Langley Aerothermodynamic Facilities Complex - Enhancements and testing capabilities

Micol, John R.

doi:10.2514/6.1998-147

Cited by 103 publications

(73 citation statements)

References 10 publications

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“…Timeaveraged freestream density measurements from 1.7-4.5 K showed good agreement with computed freestream values. Since helium can expand to temperatures as low as 1.7 K without liquefying at the corresponding freestream low pressures, it does not require heating of the stagnation chamber for Mach numbers less than 28 [21].…”

Section: Laser Rayleigh Scattering Studies At Nasa Langley Reseamentioning

confidence: 99%

Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10

Balla

Everhart

2012

AIAA Journal

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In an exploratory investigation, quantitative unclustered laser Rayleigh scattering measurements of density were performed in the air in the NASA Langley Research Center's 31 in. Mach 10 wind tunnel. A review of 20 previous years of data in supersonic and Mach 6 hypersonic flows is presented where clustered signals typically overwhelmed molecular signals. A review of nucleation theory and accompanying nucleation calculations are also provided to interpret the current observed lack of clustering. Data were acquired at a fixed stagnation temperature near 990 K at five stagnation pressures spanning 2.41 to 10.0 MPa (350 to 1454 psi) using a pulsed argon fluoride excimer laser and double-intensified charge-coupled device camera. Data averaged over 371 images and 210 pixels along a 36.7 mm line measured freestream densities that agree with computed isentropic-expansion densities to less than 2% and less than 6% at the highest and lowest densities, respectively. Cluster-free Mach 10 results are compared with previous clustered Mach 6 and condensation-free Mach 14 results. Evidence is presented indicating vibrationally excited oxygen and nitrogen molecules are absorbed as the clusters form, release their excess energy, and inhibit or possibly reverse the clustering process. Implications for delaying clustering and condensation onset in hypersonic and hypervelocity facilities are discussed.

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Section: Laser Rayleigh Scattering Studies At Nasa Langley Reseamentioning

confidence: 99%

Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10

Balla

Everhart

2012

AIAA Journal

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“…Figure 7) is a conventional blow-down facility in which heated, dried, and filtered air is used as the test gas; a detailed description of this facility can be found in Ref. 5. The tunnel has a two-dimensional, contoured nozzle that opens into a 31.0-in.…”

Section: A Compression Pad Wind Tunnel Model Designmentioning

confidence: 99%

Heating Augmentation Due to Compression Pad Cavities on the Project Orion CEV Heat Shield

Hollis

2009

41st AIAA Thermophysics Conference

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An experimental study has been conducted to assess the effects of compression pad cavities on the aeroheating environment of the Project Orion CEV heat-shield. Testing was conducted in Mach 6 and Mach 10 perfect-gas wind tunnels to obtain heating measurements in and around the compression pads cavities using global phosphor thermography. Data were obtained over a wide range of Reynolds numbers that produced laminar, transitional, and turbulent flow within and downstream of the cavities. The effects of cavity dimensions on boundary-layer transition and heating augmentation levels were studied. Correlations were developed for transition onset and for the average cavity-heating augmentation.

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“…This approach is only valid, however, when a linear function is being analyzed. The function in Equation 19 is not linear and when a rst order Taylor series is used, arti cially large errors arise due to the contribution of the adiabatic wall enthalpy. In order to properly compute the errors, higher order terms in the Taylor series expansion must be used.…”

Section: Error Analysismentioning

confidence: 99%

“…Only an initial temperature and a temperature at some time into a tunnel run is required to solve the equation. Thus, in a wind tunnel run, an initial temperature image can be acquired before a run with no ow on the model and then a temperature image can be obtained during a run and Equation 19 can be solved at each pixel in the image. No temperature time history is needed which is important with an imaging method because temperature histories of images would require a large amount of computer storage space.…”

Section: Heat Transfer Theorymentioning

confidence: 99%

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Reduction and analysis of phosphor thermography data with the IHEAT software package

Ronald

1998

36th AIAA Aerospace Sciences Meeting and Exhibit

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Detailed aeroheating information is critical to the successful design of a thermal protection system TPS for an aerospace vehicle. This report describes NASA Langley Research Center's LaRC two-color relative-intensity phosphor thermography method and the IHEAT software package which is used for the e cient data reduction and analysis of the phosphor image data. Development of theory is provided for a new weighted two-color relative-intensity uorescence theory for quantitatively determining surface temperatures on hypersonic wind tunnel models; an improved application of the one-dimensional conduction theory for use in determining global heating mappings; and extrapolation of wind tunnel data to ight surface temperatures. The phosphor methodology at LaRC is presented including descriptions of phosphor model fabrication, test facilities and phosphor video acquisition systems. A discussion of the calibration procedures, data reduction and data analysis is given. Estimates of the total uncertainties with a 95 con dence level associated with the phosphor technique are shown to be approximately 8 to 10 percent in the Langley's 31-Inch Mach 10 Tunnel and 7 to 10 percent in the 20-Inch Mach 6 T unnel. A comparison with thin-lm measurents using two-inch radius hemispheres shows the phosphor data to be within 7 percent of thin-lm measurements and to agree even better with predictions via a LATCH computational uid dynamics solution CFD. Good agreement between phosphor data and LAURA CFD computations on the forebody of a vertical takeo vertical lander con guration at four angles of attack is also shown. In addition, a comparison is given between Mach 6 phosphor data and laminar and turbulent solutions generated using the LAURA, GASP and LATCH CFD codes. Finally, the extrapolation method developed in this report is applied to the X-34 con guration with good agreement b e t w een the phosphor extrapolation and LAURA ight surface temperature predictions. The phosphor process outlined in the paper is believed to provide the aerothermodynamic community with a valuable capability for rapidly obtaining 4 to 5 weeks detailed heating information needed in TPS design.

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Langley Aerothermodynamic Facilities Complex - Enhancements and testing capabilities

Cited by 103 publications

References 10 publications

Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10

Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10

Heating Augmentation Due to Compression Pad Cavities on the Project Orion CEV Heat Shield

Reduction and analysis of phosphor thermography data with the IHEAT software package

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