A computational framework for predicting the combustion of energetic materials in an expanding chamber

Abstract

Purpose Various simplifications are introduced into the establishment of numerical models for problems with strong nonlinear interactions. The combustion of energetic materials in a chamber with moving boundaries is a typical example. This paper aims to establish a coupled numerical model for predicting the internal combustion in a launch process. Design/methodology/approach A two-fluid model is used to predict the fluid field induced by the propellant combustion. The moving boundary is located by using a finite element method. Based on a user subroutine interface in the commercial software ABAQUS, the development of the fluid field and the mechanical interactions is coupled with each other. Findings The paper is devoted to provide a coupled computational framework for predicting the propellant combustion in an expanding chamber. The coupling strategy is validated through predicting a pressure-driven piston system. Based on the validated computational framework, the two-phase reactive flows in a launch process is studied. The predicted parameters agree well with experimental measurements. Originality/value This paper provide a method to address the difficulties in realizing the dynamic interactions between multi-phase reactive flows and mechanical behaviors. The computational framework can be used as a research tool for investigating fluid field in a combustion chamber with moving boundaries.

A Godunov type method determining boundary conditions to predict the transient heat transfer in an expanding combustion chamber

“…The focus of the present work is to establish the message interactions between the combustion and the heat transfer. Similar with our previous work (Hu and Zhang, 2018a), the code used to predict the combustion of the energetic materials was programed in FORTRAN. Based on the approximated variable distributions in the reactive gases, the heat transfer coefficient was determined through a user subroutine interface VDFLUX in ABAQUS.…”

“…Therefore, the variation of the cross-sectional area should be considered in the governing equations. Related governing equations and the corresponding auxiliary equations can be obtained in our previous work (Hu and Zhang, 2018a). The partial differential equations are organized to form a hyperbolic system in conservative form, which are shown in equations (9)-(12): where W is a column vector that consists of conserved variables, F is the flux vector, and H is the source vector.…”

“…Transient heat transfer problems induced by moving heat sources (MHS) are the examples. The problems are easily encountered in engineering applications such as welding (Chakraborty, 2003; Amberg and Do-Quang, 2008; Shibahara and Atluri, 2011), cutting (Wildegger-Gaissmaier and Johnston, 1996; Zhou et al , 2013) and launching (Şentürk et al , 2016; Hu and Zhang, 2018a). Addition to systems with simple structures and simple boundary conditions (Talati and Jalalifar, 2009; Aderghal et al , 2011; Parkitny and Winczek, 2013; Flint et al , 2018; Veldman et al , 2018), analytical or semi-analytical solutions are difficult to be constructed for most of the MHS problems, especially for problems with heat sources comprised of combustion products.…”

“…According to the assumption, the density of the products is uniformly distributed in the combustion chamber and the velocity is linearly distributed along the axis of the barrel. According to multidimensional and multi-phase flow models (Wildegger-Gaissmaier and Johnston, 1996; Beckstead et al , 2007; Miura et al , 2008; Sung et al , 2013; Cheng and Zhang, 2014; Qiao and Zhang, 2017; Hu and Zhang, 2018a) for the combustion, the density, velocity and pressure of the combustion products are irregularly distributed in the chamber. Due to the high-pressure environments and the nonlinear mechanical interactions in the barrel, discontinuities such as flame waves and shock waves are unavoidable phenomena.…”

“…Different from the existing works, a Roe’s scheme was coupled with an explicit finite element method, which was used to predict the nonlinear mechanical interactions, to update the distribution of the expanding heat source. The coupling strategy was similar with the approach used in our previous works (Hu and Zhang, 2018a, 2018b). The mathematical models for the combustion and the heat conduction are given in Section 2.…”