Search NASA⌕ Search

SEARCH · Search NASA

Results for “FLAME PROPAGATION”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1964

Effects of Atmospheric Environment on Electrical Fire Hazards

In general, the problem of electrical fires involves the ignition and flammability parameters relating to the metallic conductor as well as to the insulating materials. The recent study of Klein has approached the problem by using three basic tests: (1) Determining the amount of current that causes wire to burn in various atmospheres, (2) measuring the effect of various atmospheres in propagating flame from a shorted wire to adjacent wires, and (3) measuring the effect of various atmospheres when extreme current is passed through wire.

Roth, Emanuel M.↗
NASA NTRS1970

New type of nonflammable paper

Nonflammable paper is made from fibers of chrysotile asbestos, beta-glass fibers, glass microfibers, and a little nonflammable organic binder. It does not propagate flame in an atmosphere of 16.5-psig oxygen, and it is resistant to rot and mold, making it acceptable as wrapping material and for stored documents.

Armstrong, G. K.↗
NASA NTRS1971

Introduction to program subject: Fireproofing

Various processes for fireproofing materials are discussed. The conditions under which fireproofing measures may be adequate are compared with conditions under which the measures may be inadequate. The mechanisms for flame propagation and conditions required for ignition and burning are described.

Gerstein, M.↗
NASA NTRS1971

The combustion process

The effect of thermodynamic, chemical, and physical properties on the combustion of materials is discussed. The mechanisms which produce and support combustion of various materials are examined. The effects of free radical reactions, convection and gravitational effects on combustion rates, and changes in flame propagation due to size and shape of surfaces are described.

Downs, W. R.↗
NASA NTRS1971

The effects of gravity on flammability

The effects of weightlessness and increased gravity on flammability and flame propagation are discussed. The test equipment and procedures for determining gravity effects are described. Comparisons are made between flammability under normal gravity conditions and occurrences under altered gravity conditions

Pearce, J. P.↗
NASA NTRS1973

An evaluation of the relative fire hazards of jet A and jet B for commercial flight

The relative fire hazards of Jet A and Jet B aircraft fuels are evaluated. The evaluation is based on a consideration of the presence of and/or the generation of flammable mixtures in fuel systems, the ignition characteristics, and the flame propagation rates for the two fuel types. Three distinct aircraft operating regimes where fuel type may be a factor in fire hazards are considered. These are: (1) ground handling and refueling, (2) flight, and (3) crash. The evaluation indicates that the overall fire hazards for Jet A are less than for Jet B fuel.

Hibbard, R. R.↗
NASA NTRS1975

Flammability study of materials in oxygen environments

Report presents flame-propagation rates and flammability ratings of 780 specimens of commercially available plastics, elastomers, coatings, fabrics, and other sheet materials. Test results are also given for over 1970 samples of most commonly used electrical harnesses, connectors, and potting compounds.

Austin, J. G.↗
NASA NTRS1974

Effect of swirling flow on augmentor performance

A test program was conducted with an augmentor which employed swirling flow as a means of promoting rapid flame propagation. The program evaluated the effect of augmentor length, swirl intensity, fuel zoning and Mach number on augmentor performance. Combustion efficiencies near 100% were demonstrated over most of the operating range which extended from an equivalence ratio of 0.2 to over 1.0. The tests were conducted at an inlet temperature of 649 C (1200 F) and at a pressure of 2 atmospheres. The augmentor total pressure losses were typical of current state of the art augmentors.

Clements, T. R.↗
NASA NTRS1976

Gravity effects on flame spreading over solid surfaces

The effects of gravity on the spreading of a flame over a solid combustible surface were determined. Flame propagation rates were measured from specimens of thin cellulose acetate sheets burning in both normal gravity (1 g) and reduced gravity (0 g) environments; the specimens were burned in various quiescent mixtures of oxygen, helium, argon, and nitrogen. A correlation for normal gravity and reduced gravity burning was obtained based on theoretical models of previous investigators.

Andracchio, C. R.↗
NASA NTRS1976

Effect of swirling flow on augmentor performance, phase 2

A test program has been conducted with an augmentor that employed swirling flow as a means of promoting rapid flame propagation. The program measured the trajectory and dispersion of JP-5-type kerosene sprayed into a strongly swirling flowfield. Using the data obtained, a set of sprayrings was designed and evaluated in the augmentor at conditions simulating those typical of augmented turbojet engines. At the inlet test temperature of 649 C the swirling flowfield had no effect on the radial position of the fuel spray. The augmentor demonstrated combustion efficiencies greater than 95% over most of the operating range, which extended from an equivalence ratio of 0.2 to over 1.0.

Clements, T. R.↗
NASA NTRS1976

The effects of forced air flow and oxygen concentration on flammability, smoke density, and pyrolytic toxicity

The question is posed whether forced air flow should be incorporated into flammability tests as a relevant variable. A test apparatus is described which permits tests to be conducted on small test specimens in a forced flow which is (continuously) variable over flow velocities from zero to 300 feet per minute (1.52 m/s). The effects of air-flow rate and oxygen concentration on flame propagation rate, maximum smoke density, and pyrolytic product toxicity were measured for a single material and were statistically evaluated. Regression analysis was used to graph the resulting relationships. It is concluded that air velocity is an important variable for laboratory flammability testing.

Sauers, D. G.↗
NASA NTRS1979

Analytical modeling of flash-back phenomena

To understand the flame flash-back phenomena more extensively, an analytical model was formed and a numerical program was written and tested to solve the set of differential equations describing the model. Results show that under a given set of conditions flame propagates in the boundary layer on a flat plate when the free stream is at or below 1.8 m/s.

Feng, C. C.↗
NASA NTRS1980

Combustion and operating characteristics of spark-ignition engines

The spark-ignition engine turbulent flame propagation process was investigated. Then, using a spark-ignition engine cycle simulation and combustion model, the impact of turbocharging and heat transfer variations or engine power, efficiency, and NO sub x emissions was examined.

Heywood, J. B.↗
NASA NTRS1980

Thermodynamic analysis of turbulent combustion in a spark ignition engine. Experimental evidence

A method independent of physical modeling assumptions is presented to analyze high speed flame photography and cylinder pressure measurements from a transparent piston spark ignition research engine. The method involves defining characteristic quantities of the phenomena of flame propagation and combustion, and estimating their values from the experimental information. Using only the pressure information, the mass fraction curves are examined. An empirical burning law is presented which simulates such curves. Statistical data for the characteristics delay and burning angles which show that cycle to cycle fractional variations are of the same order of magnitude for both angles are discussed. The enflamed and burnt mass fractions are compared as are the rates of entrainment and burning.

Beretta, G. P.↗
NASA NTRS1980

Buoyancy effects on flames spreading down thermally thin fuels

Experiments show that buoyancy influences the downward spread rate of flames consuming thermally thin fuel beds. For index cards (0.0098 cm half-thickness) and adding-machine tape (0.0043 cm half-thickness), an increase in the buoyancy level causes the spread rate to drop until no flame propagation is possible. A dimensionless spread rate is found to correlate with a Damkoehler number. As the Damkoehler number increases with decreasing buoyancy level brought about by an increase in pressure or a decrease in gravity, the dimensionless spread rate approaches unity. It is also found that a small change in orientation with respect to the vertical is equivalent to a change in the magnitude of gravity in the direction of spread, and power-law relations between the dimensional spread rate and pressure are only valid over a small pressure range.

Altenkirch, R. A.↗