Analytical Study of an Axisymmetric Choked Nozzle.

摘要

A simple resonance tube consists of a cavity having the open end axially aligned with a suitable high velocity gas flow field. Under certain flow conditions and for certain geometric configurations, the temperature of the gas trapped in the cavity may exceed substantially the adiabatic stagnation temperature of the driving jet. A rigorous theoretical solution to the complete resonance tube heating phenomenon is an exceedingly complex task. The first step in solving the complete problem was initiated in this investigation by considering the flow field of an axisymmetric jet impinging on a normal plate. A numerical solution of a simplified axisymmetric, unsteady flow was postulated, wherein the driving gas was assumed to be inviscid, thermally-nonconducting and chemically non-reacting. An implicit finite difference scheme was utilized in the development of the computer program. During the contract period, the governing equations of continuity, momentum and energy were formulated for axisymmetric flow and transformed into the 'convservation law' form as required for the Lax-Wendroff technique. The finite-difference equations were obtained, and an appropriate computer program was developed. The initial and boundary conditions for the flow field were postulated, and calculations for both a properly, expanded sonic nozzle and subsonic nozzle were initiated. Instabilities in the calculations were investigated. Recommendations for additional work are proposed. (Author)