Research On Rocket Solid Propellant Level Gauge Technology Based On Neutron Radiation

With the continuous development of aerospace and weaponry,solid propellant as a high-efficiency fuel is widely used in rockets,missiles and aircraft.In order to ensure combustion efficiency and safety performance,the propellant in the fuel bunker must be limited to a certain range,the solid propellant needs to be molded and poured in advance,and the solid propellant pouring material level is accurately monitored during the pouring process.Aiming at the actual problem of high-precision level measurement,we designed a solid propellant level monitoring program based on double collimation neutron radiation detection method,which can effectively improve the accuracy of level measurement and accuracy.This paper introduces the principle of interaction between neutron and matter,adopts double collimation radiation measurement method,uses MCNP simulation software to build rocket solid propellant pouring bin model,and conducts simulation calibration and optimization of material level measurement.Design of the rocket solid propellant digital coordinated control material level monitoring system,the hardware part mainly includes:pulsed neutron radiation data acquisition module and processing module,the acquisition module mainly includes BGO detector,photomultiplier tube,signal preprocessing and amplification circuit,processing module It is mainly composed of an A/D conversion circuit with AD9226 as the core and a main control circuit with FPGA+DSP as the core.The software part involves functions such as A/D sampling timing control,pulse signal data storage and display,and introduces the extended Kalman filtering algorithm.While estimating the predicted value of neutron radiation pulse,it is judged whether the parameter value of the system itself has changed.The neutron radiation pulse signal is estimated and corrected to automatically improve the filter design,reduce the actual error of the filter,and optimize and correct the neutron pulse data that produces deviations.Use Matlab-simulink tool to model the extended Kalman filtering algorithm.Simulation experiments and test results show that the neutron level gauge of the dualcollimation radiation detection method can be satisfied with the level monitoring of the solid rocket propellant fuel pouring.We can effectively estimate the non-linear signal by inputting 50 ns neutron radiation pulse after processing by the extended Kalman filter algorithm.The system error has been kept below 2%,which can meet the error index of the initial design of the system.