Engineering topics

Goodrich, W. D.

Publications and source records attributed to Goodrich, W. D..

At least 19 records

NASA NTRS1985

A sensitivity analysis of the Shuttle Orbiter heating

A procedure for estimating relative sensitivities in Space Shuttle Orbiter entry heating due to variations from nominal flight parameters is presented. Ballpark values are provided for assessing heating changes caused by off-nominal variations in anglle of attack and Reynolds number for laminar flow conditions. Also, a procedure for scaling heating data obtained on subscale models tested at low-enthalpy wind-tunnel test conditions to high-enthalpy flight conditions using simplified flow analysis techniques is presented and verified with flight and wind-tunnel data. In addition, data are presented illustrating that a significant increase in heating was experienced on the fifth Orbiter flight. The increase was possibly caused by changes in the catalytic properties of the Orbiter thermal protection system surface.

Williams, S. D.↗

NASA NTRS1984

Viscous flow effects on hydrogen leaks from cracks in the Orbiter Challenger main engines

An analytical model was developed to provide additional insight and understanding of the factors that influence the simulation and prediction of leak rates from small cracks in pressurized containers. Specifically, the analysis was aimed at developing an analytical model capable of predicting the hydrogen leak rates from a crack in the combustion chamber coolant discharge manifold on main engine 1 of the Orbiter Challenger that was discovered during flight readiness firings 1 and 2. This model was based on viscous pipe flow analyses and calibrated for the crack geometry by using helium leak-rate data obtained from both low- and high-pressure tests used to simulate the flight readiness firing test conditions. In addition, this model includes the effects of crack width changes caused by different working stresses associated with the different test conditions. Because of the combination of the small crack dimensions and the wide range of pressures used for the test conditions, either laminar or turbulent viscous effects dominated the flows at all test conditions. This model was used to illustrate the sensitivity of the predicted leak rates to considerations of test conditions, viscous flow effects, and geometric features of the crack. In addition, the model was certified by comparing the hydrogen leak-rate prediction for the flight readiness firing test condition to the actual measured leak rate. The prediction was within 9 percent of the measured value.

Goodrich, W. D.↗

NASA NTRS1983

Shuttle orbiter boundary layer transition at flight and wind tunnel conditions

Hypersonic boundary layer transition data obtained on the windward centerline of the Shuttle orbiter during entry for the first five flights are presented and analyzed. Because the orbiter surface is composed of a large number of thermal protection tiles, the transition data include the effects of distributed roughness arising from tile misalignment and gaps. These data are used as a benchmark for assessing and improving the accuracy of boundary layer transition predictions based on correlations of wind tunnel data taken on both aerodynamically rough and smooth orbiter surfaces. By comparing these two data bases, the relative importance of tunnel free stream noise and surface roughness on orbiter boundary layer transition correlation parameters can be assessed. This assessment indicates that accurate predications of transition times can be made for the orbiter at hypersonic flight conditions by using roughness dominated wind tunnel data. Specifically, times of transition onset and completion is accurately predicted using a correlation based on critical and effective values of a roughness Reynolds number previously derived from wind tunnel data.

Goodrich, W. D.↗

NASA NTRS1983

Shuttle Orbiter boundary-layer transition - A comparison of flight and wind tunnel data

Hypersonic boundary-layer transition data obtained on the windward centerline of the Shuttle Orbiter during entry for the first four flights are presented and analyzed. Because the Orbiter surface is composed of a large number of thermal protection tiles, the transition data include the effects of distributed roughness arising from tile misalignment and gaps. These data are used as a benchmark for assessing and improving the accuracy of boundary-layer transition predictions based on correlations of wind tunnel data taken on both aerodynamically rough and smooth Orbiter surfaces. By comparing these two data bases, the relative importance of tunnel free-stream noise and surface roughness on Orbiter boundary-layer transition correlation parameters can be assessed. This assessment indicates that accurate predictions of transition times can be made for the Orbiter at hypersonic flight conditions by using roughness dominated wind tunnel data. Specifically, times of transition onset and completion can be accurately predicted using a correlation based on critical and effective values of a roughness Reynolds number previously derived from wind tunnel data.

Goodrich, W. D.↗

NASA NTRS1982

Space Shuttle orbiter entry heating and TPS response: STS-1 predictions and flight data

Aerothermodynamic development flight test data from the first orbital flight test of the Space Transportation System (STS) transmitted after entry blackout is given. Engineering predictions of boundary layer transition and numerical simulations of the orbiter flow field were confirmed. The data tended to substantiate preflight predictions of surface catalysis phenomena. The thermal response of the thermal protection system was as expected. The only exception is that internal free convection was found to be significant in limiting the peak temperature of the structure in areas which do not have internal insulation.

