Design and Analysis of Explosively Actuated Valves: The Interaction of the Plunger and the Housing

Abstract

Explosive values are generally composed of a tapered plunger which is explosively driven along the bore of a cylindrical housing and forced to stop at a location designed to alter a particular fluid flow configuration. The stopping point of the plunger is determined primarily by the friction between the plunger and the housing and the axial forces exerted on the taper. One way of calculating these forces is to model the valve as a series of thin disks and to assume an interference fit between the disks of the plunger and the disks of the housing. A previous paper described the modification necessary to account for plastic deformations and strain hardening of nontapered plungers. These modifications are not sufficient when considering tapered hollow plungers. This paper compares the disk model predictions with measured performances and shows that the differences are primarily due to the unusually high pressures developed at the interface between the plunger and the housing. These high pressures are shown to be the result of axial stresses induced by bending of the housing. Likewise, it is shown that the axial stresses induced by the bending of the hollow plunger walls has a significant effect upon the value of the coefficient of friction needed to achieve acceptable simulations.