Dynamic loads resulting from fuel motion in missile tanks

Abstract

An experimental investigation was conducted with scale models to determine the fuel motion and impact pressures on the fuel tank bulkheads of a missile which result from a sudden change in acceleration from forward to aft. From considerations of dimensional analysis, dynamically similar models were fabricated and tested to simulate a 6-ft diameter, 12-ft long prototype tank. A specially designed, gas operated, test apparatus drove the models through a stroke of about two feet at accelerations ranging from 10 to 50 g which corresponded to prototype decelerations of 0.12 to 0.60 g. High-speed motion pictures of transparent models with both spherical and conical heads, half and quarter full of opaque liquid, were taken corresponding to various accelerations and angles of inclination, and in addition, impact pressures on the heads were measured with flush-mounted pressure cells. The measurements indicate that peak impact pressures are approximately proportional to acceleration, and are greater for inclined rather than vertical motion; the pressures are, however, relatively independent of angle of inclination to the vertical, above a fairly small angle. Pressures are considerably higher on conical than on spherical heads, and are appreciably reduced by tank ring stiffeners.