Abstract
To overcome defects of conventional hybrid rocket motors such as low combustion efficiency and low thrust level, the authors propose a new idea of design. The point of this idea is that the motor uses dry towel propellant, in which oxidizer gas flows the gap space in the fuel bed consisting of plastic fibers, tubes, or rods. Combustion experiments were carried out to clarify the basic mechanism of dry towel propellant combustion. As a basic sample of the propellant, the authors employed two types of cylindrical fibrous filters as a fuel in which gas oxygen is flowing. Ambient pressure was varied from atmospheric to more than 10 kgf/cm2G. As the results, the oxygen gas flow rate was found to have little influence on the burning rate. With one type of fuel samples, jump-up of the burning rate was observed in the pressure range of 5 to 6 kgf/cm2G, indicating the change of the combustion mechanism in this pressure range. With the other type of fuel samples, this jump-up was not observed. Up to now, the reason and controlling factor of this jump-up phenomenon are not clear. It is indispensable to clarify the basic mechanism of this jump-up phenomenon to realize the proposed idea.
