Visualization of flames in combustion chamber of hybrid rocket engine with multi-section swirl injection method

In order to clarify combustion phenomena of hybrid rocket engines with multi-section swirl injection method, visualization tests of combustion flames has been conducted. In the present paper, paraffin fuel whose regression rate is high was used, and several types of placement of ports which inject oxygen into combustion chamber were compared. The number of the ports in each section had marginal effect on a combustion phenomenon. On the other hand the distance between each cross-section affected performance and combustion phenomena. In multi-section opposite injection method, the flow toward downstream of combustion chamber was observed. In both methods, enlarging the surface area that high temperature gas flows along was very important to increase regression rate.