Optimization Design And Experimental Study Of Microfluidic Inertial Switch

With a certain type of grenade as the application background,the microfluidic inertial switch adopts a variety of microchannel structures to study the movement characteristics of droplets in the microchannel.The microfluidic inertial switch has the functions of bidirectional stability,delay response and reliable locking,which can realize the application of microfluidic inertial switch in the intelligent ammunition fuze system.The performance of the switch is studied by theoretical analysis,finite element simulation and experiment.According to the application background of the switch,the design index of the switch is clarified.Aiming at the delay response characteristics of the switch,the effect of microchannel structure size on delay time is analyzed by multiphase flow simulation.Based on the results of simulation samples,a Kriging model of snake-shaped micro-channel delay time with its structure size is established.The model realizes the accurate prediction of serpentine microchannel delay time with the prediction error less than 0.1ms.The fitness function is established based on the Kriging model,and the size of the microchannel is optimized by using the genetic particle swarm optimization algorithm.Finally,a prototype was made to verify the delay function of the delay microchannel.The response characteristics of the microdroplet to different acceleration loads in the microchannel is analyzed.The microfluidic inertial switch adopts a buffer structure,a connector structure and a capillary valve structure to adjust the motion state of the microdroplet,which realizes the bidirectional stability function.The finite element simulation results show that typical service drop load(amplitude 12000 g,pulse width 300 s)is applied in two sensitive directions of the switch,the separation of mercury droplet will not occur,and the mercury droplet can recover automatically after the load disappears.Under the action of recoil acceleration load(amplitude 20000 g,pulse width 4ms),the mercury droplets can be connected to the electrode stably.The experimental results are consistent with the simulation results,which show that the switch has reliable bidirectional stability function.The separation of trace mercury droplets in the experiment was studied,and the precise separation of nano-level mercury droplets was realized by centrifugal force driving the mercury droplets.In order to realize the integration and miniaturization of the switch,a microfluidic inertial switch with delay response is proposed to integrate bidirectional stable microchannel and latching microchannel structures.The simulation results show that the switch can be closed reliably under the coupled environment of recoil and centrifugal force,and the delay time can reach 12 ms.