76 research outputs found
Combustion Limits and Efficiency of Turbojet Engines
Combustion must be maintained in the turbojet-engine combustor over a wide range of operating conditions resulting from variations in required engine thrust, flight altitude, and flight speed. Furthermore, combustion must be efficient in order to provide the maximum aircraft range. Thus, two major performance criteria of the turbojet-engine combustor are (1) operatable range, or combustion limits, and (2) combustion efficiency. Several fundamental requirements for efficient, high-speed combustion are evident from the discussions presented in chapters III to V. The fuel-air ratio and pressure in the burning zone must lie within specific limits of flammability (fig. 111-16(b)) in order to have the mixture ignite and burn satisfactorily. Increases in mixture temperature will favor the flammability characteristics (ch. III). A second requirement in maintaining a stable flame -is that low local flow velocities exist in the combustion zone (ch. VI). Finally, even with these requirements satisfied, a flame needs a certain minimum space in which to release a desired amount of heat, the necessary space increasing with a decrease in pressure (ref. 1). It is apparent, then, that combustor design and operation must provide for (1) proper control of vapor fuel-air ratios in the combustion zone at or near stoichiometric, (2) mixture pressures above the minimum flammability pressures, (3) low flow velocities in the combustion zone, and (4) adequate space for the flame
Knock-limited performance of pure hydrocarbons blended with a base fuel in a full-scale aircraft-engine cylinder III : four aromatics, six ethers
Knock-limited performance of six aromatic amines blended with a base fuel in a full-scale aircraft-engine cylinder
Turbojet Combustor Efficiency with Ceramic-coated Liners and with Mechanical Control of Fuel Wash on Walls
Combustion-efficiency and altitude-limit investigations of five fuels in an annular turbojet combustor
Effect of Fuel Additives on Carbon Deposition in a J33 Single Combustor III : Five Organo-metallic Additives
Effect of fuel additives on carbon deposition in a J33 single combustor : I - three metallic organic additives
Performance of Four Experimental High-btu-per-gallon Fuels in a Single Turbojet Combustor
Performance characteristics of four hydrocarbon fuels having high Btu per gallon were determined in a single turbojet combustor. At simulated low-altitude operating conditions, the fuels with high Btu per gallon generally produced more carbon than did JP-4 and JP-5 fuels. The deposits were reduced appreciably with a fuel-oil additive. At high-altitude conditions, the high Btu-per-gallon fuels gave lower efficiencies than did JP-4 or JP-5 fuels. No attempts were made to improve performance by combustor design modification
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