As a fundamental consideration in hydraulic control valve dynamics, transientflow through a spool valve has been studied by numerical analysis. The time-dependent stream lines for a suddenly imposed pressure gradient have been shown.The numerical results are used to investigate the variations of flow structure andfluid variables. The numerical analysis of transient flow through a spool valverevealed that the step response of the flow is modeled by an exponential functionwith two distinct characteristic time constants. In order to simulate the dynamicbehavior of the flow rate rapidly, this paper gives a simple formula of equivalentinertial length. The theoretical model shows a good agreement with result fromthe numerical analysis.
