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Results for “COMBUSTION WIND TUNNEL”

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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Decomposition of nitric oxide in a hot nitrogen stream to synthesize air for hypersonic wind tunnel combustion testing

A clean source of high enthalpy air was obtained from the exothermic decomposition of nitric oxide in the presence of strongly heated nitrogen. A nitric oxide jet was introduced into a confined coaxial nitrogen stream. Measurements were made of the extent of mixing and reaction. Experimental results are compared with one- and two-dimensional chemical kinetics computations. Both analyses predict much lower reactivity than was observed experimentally. Inlet nitrogen temperatures above 2400 K were sufficient to produce experimentally a completely reacted gas stream of synthetic air.

Zumdieck, J. F.↗
NASA NTRS1988

Finite-rate water condensation in combustion-heated wind tunnels

A quasi-one-dimensional method for computing finite rate nucleation and droplet growth of water in a supersonic expansion of combustion products is presented. Sample computations are included for the Langley 8 foot High Temperature Tunnel, but the method can also be applied to other combustion heated wind tunnels. The sample results indicate that the free stream static pressure can be in the range of 25 to 60 percent greater than that computed for isentropic nozzle flow without water condensation. The method provides a tool for examining the effects of water condensation on static state properties and velocity of the supersonic stream in combustion heated wind tunnels.

Erickson, Wayne D.↗
NASA NTRS1960

A Study of the Combustion of Aluminum Borohydride in a Small Supersonic Wind Tunnel

The combustion of aluminum borohydride in the Mach 2 airstream of a 3.84- by 10-inch wind tunnel was studied by analyzing gas samples taken from the airstream. Gas mixture composition was determined with the aid of a vacuum apparatus and gas chromatograph. The overall combustion efficiency of the fuel was assumed to be good because the combustion efficiency of its hydrogen component was found to be high. The increase of the lateral surface area of the combustion region was dependent upon the degree of mixing of fuel and its combustion products with air. In the flame zone where there was insufficient oxygen for complete combustion, the metal components of the fuel appeared to burn preferentially to the hydrogen component.

Allen, Harrison, Jr.↗
NASA NTRS2019

Infrared Measurements of Forward Heat Conduction during Simulated Microgravity Flame Spread in the Narrow Channel Apparatus

An infrared (IR) camera provides a way of examining temperature trends associated with simulated microgravity flame spread in the Narrow Channel Apparatus (NCA). The IR camera measures the surface temperature of solid poly methyl methacrylate (PMMA) fuel. These tests examine the forward conduction of heat ahead of the flame front in the non-thermally thin fuel.The NCA is a combustion wind tunnel that simulates a microgravity flame spread environment by employing a narrow gap between the fuel and ceiling of the device, limiting the effects of buoyancy. Test conditions of a 5 mm gap, mean opposed flow velocity of 15 cm/s, and fuel thickness of 3 mm are used.PMMA is selected as the fuel due to repeatability of test results, ease of computational modeling, and known combustion mechanics. Using specific lens and bandpass filter combinations the PMMA can be imaged as effectively opaque. The spectral emissivity for PMMA was calculated and incorporated into the calibration of the camera.Surface temperatures from the IR camera are compared to results from thermocouples embedded in the surface of the fuel. The IR camera results show that nontrivial forward conduction occurs during tests, and therefore must be included in computational models of the process.

Berry, Michael↗
NASA NTRS1951

Combustion-chamber Performance Characteristics of a Python Turbine-propeller Engine Investigated in Altitude Wind Tunnel

Combustion-chamber performance characteristics of a Python turbine-propeller engine were determined from investigation of a complete engine over a range of engine speeds and shaft horsepowers at simulated altitudes. Results indicated the effect of engine operating conditions and altitude on combustion efficiency and combustion-chamber total pressure losses. Performance of this vaporizing type combustion chamber was also compared with several atomizing type combustion chambers. Over the range of test conditions investigated, combustion efficiency varied from approximately 0.95 to 0.99.

COMBUSTION - EFFECT OF ENGINE OPERATING CONDITIONS↗
NASA NTRSDate not supplied

Thermal Protection System P50 Cork Char Response Characterization to Ascent Flight Shear and Heating Environments

NASA’s Space Launch System (SLS) experienced deflagration of the acreage of the Core Stage base heat shield during the Green Run hot-fire test campaigns and Artemis I flight. The burning products from the base heat shield during Green Run hot-fire test operation led to concerns in aerothermal environments and thermal protection system (TPS) performance prior to Artemis I flight. Updated design thermal environments accounting for cork combustion were developed using Green Run measurements and assessed prior to Artemis I, resulting in increased TPS thickness for the base heat shield. This work documents a highly controlled ground test within the NASA Marshall Space Flight Center’s Propulsion Test Branch Hot Gas Facility (HGF) and investigates the P50 cork TPS response due to sensitivity changes in radiative heat rates and surface shear stress. Prior to testing at the HGF, most of the P50 cork panels had a thick layer of char due to the cork combustion process replicated in a thermal vacuum chamber. SLS ascent shear stress and heating rate profile were simulated within the HGF by running the combustion-driven wind tunnel at off-nominal conditions and Mach numbers below 1. This test data provided insight into aerothermal measurements from Artemis I flight as well as informing updated base heating design environments for Artemis II. An in-depth understanding of the TPS P50 cork char response and observations is presented for launch vehicle flight ascent environments.

