Application Cases

Experiment Name: Droplet Ejection Method Based on Pulsed Airflow

Experiment Content:This technology primarily utilizes the control of the on-off state of the airflow channel to form periodic pulsed airflow. The pulsed airflow enters the droplet ejection device and acts on the liquid within the microchannel, generating a strong shear force on the liquid. Under the influence of the velocity and pressure of the pulsed airflow, the liquid is broken into droplets. During the droplet ejection process, the frequency, volume, and velocity of droplet ejection can be precisely controlled by indirectly regulating the air pressure, frequency, and duty cycle of the pulsed airflow.

Research Direction:Droplet Ejection

Testing Equipment:ATA-3080 Power Amplifier, Signal Generator, etc.

Experiment Process:

Compressed air flows from the air tank into the buffer tank, and the pulsed airflow pressure is controlled by a pressure valve. The liquid is injected into the droplet ejection chip by a syringe pump, while the flow rate of the fluid is controlled to generate droplets of different volumes. The pulsed airflow is driven by an electromagnetic valve, and the frequency and duty cycle of the pulsed airflow can be directly controlled by a signal generator and power amplifier to adjust the droplet ejection frequency and velocity. Due to the performance limitations of the electromagnetic valve itself, the maximum operating frequency is only 200 Hz. The droplet ejection process is observed and recorded using a high-speed camera, with a frame rate of around 20,000 fps selected according to the actual situation. The displacement of the droplets during the ejection process is measured using ImageJ, and the droplet ejection velocity can be calculated in combination with time.

Experiment Results:

The use of pulsed airflow to eject fluid has achieved precise control of high-frequency droplet ejection. By keeping the droplet ejection frequency consistent with the pulsed disturbance frequency, the volume of droplet ejection can be precisely controlled by regulating the fluid flow rate, and the velocity of droplet ejection can be controlled by adjusting the duty cycle. In summary, the volume, velocity, and frequency of droplet ejection can all be independently regulated, breaking through the limitations of existing droplet ejection technologies. This allows for more precise manipulation of droplet behavior. Moreover, by using pulsed airflow to shear the fluid, droplets with higher viscosity (＞200 mPa·s) can be formed at a lower air pressure, increasing the practicality and expandability of this technology and providing important technical support for the construction of droplet ejection platforms in various fields.

Power Amplifier Recommendation:ATA-3080C Power Amplifier

Figure: Specifications of the ATA-3080C Power Amplifier