Showing papers on "Premixed flame published in 1970"

Flame Spreading Above Liquid Fuels: Surface-Tension-Driven Flows

Abstract: Convective heat transfer through the liquid fuel below a spreading flame is considered as a rate controlling mechanism. Thus, a surface-tension-driven liquid flow, induced by the temperature profile ahead of a spreading flame, is analyzed. Velocities, pressures and surface heights are determined for a two-dimensional flame spreading at a steady rate. It is demonstrated that convection can occur near the suface ahead of the flame and in the direction of propagation and, thus, that liquid-phase convective heat transfer can be a plausible rate-controlling mechanism for flame propagation.

High luminosity burner

Abstract: A method and apparatus for burning, at increased luminosity intensities. A fuel such as natural gas whose combustion is normally characterized by a low luminosity flame. A first hydrocarbon fuel which may include a fixed amount of a free radical promoter is burned in a diffusion flame. The products of this combustion, which include soot particles, are burned along with a second fuel such as natural gas. The flame produced in this secondary combustion has a luminosity greater than that produced by the combustion of said second fuel in a single-stage burner.

Effects of Turbulence on Flame Propagation in Closed Vessel

Abstract: The effects of turbulence on the flame propagation in the propane-air mixture in a closed vessel were investigated by analyzing the high speed motion pictures of flame, the ion-currents due to combustion and the change of the gas compositions in combustion zone. In the combustion chamber, the uniform turbulent conditions were produced by moving suddenly a perforated plate which was driven by the spring and the electro-magnetic control system. The main results are as follows: (1) The combustion zone of turbulent flame may be composed of a lot of flame elements which are similar to laminar flame, and the apparent burning velocity is increased by enlargement of combustion zone due to turbulence. (2) during the early stage following ignition, the flame speed is affected by both factors of mixture strength and intensity of turbulence. with further development of the flame, however, the intensity of turbulence becomes a dominant factor determining thee flame speed.

The stability of flames on flat sprays

Abstract: An investigation into the stabilization of flames on unconfined fuel sprays has been carried out. A simple theoretical model has been set up and analysed on the basis that the controlling fuel/ air mixture ratio for stability is produced by partial drop evaporation in the flame front and air entrained into the spray. The manner in which the conditions for blow-out varied with fuel supply pressure and ambient air velocity was examined and it was found that flame stability increased with drop size. A theoretically derived expression has been used to correlate the position of the flame front with the local air velocity and a characteristic drop diameter.

Nonequilibrium population distributions for vibrational energy levels of CO2 in CO-O2 flames at reduced pressure

Abstract: Carbon dioxide molecular vibrational energy levels above carbon monoxide-oxygen premixed flame, discussing vibration modes leading to population inversion and relaxation time variance

Calculation of Equilibrium Composition and Temperature of a Premixed Flame

Abstract: A Fast and efficient method has been developed to obtain the equilibrium composition of a flame at a given temperature, pressure and mixture strength. The Newton-Raphson iteration technique enables one to solve a set of simultaneous non-linear equations and in the present problem these are the equations relating the equilibrium partial pressures and equilibrium constants for the particular reaction and the conservation of atomic species in reactants and products. A trial solution is used to check the energy balance for the flame at the assumed temperature. The temperature is then suitably altered and the whole procedure is repeated till a reasonable agreement is obtained.

Method of operating a variable flame oxy-fuel burner

Abstract: AN OXY-FUEL BURNER FOR USE IN A METALLURGICAL FURNACE IS DISCLOSED WHICH CAN BE CONTROLLED TO REGULATE THE CONFIGURATION OF THE BURNER FLAME TO PROVIDE A FLAME SHAPE VARYING FROM A WIDE "UMBRELLA" SHAPED FLAME TO A NARROW "PENCIL" SHAPED FLAME. SEVERAL METHODS OF USING SUCH BURNERS IN METALLURGICAL FURNACES ARE ALSO CISCLOSED.

Flame ignition system for cutting machines

Abstract: A method of establishing a self-sustaining high-velocity oxyfuel preheat gas flame comprising pulsating the flow of the preheat gas while igniting same, at a rate such that the average gas velocity is rendered nearly equal to the rate of flame propagation.