A fluidic fuel control system for an advanced ramjet engine

Abstract

The continuing need for new cont ro l systems exhibit ing higher r e l i a b i l i t y and efficiency under extreme environments accompanied by the need ror weight and space reductions has spurred the app l ica t ion of f l u i d i c technology t o advanced ramjet engine control systems. The requirements fo r the control system of a typ ica l subsonic combustion ramjet were established and used t o design a Pluid ic fuel control system. The system consisted of a f u e l mass flow r a t e sensor (fixed impedance type), an a i r mass flow r a t e sensor (variable i m pedance), an equivalence r a t i o computer, and a f u e l t h r o t t l i n g valve. The variable impeoance sensor u t i l i z e s d i g i t a l f l u id i c amplifiers ( f l i p f lops ) and a vortex t h r o t t l i n g valve i n a limit-cycle operation. before inte&rstion i n t o a breadboard model. The integrated system was tes ted with a i r simulating the f u e l and with t h e prospective propellants of the advanced ramjet ( a i r and hydrogen). With the exception of the mechanical f u e l valve, all components performed within t h e established spec i f icat ions. The f u e l cont ro l system successml ly metered the f u e l over the e n t i r e ranges of a i r flow, engl.ne i n l e t t o t a l pressure, and engine e x i t i m pedance i n accordance with the equivalence r a t i o command which was inserted mechanically in to the equivalence r a t i o computer. %e components were tested individually