A Multifidelity Simulation Method for Internal and External Flow of a Hypersonic Airbreathing Propulsion System

Abstract

As hypersonic vehicles are highly integrated, a multifidelity simulation method based on a commercial solver is developed to reduce simulation time for such vehicles and their propulsion systems. This method is characterized by high-level fidelity numerical analysis of external flow and low-level fidelity numerical analysis of internal flow. The external flow of a propulsion system is solved by RANS equations. The internal flow is modeled by a quasi-one-dimensional equation. The interaction between external and internal flow is governed by a CFD solver through a user-defined function (UDF). The static pressure distribution acquired from the multifidelity simulation method is in agreement with the experimental data, indicating that this simulation method can be used to study the flow physics of hypersonic propulsion systems at a reasonable cost. From a design perspective, the results indicate that the horizontal force increases with the fuel equivalence ratio, and the thrust balance is realized at φ = 0.35. The positive net thrust is maintained throughout the flight regime from Ma 4 to Ma 7, whether the combustor operates in ramjet or scramjet mode.