Patent ID: 6519554
Filing Date: 2003-02-11
Classification: G05B

Abstract:
A method for evaluating a gas generator launcher system including at least one gas generator having a gas generant fuel housed within a combustion chamber, a gas expansion tank containing a compressed gas communicating with said combustion chamber through an internal orifice, a plenum communicating with said compressed gas tank through an external orifice, said plenum including a device to be launched, said method comprising the steps of:fixing the system geometry and establishing initial conditions of said launcher system including, characteristics of said gas generant fuel, geometries of said tank, internal and external orifices and plenum chamber, an initial pressure within said tank and characteristics of said device to be launched including a gap existing between said device and walls of said plenum; modeling a gas generant fuel burn rate and calculating an amount of mass and energy added to the combustion chamber as the fuel generates gas; calculating a rate of mass flux out of said combustion chamber and into said gas expansion tank utilizing said internal orifice geometry, tank and combustion chamber temperatures, tank mass, and a ratio of combustion chamber and tank pressure; calculating a rate of energy flux out of said combustion chamber and into said expansion tank utilizing the rate of mass flux out of said combustion chamber and into said tank, the combustion chamber temperature and the specific heat of the generated gas; calculating a rate of mass flux out of said tank and into said plenum using external orifice geometry, tank and plenum temperatures, plenum mass and a ratio of tank and plenum pressures; calculating a rate of energy flux out of said tank and into said plenum using the rate of mass flux out of said tank and into said plenum, the tank temperature and the specific heat of the tank gas; and modeling the launch of the device within the plenum using characteristics of the device, the mass and energy input into the plenum and subtracting losses resulting from blow-by through the gap between the device and the plenum walls.