UCDS Based Stable Injector Design

History has repeatedly shown that combustion instability is the greatest technical risk faced in any chemical propulsion development program. The UCDS Process addresses this issue by using a rigorous physics-based analytical framework to decompose the complex flow field inside a chemical propulsion device, such as a liquid or solid rocket, in a way that allows rapid simulation of the dynamic behavior. Using UCDS it is possible to generate high fidelity predictions of the time evolution, amplitude and waveform of a pressure oscillation, along with any changes to the mean properties due to non-linear effects. Furthermore, it has been shown that the modal Alpha (linear growth rate) is a key physical parameter that defines the dynamic behavior of a rocket and provides a reliable measure of combustion stability margin.By monitoring how the array of modal Alphas change with design or operational features, the effects on engine combustion stability can be predicted. This insight provides the means to eliminate instability without resorting to expensive cut-and-try iterative developmental testing. GTL proposes to use this design guideline and the UCDS<SUP>TM</SUP>Process to create a clean-sheet design for a new liquid rocket that is inherently stable and compare it to an existing engine.