燃料長さと形状スワール数がLT燃料を用いた酸化剤旋回流型ハイブリッドロケットの局所燃料後退速度に与える影響

抄録

In this study investigated that the effect of fuel length and geometric swirl number (S_g) on the local regression rate in swirling-oxidizer-flow-type hybrid rocket using a low-melting-point thermoplastic (LT) fuel. The LT fuel has excellent mechanical and adhesive properties, as well as a high regression rate compared to conventional hybrid rocket fuel. In the static firing test with logn fuel length, low values of averaged-regression rate are observed and these results show the different tendency of results from a previous study. It is considered that the effect of the oxidant swirling flow diminishes toward the fuel trailing edge and the average fuel retraction rate decreases. The equation of average regression rate of the LT fuel including S_g (0, 9.7, 19.4, 37.4) and fuel length was shown as r = 0.059S_g ^0.224G_p^0.788L_f^-0.166. The local regression rate at S_g = 9.7 and 19.4 increase the local regression rate behind the fuel compared to S_g = 0. Influence of the development of the turbulent boundary layer might be considered. At S_g = 9.7, the fuel residue amount is approximately 29.8% of S_g = 0. These results show that it is possible to realize a hybrid rocket engine with high fuel regression rate and low fuel residue by selecting the appropriate shape swirl number corresponding to the fuel length.