AN ANALYSIS OF CONTROL REQUIREMENTS AND CONTROL PARAMETERS FOR DIRECT-COUPLED TURBOJET ENGINES

摘要

Requirements of an automatic engine control, as affected by engine characteristics, have been analyzed for a direct-coupled turbojet engine. Control parameters for various conditions of engine operation are discussed. A hypothetical engine control is presented to illustrate the use of these parameters.nAn adjustable-speed isochronous governor vas found to offer a desirable method of over-all engine control. The selection of a minimum value of fuel flow was found to offer a means of pre¬venting unstable burner operation during steady-state operation.nUntil satisfactory high-temperature-measuring devices are developed, air-fuel ratio is considered to be a satisfactory acceleration-control parameter for the attainment of the maximum acceleration rates consistent with safe turbine temperatures. No danger of unstable burner operation exists during acceleration if a temperature-limiting acceleration control is assumed to be effective.nDeceleration was found to be accompanied by the possibility of burner blow-out even if a minimum fuel-flow control that pre¬vents burner blow-out during steady-state operation is assumed to be effective. Burner blow-out during deceleration may be elimi¬nated by varying the value of minimum fuel flow as a function of compressor-discharge pressure, but in no case should the fuel flow be allowed to fall below the value required for steady-state burner operation.