aerothermodynamics↗
NASA NTRS1993

Evaluation of candidate working fluid formulations for the electrothermal-chemical wind tunnel

A new hypersonic test facility which can simulate conditions typical of atmospheric flight at Mach numbers up to 20 is currently under study at the NASA/LaRC Hypersonic Propulsion Branch. In the proposed research, it was suggested that a combustion augmented electrothermal wind tunnel concept may be applied to the planned hypersonic testing facility. The purpose of the current investigation is to evaluate some candidate working fluid formulations which may be used in the chemical-electrothermal wind. The efforts in the initial phase of this research were concentrated on acquiring the code used by GASL to model the electrothermal wind tunnel and testing it using the conditions of GASL simulation. The early version of the general chemical kinetics code (GCKP84) was obtained from NASA and the latest updated version of the code (LSENS) was obtained from the author Dr. Bittker. Both codes are installed on a personal computer with a 486 25 MHz processor and 16 Mbyte RAM. Since the available memory was not sufficient to debug LSENS, for the current work GCKP84 was used.

Akyurtlu, Jale F.↗
DOE OSTI2021

Dynamic infrared gas analysis from longleaf pine fuel beds burned in a wind tunnel: observation of phenol in pyrolysis and combustion phases

Pyrolysis is the first step in a series of chemical and physical processes that produce flammable organic gases from wildland fuels that can result in a wildland fire. We report results using a new time-resolved Fourier transform infrared (FTIR) method that correlates the measured FTIR spectrum with an infrared thermal image sequence, enabling the identification and quantification of gases within different phases of the fire process. The flame from burning fuel beds composed of pine needles (Pinus palustris) and mixtures of sparkleberry, fetterbush, and inkberry plants was the natural heat source for pyrolysis. Extractive gas samples were analyzed and identified in both static and dynamic modes synchronized to thermal infrared imaging: a total of 29 gases were identified including small alkanes, alkenes, aldehydes, nitrogen compounds, and aromatics, most previously measured by FTIR in wildland fires. This study presents one of the first identifications of phenol associated with both pre-combustion and combustion phases using ca. 1 Hz temporal resolution. Preliminary results indicate ~2.5× greater phenol emissions from sparkleberry and inkberry compared to fetterbush, with differing temporal profiles.

09 BIOMASS FUELS↗
NASA NTRS1981

Measuring molecular flows with high-resolution stimulated Raman spectroscopy

It is proposed to use high-resolution stimulated Raman spectroscopy to directly measure high-speed molecular flow velocities in wind tunnels and in combustive chambers. A feasibility study indicates that flow speeds from Mach 0.04 up may be measured with the proposed method using available laser systems. It is pointed out that the success of the proposed technique will make it possible to measure all interesting flow parameters, i.e., species concentration, temperature, and velocity, in a time of less than 1 microsecond at a repetition rate of 10,000/s using a single experimental arrangement.

She, C. Y.↗
NASA NTRS1990

Evaluation of thermal loading on a methane injector at high pressure and temperature

Experimental and numerical analyses are conducted to determine the surface temperature on a methane fuel injector used to produce a high enthalpy test stream for a combustion-fed subscale wind tunnel facility. It was found that the ratio of the methane fuel injection velocity to the air stream velocity is a significant factor in the production of high injector surface temperatures which lead to rapid deterioration of the fuel injector structure. The numerical code utilized for the computational analysis was found to be representative of the experimentally measured data since the experimental trends were reproduced by the numerical simulation. The quantitative accuracy of the numerical predictions could not be assessed from the data gathered because of the difficulty of making a noninterfering injector surface temperature measurement. The numerical code can be used for parametric evaluation of combustor parameters and thus will serve as an important tool in the design of such fuel injector systems.

Harvin, Stephen F.↗
NASA NTRS1993

Computation of hypersonic flows with finite rate condensation and evaporation of water

A computer program for modelling 2D hypersonic flows of gases containing water vapor and liquid water droplets is presented. The effects of interphase mass, momentum and energy transfer are studied. Computations are compared with existing quasi-1D calculations on the nozzle of the NASA Langley Eight Foot High Temperature Tunnel, a hypersonic wind tunnel driven by combustion of natural gas in oxygen enriched air.

Perrell, Eric R.↗