The Application of Computational Thermo-Fluid-Dynamics to the Simulation of Hybrid Rocket Internal Ballistics with Classical or Liquefying Fuels: A Review

Abstract

The computational fluid dynamics of hybrid rocket internal ballistics is becoming a key tool for reducing the engine operation uncertainties and development cost as well as for improving experimental data analysis. Nevertheless, its application still presents numerous challenges for the complexity of modeling the phenomena involved in the fuel consumption mechanism and its coupling with the chemically reacting flowfield. This paper presents a review of the computational thermo-fluid-dynamic models developed for the internal ballistics of hybrid rockets burning gaseous oxygen with classical polymeric or paraffin-based fuels, with a special focus on the interaction between the fluid and the solid fuel surface. With the purpose of predicting the local fuel regression rate, which is the main parameter needed for the hybrid rocket design, the model is coupled with an improved gas/surface interface treatment based on local mass, energy and mean mixture-fraction balances, combined to either a pyrolysis-rate equation in the case of classical polymers, or to an additional equation for the liquid paraffin entrainment fraction of the total fuel consumption rate. A number of experimental test cases obtained from the static firing of two different laboratory-scale rockets are simulated to determine the models’ capabilities, showing very good agreement between the calculated and measured fuel regression rates with both standard pyrolyzing and liquefying fuels. The prediction of the chamber pressure measured with paraffin fuel resulted in it being more cumbersome for the single-phase flow assumption. The advantages and limitations of the models are discussed.

Modeling and CFD Simulation of Regression Rate in Hybrid Rocket Motors

“…Moreover, fuel pyrolysis and heterogeneous reactions at the nozzle wall were included via finite-rate Arrhenius kinetics. Several other authors have developed similar numerical tools [32][33][34][35][36][37][38].…”

An Investigation towards Coupling Molecular Dynamics with Computational Fluid Dynamics for Modelling Polymer Pyrolysis

“…The authors highlighted that a more detailed pyrolysis breakdown of gas products from thermal decomposition could improve the accuracy of smoke and Carbon Monoxide predictions. CFD modelling of polymer pyrolysis is also extensively applied in hybrid rocket engines [ 21 ]. Tyurenkova et al [ 22 , 23 , 24 , 25 ] conducted a comprehensive series of numerical studies on solid fuel pyrolysis in hybrid rocket engines and investigated the regression behaviour in different flow regimes.…”

Dynamic Numerical Simulation of Hybrid Rocket Motor with HTPB-Based Fuel with 58% Aluminum Additives

“…Typical hybrid rocket motors (HRMs) propellants consist of solid fuel and liquid oxidizers [1][2][3][4]. Since the propellants are stored in different phases, respectively, the hybrid rocket motor has obvious advantages compared with solid and liquid rocket motors in terms of simple structure, adjustable thrust, high safety, low cost, and multiple restart capabilities [5][6][7][8].…”