Multiphase and Chemically Reactive Flows in LS-DYNA

We have developed a transient multiphase fluid dynamics and chemically reactive flow simulation capability in conjunction with the existing LS-DYNA FEM structure solver, which is a well-known general-purpose highly nonlinear, transient dynamic finite element software capable of simulating complex real world problems, and is widely used in automobile, aerospace, construction, manufacturing, and bioengineering industries. One of the solvers added to LS-DYNA is a compressible flow solver that employs the conservation element/solution element (CESE) method. To this CESE solver we have coupled a stochastic PDE solver for modeling sprays, as well as several chemistry solvers. The particles forming the sprays are tracked in a Lagrangian fashion, such that the multiphase interfaces are treated as moving liquid phases. Through the coupling to the CESE solver, the essential features of compressible flow between the phases are captured. In the case of reacting flows with a large number of species, the computational singular perturbation (CSP) and the Gscheme reduced kinetics modeling without any tabulation are also developed. With experimental validations for the spray and chemically reactive flows, the LS-DYNA multiphase solver is demonstrated to be highly accurate and robust.