scispace - formally typeset
Search or ask a question
Proceedings ArticleDOI

Aerothermodynamic measurement and prediction for a modified orbiter at Mach 6 and 10 in air

01 Jun 1991-Vol. 32, Iss: 5
TL;DR: In this paper, heat transfer rate distributions measured laterally over the windward surface of an orbiter-like configuration using thin-film resistance heat-transfer gauges and globally using the newly developed relative intensity, two-color thermographic phosphor technique are presented for Mach 6 and 10 in air.
Abstract: Detailed heat-transfer rate distributions measured laterally over the windward surface of an orbiter-like configuration using thin-film resistance heat-transfer gauges and globally using the newly developed relative intensity, two-color thermographic phosphor technique are presented for Mach 6 and 10 in air. The angle of attack was varied from 0 to 40 deg, and the freestream Reynolds number based on the model length was varied from 4 x 10(exp 5) to 6 x 10(exp 6) at Mach 6, corresponding to laminar, transitional, and turbulent boundary layers; the Reynolds number at Mach 10 was 4 x 10(exp 5), corresponding to laminar flow. The primary objective of the present study was to provide detailed benchmark heat-transfer data for the calibration of computational fluid-dynamics codes. Predictions from a Navier-Stokes solver referred to as the Langley aerothermodynamic upwind relaxation algorithm and an approximate boundary-layer solving method known as the axisymmetric analog three-dimensional boundary layer code are compared with measurement. In general, predicted laminar heat-transfer rates are in good agreement with measurements.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, the effects of discrete and distributed roughness elements on boundary layer transition, which included trip height, size, location, and distribution, both on and off the windward centerline, were investigated.
Abstract: Boundary layer and aeroheating characteristics of several X-33 configurations have been experimentally examined in the Langley 20-Inch Mach 6 Air Tunnel. Global surface heat transfer distributions, surface streamline patterns, and shock shapes were measured on 0.013-scale models at Mach 6 in air. Parametric variations include angles-of-attack of 20-deg, 30-deg, and 40-deg; Reynolds numbers based on model length of 0.9 to 6.6 million; and body-flap deflections of 0, 10 and 20-deg. The effects of discrete and distributed roughness elements on boundary layer transition, which included trip height, size, location, and distribution, both on and off the windward centerline, were investigated. The discrete roughness results on centerline were used to provide a transition correlation for the X-33 flight vehicle that was applicable across the range of reentry angles of attack. The attachment line discrete roughness results were shown to be consistent with the centerline results, as no increased sensitivity to roughness along the attachment line was identified. The effect of bowed panels was qualitatively shown to be less effective than the discrete trips; however, the distributed nature of the bowed panels affected a larger percent of the aft-body windward surface than a single discrete trip.

110 citations

Journal ArticleDOI
TL;DR: The effect of isolated roughness on the windward surface boundary layer of the Shuttle Orbiter has been experimentally examined in the NASA Langley Research Center 20-InchMach 6 Tunnel as discussed by the authors.
Abstract: The effect of isolated roughness on the windward surface boundary layer of the Shuttle Orbiter has been experimentally examined in the NASA Langley Research Center 20-InchMach 6 Tunnel. The size and location of isolated roughness elements (intended to simulate raised ormisalignedShuttleOrbiter Thermal Protection System tiles and protruding gap Ž ller material) were varied to systematically examine the response of the boundary layer. Global heat transfer images of the windward surface of a 0.75%-scaleOrbiter at an angle of attack of 40 deg were obtained over a range of Reynolds numbers using phosphor thermography and were used to infer the status of the boundary layer. Computationalpredictions were performed to provide both laminar and turbulent heating levels for comparison to the experimental data and to provide  owŽ eld parameters used for investigatingboundary-layer transition correlations. A variety of roughness heights and locations along the windward centerline were used. The roughness-transition correlation, using the predicted edge parameters Re /Me and k/ , was well behaved. The off-centerline results illustrate the potential for an asymmetric transition pattern to be isolated to one side of the vehicle, thereby causing the increased yawing moments experienced in  ight.

76 citations

Journal ArticleDOI
TL;DR: In this paper, an axisymmetric analog for three-dimensional boundary layers and a generalized body-fitted coordinate system are used to calculate heating rates on 3D vehicles at angle of attack.
Abstract: An approximate method for calculating heating rates on three-dimensional vehicles at angle of attack is presented. The method is based on the axisymmetric analog for three-dimensional boundary layers and uses a generalized body-fitted coordinate system. Edge conditions for the boundary-layer solution are obtained from an inviscid flowfield solution, and because of the coordinate system used, the method is applicable to any blunt body geometry for which an inviscid flowfield solution can be obtained. The method is validated by comparing with experimental heating data and with thin-layer Navier-Stokes calculations on the shuttle orbiter at both wind-tunnel and flight conditions and with thin-layer Navier-Stokes calculations on the HL-20 at wind-tunnel conditions.

