Influence of Operating Pressure Upon the Weight of Liquid Propellant Rocket Motors for Medium Range Guided Missiles.

摘要

The propellant consumption of a rocket motor decreases as the combustion chamber expansion ratio increases and with a given back pressure the expansion ratio is proportional to combustion chamber pressure. Any increase in the latter involves an increase in the weight of certain motor components. Hence the reduction in consumption by increasing the operating pressure of the motor is to some extent off set by an increase in motor weight, and it is likely that an optimum pressure will be reached which gives a minimum all up weight of rocket motor and propellant for a given duty. In the past calculations have suggested that a chamber pressure of approximately 20 atm is the optimum. However, departures from this not infrequent as, for example, the V.2 which operated at 15 atm only and recent American designs which have chamber pressures of 50 atm. The actual optimum will be influenced by various factors such as the thrust level, time of operation, and the use of gas pressurized propellant tanks or turbo-pumps for delivering the propellant to the combustion chamber.