Interaction of a moving shock wave with a two-phase reacting medium

Abstract

The flow field, that develops when a moving shock wave hits a two-phase medium of gas and particles, has a practical application to industrial accidents such as explosions at coal mine and in grain elevator and furthermore to solid propellant combustion in rocket engine. Therefore, a successful prediction of the thermo-fluid mechanical characteristics development of gas and particles is very crucial and imperative for the successful design and operation of rocket nozzles and energy conversion systems. This paper describes an interaction phenomenon when a moving shock wave hits a two-phase medium of gas and particles with/without chemical reaction. A particle-laden gas is considered to be located along a ramp so that numerical integration is accomplished from the tip of ramp for a finite period. For the numerical solution, a fully conservative unsteady implicit second order time-accurate sub-iteration method and the second order Total Variation Diminishing scheme are used with the finite volume method for gas phase. For particle phase, the Monotonic Upstream Schemes for Conservation Laws as well as the solution of the Riemann problem for the particle motion equations is also used together with the schemes above. Transient development of thermo-fluid mechanical characteristics is calculated and discussed by changing the particle mass density and particle specific heat. For the case of the reacting particle-laden gas flow, a carbon particle-laden oxygen gas is considered to be located along a ramp. The results are discussed by comparison with the cases of the pure gas and the inert particle-laden gas. Major results reveal that when the particle mass density is smaller, there is a stronger interaction between two phases so that the velocity and temperature differences between two phases more rapidly decrease. When the particle specific heat is varied, only a thermal effect is observed while the other effects are minor. The case with reacting particles yields significantly different results due to chemical reaction such that the gas density does not monotonously but rapidly decrease due to the slip line in the relaxation zone, while the pressure and temperature become higher in comparison with the non-reacting case. But the dynamic variation would be only secondary to the thermal one. (C) 2003 Elsevier Ltd. All rights reserved.