Ried, R. C.↗

NASA NTRS1981

Comparison of correlations of Shuttle boundary-layer transition due to distributed roughness

The transition criteria for the windward surface of the Shuttle Orbiter, which is composed of a large number of thermal protection tiles, must include the effect of distributed roughness arising from joints and possible tile misalignments. Theoretical flow-field parameters and heat-transfer distributions were used to analyze boundary-layer transition data. Data were obtained for Mach numbers from 8 to 12 over a Reynolds number range from 1.8 million to 17.6 million with surface temperatures from 0.114 to 0.435 T sub t. The transition correlations were approximately the same both for the misaligned-tile models and for the grit-roughened model. The incipient value Re sub K, tr was 15, the critical value was 85, the effective value was 190.

Bertin, J. J.↗

NASA NTRS1980

Aerodynamic heating for gaps in laminar and transitional boundary layers

The presence of gaps, slots, and/or steps in a surface may significantly perturb a supersonic boundary layer. The paper discusses heat-transfer distributions for a variety of gap configurations which were obtained by placing instrumented inserts in a flat-plate structural carrier. The data were obtained in a 3.50 foot hypersonic wind tunnel at a freestream Mach number of 5.10 over a range of Reynolds number from 2,570,000 to 8,110,000. The variables of the test program included the freestream Reynolds number and the gap configuration, e.g., width, depth, step height, number, and orientation.

Bertin, J. J.↗

NASA NTRS1980

Effects of aerodynamic heating and TPS thermal performance uncertainties on the Shuttle Orbiter

A procedure for estimating uncertainties in the aerodynamic-heating and thermal protection system (TPS) thermal-performance methodologies developed for the Shuttle Orbiter is presented. This procedure is used in predicting uncertainty bands around expected or nominal TPS thermal responses for the Orbiter during entry. Individual flowfield and TPS parameters that make major contributions to these uncertainty bands are identified and, by statistical considerations, combined in a manner suitable for making engineering estimates of the TPS thermal confidence intervals and temperature margins relative to design limits. Thus, for a fixed TPS design, entry trajectories for future Orbiter missions can be shaped subject to both the thermal-margin and confidence-interval requirements. This procedure is illustrated by assessing the thermal margins offered by selected areas of the existing Orbiter TPS design for an entry trajectory typifying early flight test missions.

Goodrich, W. D.↗

NASA NTRS1977

Effects of scaled heatshield tile misalignment on Orbiter boundary-layer transition

The article addresses the problem of assessing the sensitivity of the heat transfer rate of a Space Orbiter windward surface and boundary-layer transition data to surface features, or 'roughness elements', characteristic of randomly misaligned heat shield tiles. Selected heat shield tiles were precision-formed on the surface of a 0.0175-scale Orbiter model. Selective electroless plating and selective electrochemical etching techniques were employed. Effects of roughness on the location of boundary-layer transition were markedly influenced by the wall-to-total temperature ratios, according to wind-tunnel test results.

Goodrich, W. D.↗

NASA NTRS1977

Effect of surface cooling and roughness on transition for the Shuttle Orbiter

An analysis of roughness-induced boundary-layer transition examines the sensitivity of the Orbiter boundary-layer transition criteria to surface cooling, to surface roughness, and to the assumed flow-field model. The experimental data were obtained using a 0.0175-scale Orbiter with surface roughness represented by misaligned heat-shield tiles for surface temperatures from 0.12 stagnation temperature (a value typical of entry conditions) to 0.42 stagnation temperature (a value typical of continuous-flow wind-tunnels). Tile misalignment had only a slight effect on the heat transfer and on the trasition locations for wall temperature = 0.42 stagnation temperature. Cooling the boundary layer caused the tile-induced disturbances to increase significantly, promoting premature transition. Correlation of the effects of the misalignment height and of surface cooling in promoting transition are presented and predictions are made for typical Orbiter entry conditions.

Bertin, J. J.↗

NASA NTRS1977

One-wire thermocouple

Nickel alloy/constantan device accurately measures surface temperature at precise locations. Device is moderate in cost and simplifies fabrication of highly-instrumented seamless-surface heat-transfer models. Device also applies to metal surfaces if constantan wire has insulative coat.

Goodrich, W. D.↗

NASA NTRS1977

Aluminum transfer method for plating plastics

Electroless plating technique produces plate of uniform thickness. Hardness and abrasion resistance can be increased further by heat treatment. Method results in seamless coating over many materials, has low thermal conductivity, and is relatively inexpensive compared to conventional methods.

