Preliminary Estimation of Engine Gas-Flow-Path Size and Weight

Abstract

Subsequent to identifying the optimum engine cycle over a specie ed baseline design mission, one of the important goals of conceptual design is to translate this into an aerothermomechanically compatible gas-e ow-path (GFP) layout and weight estimation. Engine GFP size and weight dee nition are important design parameters. They dee ne the starting point for detailed component design and the physical limits for integration of the engine with the airframe. This paper describes the mathematical basis of engine GFP sizing and weight estimation, as well as their computer simulation, validation, and application to an optimum engine cycle, which will be typical of the next generation of combat aircraft. Nomenclature A = area AR = blade aspect ratio C = chord C/S = blade solidity D = diameter H = height HTR = hub-to-tip ratio K = spool matching parameter k = ratio of specie c heats N = number of blades, rotational speed R = gas constant T = shaft torque U = blade speed W* = compressor loading parameter Y* = turbine loading parameter = stress in the shaft = component efe ciency m = mechanical efe ciency Subscripts B = blade H = hub HP = high pressure HPC = high-pressure compressor HPT = high-pressure turbine i = inner LP = low pressure LPC = low-pressure compressor LPT = low-pressure turbine M = mean o = outer T = tip