Design For Multi-channel Droplet Generation System

Microfluidic technology based on small volume,multiple types of sample detection has become a development trend,providing a great prospect for high-throughput experiments.The objective of this study is to design a micro droplet generating chip and a multi-channel micro droplet generating device,respectively,to realize rapid,uniform and stable droplet generation.The droplet diameter can be adjusted in the range of 90～120μm.The droplet generation rate of 20μL sample is about 20000～50000,the droplet generation rate is up to 1500 Hz,and the droplet spacing is about 0.3mm.The main research contents and results of this paper are as follows:1)The research status and development prospect of microfluidic chip at home and abroad,as well as the application and development of microfluidic technology are introduced,which provides theoretical guidance for the model simulation of software and theoretical basis for the droplet generation experiment.2)For micro channel the flow of the fluid in the theory and formula of calculation and COMSOL simulation involves in detail,including the basic principles of two-phase flow,the micro channel flow parameter calculation,finite element analysis method and level set theory,etc.,for the back of the design and simulation of microfluidic chip structure and the design of the droplet generation device,providing theory basis.3)Using COMSOL simulation software to simulate the droplet generation process,several influence factors of droplet formation is discussed,including the micro channel width depth ratio,flow rate of the two-phase flow,micro channel structure of the diameter of the droplet size,frequency,etc.and determine the corresponding index of chips,according to the results of the simulation design of droplet generation chip geometry structure,make the chip produces droplets meet the demand of experiment.4)According to the principle and characteristics of the droplet generating device,the overall design scheme of the droplet generating device is determined,and the hardware and software design of the multi-channel emulsion droplet generating device is completed.The device mainly includes power supply module,microprocessor module,pressure output control module,pressure generating module,etc.5)The relationship between the frictional resistance received by the microfluidic in the micro channel structure and the flow process was studied.Combined with the basic principle of two-phase flow,the pressure required by the micro droplet transport channel and vertical oil transport channel was calculated.Then,the experiments of droplet generation were carried out through the designed microfluidic chip,and the influences of two-phase flow velocity and micro channel structure on droplet generation were summarized and summarized,which basically matched the simulation results.Above study to multiphase fluid dynamics behavior law and regulation mechanism as the foundation,by using the method of simulation model combined with practice,systematically introduces and verify the design of microfluidic chip and the process of the microspheres preparation for the future in the field of biological engineering,droplet generation and microfluidic process of thinking and technical reference for the control and optimization.