Goodrich, W. D.↗

NASA NTRS1976

Engineering flowfields and heating rates for highly swept wing leading edges

An engineering flow model is developed (and verified experimentally) which describes the flowfield that arises when a supersonic stream encounters a wedge/cylinder configuration whose angles are such that the flow includes only weak shock waves. A numerical code using the perfect gas relations is used to describe the flow in the plane of symmetry inboard of the shock interaction region. Theoretical surface-pressure and heat-transfer distributions are computed for freestream velocities ranging from 1167 to 7610 m/sec. Nondimensionalization of the heat-transfer rates in terms of local flow parameters produced a correlation of Stanton number as a function of the local Reynolds number, which is independent of the freestream flow conditions and of the surface temperature.

Bertin, J. J.↗

NASA NTRS1976

Numerical computations of Orbiter flow fields and heating rates

Numerical computations of flow fields around an analytical description of the Space Shuttle Orbiter windward surface, including the root of the wing leading edge, are presented to illustrate the sensitivity of these calculations to several flow field modeling assumptions. Results of parametric flow field and boundary layer computations using the axisymmetric analogue concept to obtain three-dimensional heating rates, in conjunction with exact three-dimensional inviscid floe field solutions and two-dimensional boundary layer analysis - show the sensitivity of boundary layer edge conditions and heating rates to considerations of the inviscid flow field entropy layer, equilibrium air versus chemically and vibrationally frozen flow, and nonsimilar terms in the boundary layer computations. A cursory comparison between flow field predictions obtained from these methods and current Orbiter design methods has established a benchmark for selecting and adjusting these and future design methodologies.

Goodrich, W. D.↗

NASA NTRS1976

Effects of surface temperature and Reynolds number on heat transfer to the Shuttle Orbiter leeward fuselage

Heat-transfer data obtained at hypersonic shock tunnel conditions and three-dimensional flow field computations were used to study the influence of surface temperature and Reynolds number on the heating experienced by the leeward fuselage area of the Space Shuttle Orbiter configuration. The basic results of this study indicate that systematic variations in the average total enthalpy within a boundary layer (as obtained through controlled nonadiabatic processes) has an influence on the heat transfer to downstream areas which can be correlated; even in three-dimensional separated flow areas. Specifically, the average separated-flow Stanton number for the fuselage leeward surface is shown to be moderately dependent on the windward-wall to free-stream total temperature ratio.

Bertin, J. J.↗

NASA NTRS1976

Aeroheating model advancements featuring electroless metallic plating

Discussed are advancements in wind tunnel model construction methods and hypersonic test data demonstrating the methods. The general objective was to develop model fabrication methods for improved heat transfer measuring capability at less model cost. A plated slab model approach was evaluated with cast models containing constantan wires that formed single-wire-to-plate surface thermocouple junctions with a seamless skin of electroless nickel alloy. The surface of a space shuttle orbiter model was selectively plated with scaled tiles to simulate, with high fidelity, the probable misalignments of the heatshield tiles on a flight vehicle. Initial, Mach 8 heating results indicated a minor effect of tile misalignment roughness on boundary layer transition, implying a possible relaxation of heatshield manufacturing tolerances. Some loss of the plated tiles was experienced when the model was tested at high heating rates.

Stalmach, C. J., Jr.↗

NASA NTRS1976

Hypersonic heat-transfer and transition correlations for a roughened shuttle orbiter

The effect of roughness on the heat transfer distributions and the transition criteria for the windward pitch plane of the shuttle orbiter at an angle of attack of 30 deg was studied using data obtained in hypersonic wind tunnels. The heat transfer distributions and the transition locations for the roughened models were compared with the corresponding data for smooth models. The data were correlated using theoretical solutions for a nonsimilar, laminar boundary layer subject to two different flow field models for the orbiter.

Bertin, J. J.↗

NASA NTRS1974

Analysis of high-velocity and real-gas effects on the shock-interference pattern for delta-wing orbiters

Numerical solutions have been generated to study the two-dimensional flow field which results when supersonic flow encounters double-wedge configurations whose angles are such that a Type VI pattern occurs. Two numerical codes were developed: one which used the perfect-gas relations (including the ability to vary gamma to 'simulate' real-gas effects) and a second which incorporated a Mollier table to define equilibrium air properties. Theoretical surface-pressure and heat-transfer distributions in the interaction perturbed region along the simulated 'wing-leading edge' were obtained for velocities from 1167 m/sec to 7610 m/sec.

Bertin, J. J.↗