Research On The Operating Characteristics Of Propellant Cross-feed System In Parallel Rocket

Propellant cross-feed technology is conducive to improve payload capability of liquid rocket launcher and the basic of engine-out ability.In order to get the properties of propellant cross-feed system and promote the application of cross-feed technology,a parallel rocket was researched by simulation and experiment.Dynamic models of propellant tank 、 pressurization components 、 transmission components and engine were developed,and simulation models of these components were developed based on AMESim.Scale test on cross-feed test platform with two boosters was carried on to test the simulation models to make sure the deviation is less than 5%.Ullage pressure difference、flow resistance and flight overload are the three key factors of cross-feed system.The influence law of these factors shows that propellant can be delivered from the booster to the core stage by ullage pressure difference,however the difference must be controlled precisely.The flow resistance of upstream piping and cross piping should be reduced because of great influence on the system.The influence of flight overload occurs later of complete period,which affects system performance with ullage pressure difference.Study focused on two kinds of schemes called pressure-base scheme and resistance-base scheme based on cross-feed test platform with two boosters and system simulation models.Flow characteristic、pressurizing characteristic、deviation adaptability and engine failure adaptability were understood,and control strategy of engine-out condition was put forward.The study shows that pressure-base scheme is very sensitive to ullage pressure difference,which should be controlled precisely with flight overload.There are two kinds of pressurizing schemes called self-pressurization and high-pressure tank pressurization,which can meet the demand for pressurization.The system has good fault adaptability because that the control strategy will regulating pressurized flow rate to regulating ullage pressure in order to adjust propellant flow rate in engine-out condition.Resistance-base scheme is very sensitive to performance and accuracy of the regulating valve with heavy caliber and short response time.During the switching process,core isolation valve must be opened before closing cross isolation.The system has good fault adaptability because that the control strategy will regulating flow resistance of pipeline in order to adjust propellant flow rate in engine-out condition.