Trial Design of Oxygen Feed System in A Small Ballistic Hybrid Rocket for Experimental Mission and Some Problems

摘要

As the one candidate of some low cost rockets for experimental mission, the hybrid rocket is considered very low cost system. The hybrid rocket uses the solid propellant and liquid propellant. Because of this, the production cost of the solid propellant is lowered. Also, as the advantage of the hybrid rocket, the engine performance and thrust becomes possible to vary by cahnging the the liquid propellant flowate. By using this function, the hybrid rocket can be used as a reusable rocket. And when the hybrid rocket system is considered to be reusable, then the system can provide a lower cost system. We study this reusable hybrid rocket as the small size rocket for observation mission. We are aiming at the observation rocket of a low cost more instead of TR-1A, small solid propellant rocket. In general, the hybrid rocket system is considered as simpler configuration and smaller dimension than the typical liquid or solid rocket system. We thought that decreases the development item and use the component of established. So, a small ballistic hybrid rocket for experimental mission may be able to be handled even by some young engineers or graduated students. We thought the most high cost and the key point compoent for the hybrid rocket were the liquid propellant feed system. There are the gas pressure system and pump feed system. We examined and compared with each systems. We added examination about the turbopump that is used in the pump feed system, selected as a result, and is the major component of this system. We tried the outline design of the turbopump for hybrid rocket in this paper. Because a low cost is demanded even the turbopump, we tried to design outline, whether or not the liquid oxygen turbopump (LTP) of the LE-5B engine is able to use it. As the result, some problems were cleared. And we considered that LE-5B LTP is not able to use as it is for this hybrid rocket engine's required specifications. (See Table.1 These specification are same almost with the TR-1A rocket.)