Thermal–Mechanical FEM Analyses of a Liquid Rocket Engines Thrust Chamber

Abstract

The Italian Ministry of University and Research (MIUR) funded the HYPROB Program to develop regeneratively cooled liquid rocket engines. In this type of engine, liquid propellant oxygen–methane is used, allowing us to reach very good performances in terms of high vacuum specific impulse and high thrust-to-weight ratio. The present study focused on the HYPROB final ground demonstrator, which will be able to produce a 30 kN thrust in flight conditions. In order to achieve such a thrust level, very high chamber pressures (up to 50 bar) and consequently high thermal fluxes and gradients are expected inside the thrust chamber. Very complex and high-fidelity numerical FEM models were adopted here to accurately simulate the thermal–mechanical behavior of the thrust chamber cooling channels, accounting for plasticity, creep, and low-cycle fatigue (LCF) phenomena. The aim of the current work was to investigate the main failure phenomena that could occur during the thrust chamber’s service life. Results demonstrated that LCF is the main cause of failure. The corresponding number of loading cycles to failure were calculated accordingly.

Thermostructural Numerical Analysis of the Thrust Chamber of a Liquid Propellant Rocket Engine

“…Since the experimental testing activity for these applications can be very expensive, it is mandatory to minimize experiments by adopting high fidelity numerical models. Within this context, the accuracy of the numerical modelling obtained in a previous investigation by the authors [ 6 ] was improved thanks to the current investigation. Particularly, the main advances with respect to the aforementioned work were summarized here: A time step sensitivity analyses was conducted in order to better describe those phases where very steep temperature changes occur in very short time periods, i.e., during ignition and purging phases.…”

“…Then, several efforts have also been made to implement accurate viscoplastic models able to reproduce the actual deformation of the cooling channel [ 4 , 5 ]. The present paper is a continuation and improvement of a previous work [ 6 ] by the authors, whose aim was to analyze, from a numerical point of view, the main causes of failure of a liquid rocket engine thrust chamber.…”

“…Particularly, the main advances with respect to the aforementioned work were summarized here: A time step sensitivity analyses was conducted in order to better describe those phases where very steep temperature changes occur in very short time periods, i.e., during ignition and purging phases. A sub-modelling approach was implemented to transfer boundary conditions from a global coarse model to a local fine model (in [ 6 ], simplified boundary conditions were applied to the cut boundaries of the local model with no assessments for the global model). A relaxation phase was added after the purging phase in the thermomechanical loading cycle: during this phase, the thrust chamber slowly returns to environmental thermal conditions, with consequent relaxation of thermal stresses.…”

Starting and Regulating Characteristics of Electric Pump Feed System for LRE under Different Schemes

“…The effect of speed and mass flow on the actual working process is usually considered. The pressure head function of the centrifugal pump is obtained by the curve fitting method, as shown in Equation (1). The form of the dynamic equation of centrifugal pump torque is the same as that of pressure head.…”

“…Powerful propulsion sources are necessary for access to space, such as liquid rocket engines, ramjet engines, and their combinations [1][2][3][4]. The traditional propellant feed system of liquid rocket engines mainly includes a turbine pump cycle and pressure-fed system.…”