To design the preburner to provide uniform temperature, we use 3-D Computational Fluid Dynamics (CFD) to model the LNG and liquid oxygen combustion process. CFD predicts fluid behavior by solving the Navier-Stokes equations to describe how the velocity, pressure, temperature, and density of a moving fluid relate. CFD of reacting flows, especially those that also involve a phase change, is much, much harder because it must also solve chemistry along with state equations. Combusting CFD has only become practical with recent advances in chemical physics models and computing power.
To date, we’ve completed several million core hours of CFD modeling of BE-4 combustion processes. Modeling of the preburner shows good mixing and temperature uniformity upstream of the turbine. The combustion and temperature data we’ve gathered in our subscale testing correlate with our CFD predictions and show that our preburner sizing and injector element design meet design requirements. The ability to do combusting CFD simulations doesn’t eliminate the need for rigorous testing, but it will significantly shorten the test-fail-fix loop on the test stand. We’ll keep you updated.