Design and Performance of Quick Opening Shock Tube Using Rubber Membrnae. 2nd Report, Modification of the Facility and Analysis of Shock Tube Flow.

Abstract

In the previous paper, the design and performance of a diaphragmless shock tube which could generate, with a higher degree of repeatability, weak shock waves up to shock Mach number of 1.2 were reported. In the present paper, an experimental improvement of the facility, by which the pressure difference between the driver chamber and the driven channel can be increased to about 4 times higher than the previous system, was achieved so that the attainable shock Mach number was extended to Ms=1.6 at the initial atmospheric pressure. Higher shock Mach number up to 3 can also be readily obtained by decreasing the pressure in the driven channel. A numerical simulation and a theoretical analysis were perfomed in order to clarify the characteristics of this diaphragmess shock tube. Although the numerical simulation revealed that the flow near the rubber membrane is very complicated, however, with the help of simplified one-dimensional model, in which the varying cross-section is taken into account, shock Mach numbers achievable in this shock tube were well predicted as a function of the pressure ratio between the high-pressure chamber and low-pressure channel. Good agreement was obtained between the experimental results and theoretical prediction.