Research On Key Technology Of Microfluidic Delay Inertial Switch

Integrated electronic S&A system is the development trend of fuse safety system.Micro inertial switch is used to detect the inertial environment and arm the fuse timely,which is an important component of the fuse electronic S&A system.This paper bases on the howitzer fuse electronic S&A system and focuses on the research of microfluidic delay inertial switch.Combine theoretical analysis,numerical simulation and experimental methods to research on microfluidic flow control,micro-channel structure design and other key theories and techniques of microfluidic inertial switch.And finally it realizes multi-functional integration of switch microchannel structure.The main contents are as follows.(1)The paper analyses the application environment and design requirements of microfluidic delay inertial switch to ensure its functional requirements and working modes.Since the working liquid flows in the microchannel in form of a whole micro-liquid column,a transient flow model was established based on the unsteady Bernoulli equation,combined with the significant viscous effect and capillary phenomenon in micro-scale.The model was tested and verified by the transient flow simulation of micro liquid column and the transient flow experiment of microchannel prototype.The model can well describe the micro liquid column flow in microchannel under the action of inertial force.(2)The flow of micro liquid column is controlled by the damping feature of microchannel.The damping feature of microchannel is influenced by its structure parameters.By using multilayer feedforward artificial neural network to fit the function relationship between the structure parameters and the damping feature coefficient of microchannel,the damping feature model of microchannel was established.To increase the training efficiency of the model,PSE-BP algorithm was developed.Due to the combinatorial swarm optimization of gradient descent method,particle swarm optimization algorithm and genetic algorithm,and combined with BP algorithm.The algorithm can improve the training efficiency of microchannel damping feature model for more than 20 times.An automatic simulation framework,called pySim,was developed to enhance the acquisition efficiency of microchannel damping feature samples.The framework was programmed in Python,in view of the second development of simulation software through their script interfaces.(3)The damping features of rectangular straight microchannel and serpentine microchannel were theoretical analyzed and extracted.The pressure drop in straight microchannel is linear.Its damping feature coefficient is constant.The pressure drop in serpentine microchannel is periodically.The damping feature coefficient of serpentine microchannel can be still treated as constant due to the smaller pressure drop pulsation amplitude.The damping feature coefficient of serpentine microchannel is larger than that of straight microchannel,which can better realize the delay function of the microfluidic delay inertial switch.(4)Combined U-shape micro communicating vessel and capillary valve,the paper comes out communicator type acceleration loads distinguish microchannel with stronger anti-high overload capacity.By distinguishing between service drop and recoil acceleration load,a distinction between service handling and normal launch environment is achieved.The influence of the characteristic parameters of micro-channel structure and the material parameters of the working fluid on their environmental discrimination ability is analyzed.The structural characteristics of microchannel are optimized to expand the environmental adaptability and the reliability of environmental discrimination.(5)The microfluidic delay inertial switch is developed based on the combination of communicating vessel acceleration distinguish microchannel,snake delay microchannel,U shape latching microchannel.Photoelectric electrode is adopted to detect the motion of colored working fluid.The feasibility of the switch structure is verified.The switch realizes the function of distinction between service handling and normal launch environment,delay arming after muzzle,latching and strong ability of resisting high overload,with the characteristics of small size and good reliability.