Scale effects on hybrid rocket engine performance

In the current study, the effects of scaling up a hybrid rocket engine (HRE) in size has on its performance is investigated. A HRE design from a past RU study is selected as the base model to be progressively increased in size while geometric scale is maintained, up to ten times the original’s size. A computer program employing a quasi-steady convective heat feedback burn rate model is used to conduct simulated engine firings. One finding from this study is that the drop- off in performance for this engine, in going up in size, is not as much as expected. This can be attributed to a conservative oxidizer injection temperature setting in the model, and an oxidizer-fuel ratio mixture influence for this engine that is more impactful. The results presented here however do, to some degree, concur with established trends, with respect to thrust prediction, as the reference HRE is scaled up in size.