved to be structurally sound and was used for the full scale bag detailed design model.

Source record↗
NASA NTRS1978

An ultralightweight, evacuated, load-bearing, high-performance insulation system

A new hollow-glass microsphere insulation and a flexible stainless-steel vacuum jacket were demonstrated on a flight-weight cryogenic test tank, 1.17 m in diameter. The weight of the system is three times lighter than the most advanced vacuum-jacketed design demonstrated to date, a free-standing honeycomb hard shell with a multilayer insulation system (for a Space Tug application). Design characteristics of the flexible vacuum jacket are presented along with a model describing the insulation thermal performance as a function of boundary temperatures and emittance, compressive load on the insulation and insulation gas pressure. Test data are compared with model predictions and with prior flat-plate calorimeter test results. Potential applications for this insulation system or a derivative of this system include the cryogenic Space Tug, the Single-Stage-to-Orbit Space Shuttle, LH2 fueled subsonic and hypersonic aircraft, and LNG applications.

Parmley, R. T.↗
NASA NTRS1973

Analysis of gas flow through a multilayer insulation system.

A theoretical investigation of gas flow inside a multilayer insulation system has been made for the case of the broadside pumping process. A set of simultaneous first-order differential equations for the temperature and pressure of the gas mixture was obtained by considering the diffusion mechanism of the gas molecules through the perforations on the insulation layers. A modified Runge-Kutta method was used for numerical experiment. The numerical stability problem was investigated. It has been shown that when the relaxation time is small compared with the time period over which the gas properties change appreciably, the set of differential equations can be replaced by a set of algebraic equations for solution. Numerical examples were given and comparison with experimental data was made.

Lin, J. T.↗
NASA NTRS1981

Evacuation-induced pressure differentials in multilayer insulation systems

The pressure differentials induced across three types of multilayer insulation systems during evacuation have been measured and compared with values predicted using an idealized parallel plate geometric model. The systems tested were double-aluminized Mylar with a Tissuglas or silk net spacer and crinkled single-aluminized Mylar. Test samples were circular. The influence of purge gas type, layer density, sample diameter, and temperature was systematically investigated. The experimental approach was to measure the absolute pressure history and corresponding pressure differential induced across the insulation during evacuation. The measured pressure differentials were nondimensionalized and compared with those predicted by the parallel plate model as a function of Knudsen number. It was concluded that the parallel plate model is adequate for making engineering analyses. The influence of all parameters, except layer density, is well represented by the model. Representation of the influence of layer density is less satisfactory, but can be improved by modification of the flat plate model to allow for the more obvious practical nonidealities, such as crinkling, or the presence of a net spacer.

Glassford, A. P. M.↗
NASA NTRS2019

Advanced Cryogenic Insulation Systems

New materials in recent decades have enabled advances in thermal insulation systems for storage and transfer of cryogens. To preserve the cold and achieve efficient cryogenic systems, a combination of materials, testing, and engineering is required. The total heat leak into any cryogenic assembly is comprised of three main parts: 1) heat leak through the insulation, 2) heat leak through the support structures, and 3) heat leak attributed to piping penetrations and feedthroughs (and their negative effects on the insulation). This "cold triangle" approach provides a basis for evaluating performance benefits of new materials and analyzing the cost effectiveness in overall system design. Provided are thermophysical data for aerogels, aerogel composites, novel multilayered composites, and glass bubbles for standard test conditions of 293 K and 78 K under conditions from high vacuum to ambient pressure. Examples of cryogenic storage tanks show the relative importance of both insulation and structural materials for achieving designs of highest energy efficiency.

Multilayer Insulation↗
NASA NTRS1978

Comparison of reusable insulation systems for cryogenically-tanked earth-based space vehicles

Three reusable insulation systems concepts were developed for use with cryogenic tanks of earth-based space vehicles. Two concepts utilized double-goldized Kapton (DGK) or double-aluminized Mylar (DAM) multilayer insulation (MLI), while the third utilized a hollow-glass-microsphere, loadbearing insulation (LBI). Thermal performance measurements were made under space-hold (vacuum) conditions for insulating warm boundary temperatures of approximately 291 K. The resulting effective thermal conductivity was approximately 0.00008 W/m-K (W = weight,Kg; m = measured; K = temperature) for the MLI systems (liquid hydrogen test results) and 0.00054 W/m-K for the LBI system (liquid nitrogen test results corrected to liquid hydrogen temperature).

Sumner, I. E.↗
NASA NTRS2010

Thermal Insulation System Analysis Tool (TISTool) User's Manual. Version 1.0.0

The Thermal Insulation System Analysis Tool (TISTool) was developed starting in 2004 by Jonathan Demko and James Fesmire. The first edition was written in Excel and Visual BasIc as macros. It included the basic shapes such as a flat plate, cylinder, dished head, and sphere. The data was from several KSC tests that were already in the public literature realm as well as data from NIST and other highly respectable sources. More recently, the tool has been updated with more test data from the Cryogenics Test Laboratory and the tank shape was added. Additionally, the tool was converted to FORTRAN 95 to allow for easier distribution of the material and tool. This document reviews the user instructions for the operation of this system.

Johnson, Wesley↗