Transient Analysis of Liquid Rocket Engine Chilldown and Startup by Conjugate Heat Transfer Approach

This study investigates the use of an in-house Conjugate Heat Transfer (CHT) numerical solver for the modelling of transient phenomena in liquid rocket engines active cooling systems. Heat transfer considerations place great limitations in the development of rocket engines and transient operative conditions are amongst the most critical. The current lack of models and numerical tools capable of accounting for the complexities of this time-dependent multi-physics problem, results in oversized cooling systems, long development times and increased risk of failure. The CHT solver proposed in this work utilizes a partitioned coupling strategy where two extensively validated single-physics solvers exchange information through their interfaces at discretized time steps. A simplified version of the RL-10A-3-3A regenerative cooling jacket is considered as a reference to test the strengths and the limits of this approach. In particular, both a complete chill-down of the engine and the start-up transient have been simulated. The analyses performed show the ability of the solver implemented to deal with transient phenomena where fluid-structure interaction occurs. In addition, they provide a complete overview of the numerical issues related to the partitioned coupling approach. These preliminary results pave the way for further developments aimed at increasing the reliability of the solutions and extending the domain of application of the software developed.