Design And Experimental Research Of Microfluidic Inertial Delay Switch

In order to meet the design requirements of miniaturization in the fuze power safety system,a delaying-time microfluidic inertial safety switch is designed with a large and medium-sized grenade as a research background.The switch has the ability to identify service drop acceleration load and launching recoil acceleration load,out of the muzzle delay for more than 10 ms and reliable closure.The theoretical analysis,numerical simulation and experimental test methods are used to study the environment identification microfluidic inertial switch,the delaying-time microchannel flow characteristics and the delaying-time microfluidic inertial safety switch.The research of microfluidic inertial switch at high g value is broadened.The environmental force of the switch in the fuze is analyzed,and the design specifications of the switch are clarified.An environment identification microfluidic inertial switch is designed for the distinction between service drop acceleration load and launching recoil acceleration load.The switch is mainly composed of a circular microchannel and a three-stage capillary valve,which has the ability to identify two typical accelerations and can be reliably connected under the action of the normal launching recoil acceleration.The working principle of the switch is analyzed.Then,the prototype was fabricated by wet etching and magnetron sputtering.The function of the switch is verified by finite element simulation and prototype experiment.The experimental results show that the switch remains disconnected under the service drop load of 12800g/219μs.The static threshold of the switch is 3257.2～3317.3g.The pressure loss of mercury flowing in square curved microchannel,serpentine curved microchannel and sawtooth curved microchannel is investigated.Numerical simulation is used to analyze the influence of structural size parameters of three different shapes of microchannels on pressure loss.The serpentine curved microchannel is selected as the delay microchannel,and a prototype is fabricated.The centrifugal experiment results show that the delay time of serpentine curved microchannel is 15685μs.Based on the environment identification microfluidic inertial switch and serpentine curved microchannel,combined with the latching microchannel and the diamond transition microchannel,a delaying-time microfluidic inertial safety switch is proposed.The performance of the switch is verified by numerical simulation and experimental test.The switch is always disconnected under the service drop acceleration load.The switch is reliably closed under the coupling of the recoil acceleration load and the centrifugal acceleration load.Centrifugal experiments show that the delay response time of the switch is 16385μs.