Basic Principles – Gas Turbine Compatibility – Intake Aerodynamic Aspects

Engine/intake compatibility covers the mutual dependencies between the aircraft intake and the gas turbine. Flow physical effects in both the intake and/or the gas turbine can reduce stability margins of the propulsion system dramatically, possibly resulting in unstable performance or engine flameout. Besides exhibiting optimal performance it is of utmost importance that stable propulsion operation in the whole flight envelope of a jet aircraft is ensured. In this chapter, the sources of possible intake flow distortions will be described. The state of the art for the quantification of intake flow distortion by the use of distortion parameters is presented together with possible methods for measuring the data for the calculation of these parameters. Existing experience and current research efforts with the aim of reducing flow distortion in intakes are highlighted. Keywords: intake/engine compatibility; intake distortion; stall; surge; compressor; total pressure distortion; temperature distortion; swirl distortion; surge margin; distortion descriptor