Pressure Measurements During Droplet Generation In Microfluidic Chips

In recent years,microfluidic technology has attracted extensive attention because of its advantages of low sample consumption,high handling capacity,short mixing time and eliminating cross-contamination,and it has been rapidly developed in many fields such as chemical material synthesis,cell engineering and biological detection.Droplet generation is the basic operation of microfluidics,it is of great significance to study its related mechanisms.However,there is little research on microchannel pressure before,this paper will supplement the previous results and support to the later researches.In this paper,all experiments are performed at low Capillary number(Ca<0.01).And the variation of pressure in each microchannel(continuous phase,dispersed phase and outlet)are measured during droplet formation,After comparing the trend of the pressure changes under different input flow conditions,the two types of microchannels(T-junction and flow-focusing)are found to have the almost identical pressure result during droplet generation.And The average energy loss on the outlet is not fixed but dependent on the input flow.Furthermore,it is also confirms that the pressure fluctuation on the dispersed phase during droplet generation is stable and independent of the input flow.In addition,the effects of external pipeline vibration on droplet formation and pressure in each microchannel are also studied,which includes applying vibrations to different pipelines of the T-junction and the relationship between the maximum acceleration of the applied vibration and the pressure fluctuation in the flow-focusing microchannel under different vibration conditions.Then the pressure fluctuation model under external vibration is proposed and verified.