Engineering topics

Suchsland, K. E.

Publications and source records attributed to Suchsland, K. E..

3 records

NASA NTRS1977

Arc heater code validation tests of heat shield materials

Results are reported for tests of candidate heat-shield materials for outer-planet entry probes, which were conducted in two different arc-heater facilities at heating rates below those predicted for entry. One facility supplied a combined radiative-convective heating environment in air while the other provided a hydrogen/helium environment for convective heating only. Both 'infinite-slab' and 'finite-slab' models consisting of various carbon phenolic (CP) and fused silica (FS) materials were tested. The test results obtained are expressed in terms of ablation rates and surface as well as in-depth temperature variations with time for the air environment and in terms of normalized ablation rate as a function of temperature for the H/He environment. The measured values are compared with calculations based on a charring material thermal response and ablation code. For the CP models, good agreement between predicted and measured mass-loss rates is noted, surface temperatures in air are predicted within 18%, and in-depth temperature predictions are shown to be conservative in comparison with measured values. For the FS models, discrepancies are found between the predicted and measured mass-loss rates and surface temperatures.

Kesselring, J. P.↗

NASA NTRS1975

Analytic and experimental evaluation of flowing air test conditions for selected metallics in a shuttle TPS application

A detailed experimental and analytical evaluation was performed to define the response of TD nickel chromium alloy (20 percent chromium) and coated columbium (R512E on CB-752 and VH-109 on WC129Y) to shuttle orbiter reentry heating. Flight conditions important to the response of these thermal protection system (TPS) materials were calculated, and test conditions appropriate to simulation of these flight conditions in flowing air ground test facilities were defined. The response characteristics of these metallics were then evaluated for the flight and representative ground test conditions by analytical techniques employing appropriate thermochemical and thermal response computer codes and by experimental techniques employing an arc heater flowing air test facility and flat face stagnation point and wedge test models. These results were analyzed to define the ground test requirements to obtain valid TPS response characteristics for application to flight. For both material types in the range of conditions appropriate to the shuttle application, the surface thermochemical response resulted in a small rate of change of mass and a negligible energy contribution. The thermal response in terms of surface temperature was controlled by the net heat flux to the surface; this net flux was influenced significantly by the surface catalycity and surface emissivity. The surface catalycity must be accounted for in defining simulation test conditions so that proper heat flux levels to, and therefore surface temperatures of, the test samples are achieved.

Schaefer, J. W.↗

NASA NTRS1974

Analytical modeling of intumescent coating thermal protection system in a JP-5 fuel fire environment

The thermochemical response of Coating 313 when exposed to a fuel fire environment was studied to provide a tool for predicting the reaction time. The existing Aerotherm Charring Material Thermal Response and Ablation (CMA) computer program was modified to treat swelling materials. The modified code is now designated Aerotherm Transient Response of Intumescing Materials (TRIM) code. In addition, thermophysical property data for Coating 313 were analyzed and reduced for use in the TRIM code. An input data sensitivity study was performed, and performance tests of Coating 313/steel substrate models were carried out. The end product is a reliable computational model, the TRIM code, which was thoroughly validated for Coating 313. The tasks reported include: generation of input data, development of swell model and implementation in TRIM code, sensitivity study, acquisition of experimental data, comparisons of predictions with data, and predictions with intermediate insulation.

Clark, K. J.↗