Effect of Spool Shape Design on Gas Turbine Engine Electro-Hydraulic Valve Performance

Abstract

The main parts of the gas turbine engine are the compressor, combustor, turbine, and control units. Sometimes the ground equipment gas turbine engine encounters a problem in the control unit that can badly affect the engine's performance at different operating regimes. Consequently, a drastic decrease in engine life time and reliability is noticed. The main affecting parameters are the air control system, combustion, and compression systems of the gas turbine engine. Therefore, the air flow control system is one of the important parameters that affect the gas turbine engine's dynamic performance. So, the dynamic performance of the engine air control system has to be investigated. Controlling the dynamic performance of the engine air control system relies; heavily on electrohydraulic systems. Among the most common and challenging problems with electrohydraulic control systems is investigating the effect of changing the design geometry, including shapes, of their components.

An example would be the spool in an Electro-Hydraulic Servo Valve (EHSV) in a turboshaft engine. A detailed analysis of a fuel-based electrohydraulic position control device was presented here in this paper. To assess the implications of shape modifications on the dynamic performance of the system behaviour, three distinct shapes for this spool were presented. ANSYS FLUENT 19.2 was used for modelling and CFD study of the three shapes of the spool at four different openings. The outcomes were compared with each other.

The results showed that using a three-step spool is a better design and selection than using one or two steps. There was a reduction in pressure resonance and a smoothing of the velocity of the fluid inside the valve. So, the dynamic performance of the valve will be improved by reducing the pressure resonance and reducing the jet of fluid flow at the valve inlet, vortices, and smoothness in the moving spool. Also, the performance of the IGV will be improved. As a result, good dynamic performance of the gas turbine will be obtained.