Human Space Flight

Inside the Fire: Simulating Rocket Engine Combustion of Methane-Oxygen Fuel

Image from simulation of rocket combustion chamber showing the gas temperature of burning methane and oxygen, with colors ranging from blue and green through gold and red
Section view through the rocket combustion chamber showing the gas temperature of burning methane and oxygen. Blue contours indicate cold temperature while red contours are the hottest regions of gas. The 3D isosurface shows the injection of the methane and oxygen and the initial reactions, which occur at relatively low temperature. Brian Richardson, NASA/Marshall

As NASA develops vehicles to take humans to the Moon, Mars, and beyond, new engine systems are needed to guide these spacecraft to their destinations. While hydrogen fuel was used in the Apollo-era lunar landing missions, methane fuel has become a popular choice for in-space propulsion as it allows for smaller storage tanks. However, methane and oxygen-powered engines are a relatively new technology that requires analysis tools capable of predicting their performance and in-flight behavior, so researchers at NASA’s Marshall Space Flight Center are using the computational fluid dynamics (CFD) tool Loci-STREAM to model the complex, combusting flow inside various engine design concepts. They performed their CFD simulations on the Aitken supercomputer at the NASA Advanced Supercomputing (NAS) facility, with the goal of providing critical engine performance metrics to guide the complex rocket engine design process.

Quick Facts

Access to growing NASA supercomputing resources enabled combusting flow CFD simulations on a large scale and with geometric complexity that was thought to be infeasible just a few years ago. NAS support staff and the ability to reserve resources ensured that the simulations continued to proceed, allowing us to meet our schedule requirements.

Brian Richardson,
NASA Marshall Space Flight Center
  • The team conducted CFD simulations of reacting flow inside oxygen-methane spacecraft engine design concepts using the Loci-STREAM code, and required about 9.6 million processor hours over of period of 2.5 months on the Aitken supercomputer’s AMD Rome node architecture.
  • Loci-STREAM utilizes a compressible thickened-flame flamelet model, which was found to significantly reduce computational resources, compared to a traditional finite-rate chemistry model approach. The flamelet model approach reduces the number of equations in the CFD simulation by an order of magnitude and significantly reduces the time required to obtain a solution. The flamelet model approach combined with HECC computational resources enabled efficient modeling of an engine with hundreds of injector elements.
  • The analysis of the simulation results will be used to make design recommendations for future engine hardware development.
  • A combustion stability model is being developed using flame response functions extracted from the detailed CFD solution field, and future Loci-STREAM model improvements will enable simulations of time-varying engine start-up and shutdown operations.

Researcher

  • Brian Richardson, NASA Marshall Space Flight Center