73 citations

Proceedings ArticleDOI
01 Jan 1998
TL;DR: A status review of the experimental and computational work performed to support the X-33 program in the area of hypersonic boundary-layer transition is presented in this article, where global transition fronts are visualized using thermographic phospor measurements.
Abstract: A status review of the experimental and computational work performed to support the X-33 program in the area of hypersonic boundary-layer transition is presented. Global transition fronts are visualized using thermographic phospor measurements. Results are used to derive transition correlations for "smooth body" and discrete roughness models and a computational tool is developed to predict transition onset for X-33 using these correlations. The X-33 thermal protection system appears to be conservatively designed based on these models. Additional study is needed to address concerns related to surface waviness before final conclusions can be made. A discussion of future test plans is included.

51 citations

Journal ArticleDOI
TL;DR: In this paper, an overview of the hypersonic aeroheating wind tunnel test program conducted at the NASA Langley Research Center in support of one of these vehicles, the X-34 small reusable technology demonstrator program, is presented.
Abstract: Critical technologies are being developed to support the goals of the NASA Office of Aeronautics and Space Transportation Technology Access to Space initiative for next-generation reusable space transportation systems. From the perspective of aerothermodynamic performance throughout the flight trajectory, the Reusable Launch Vehicle program incorporates conceptual analysis, ground-based testing, and computational fluid dynamics to provide flyable suborbital flight demonstrator vehicles. This report provides an overview of the hypersonic aeroheating wind tunnel test program conducted at the NASA Langley Research Center in support of one of these vehicles, the X-34 small reusable technology demonstrator program. Global surface heat transfer images, surface streamline patterns, and shock shapes were measured on 0.0153- and 0.0183-scale models of proposed X-34 flight vehicles at Mach 6 and 10 in air. The primary parametrics that were investigated include angles-of-attack from 0 to 35 deg. and freestream unit Reynolds numbers from 0.5 to 8 million per foot (which was sufficient to produce laminar, transitional, and turbulent heating data), both with and without control surface deflections. Comparisons of the experimental data to computational predictions are included, along with a discussion of the implications of some of the experimental flow features for the flight vehicle.

44 citations

References
More filters
Journal ArticleDOI
TL;DR: In this paper, Laminar and turbulent heating-rate equations appropriate for engineering predictions of the convective heating rates about blunt reentry spacecraft at hypersonic conditions were developed, applicable to both nonreacting and reacting gas mixtures for either constant or variable-entropy edge conditions.
Abstract: Laminar and turbulent heating-rate equations appropriate for engineering predictions of the convective heating rates about blunt reentry spacecraft at hypersonic conditions are developed. The approximate methods are applicable to both nonreacting and reacting gas mixtures for either constant or variable-entropy edge conditions. A procedure which accounts for variable-entropy effects and is not based on mass balancing is presented. Results of the approximate heating methods are in good agreement with existing experimental results as well as boundary-layer and viscous-shock-layer solutions.

149 citations

Proceedings ArticleDOI
01 Jan 1991
TL;DR: A relative intensity phosphor thermography technique developed for surface heating studies in hypersonic wind tunnels is described in this article, where a direct relationship between relative emission intensity and phosphor temperature is used for quantitative surface temperature measurements in time.
Abstract: A relative-intensity phosphor thermography technique developed for surface heating studies in hypersonic wind tunnels is described. A direct relationship between relative emission intensity and phosphor temperature is used for quantitative surface temperature measurements in time. The technique provides global surface temperature-time histories using a 3-CCD (Charge Coupled Device) video camera and digital recording system. A current history of technique development at Langley is discussed. Latest developments include a phosphor mixture for a greater range of temperature sensitivity and use of castable ceramics for inexpensive test models. A method of calculating surface heat-transfer from thermal image data in blowdown wind tunnels is included in an appendix, with an analysis of material thermal heat-transfer properties. Results from tests in the Langley 31-Inch Mach 10 Tunnel are presented for a ceramic orbiter configuration and a four-inch diameter hemisphere model. Data include windward heating for bow-shock/wing-shock interactions on the orbiter wing surface, and a comparison with prediction for hemisphere heating distribution.

102 citations

Journal ArticleDOI
TL;DR: In this article, the code calibration program for the Langley Aerothermodynamic Upwind Relaxation Algorithm to be used as support for the Aero-assist Flight Experiment (AFE) is discussed.
Abstract: The code calibration program for the Langley Aerothermodynamic Upwind Relaxation Algorithm to be used as support for the Aeroassist Flight Experiment (AFE) is discussed. Comparisons between experimental data and numerical simulations are made which focus on perfect-gas tests involving a scale model of the AFE. Aspects of the thermochemical nonequilibrium model are called into question by the results of ground tests performed in a ballistic range and in a shock tunnel.

88 citations