Development and Characteristic Analysis of a Double Spool Nested Fuel Valve

Lean combustion technology has been widely used recently to reduce emissions from aero-engines. However, it also introduces combustion oscillation, which poses a serious threat to aircraft safety. Active combustion control can effectively suppress combustion oscillation by regulating the fuel flow. However, it also presents significant challenges in terms of high bandwidth, large flow rate, and high power-to-weight ratio for the fuel valve, which are currently unavailable. Therefore, this paper proposes a double spool nested fuel valve, in which two movable spools jointly determine the amplitude of the throttle opening. With the use of a magnetostrictive actuator that drives the inner spool, fast fuel modulation can be achieved. The outer spool, driven by a voice coil motor with a larger stroke, enables more effective regulation of average flow rates. The length of the fuel valve is reduced by utilizing the radial nesting structure of the magnetostrictive actuator and the double spool. Then, the performance of the fuel valve is analyzed and verified through simulation using AMESim and COMSOL. The results indicated that the fuel valve has a bandwidth of up to 1000 Hz and can achieve a flow rate of 23 L/min, despite its compact length of only 139 mm.