Variable-Mass Dynamics Implementation in Multi-Physics Environment for Reusable Launcher Simulations

Abstract

One of the driving challenges in launcher Guidance and Control (G&C) design is the strong coupling between different disciplines such as propulsion, aerodynamics, actuators, and structures, which all have a multi-physics nature. Enabling a more efficient and accurate modeling of these multi-disciplinary interactions through the use of a multi-physics modeling approach is believed to be beneficial in expediting the design process, reducing the conservatism in the assumptions used by G&C design and thereby improving the launcher performance. In particular, the accurate modeling of time-varying propellant mass dynamics is an essential component during preliminary design studies since it might have an impact on the dynamical simulations that in turn influence the assessment and evaluation of the launcher performance and trade-off designs across disciplines. This paper presents the implementation of variable-mass dynamics towards the preliminary design and development of a dedicated multi-physics simulator, termed R2M2 (Rapid Reusable Launcher Simulation via Multi-physics Modelling), for multi-actuated vertical take-off vertical landing (VTVL) launch vehicles. The paper first recapitulates previous investigations on variable mass dynamics from relevant literature, including specific descriptions of the dynamical effects during translational and rotational motion. It further addresses the implementation of these dynamical effects within a multi-physics modeling environment and shows the impact of variable-mass dynamical effects on the rotational motion. The model implementation and analysis of results is performed using simple yet representative models of different burn types of propellants or engines which are commonly found in launch vehicle configurations.