Flow Regulation Performance Analysis of Microfluidic Passive Valve for High Throughput Liquid Delivery

Area of Science:

• Microfluidics
• Mechanical Engineering
• Fluid Dynamics

Background:

• Microfluidic passive valves (MPVs) are critical components for precise flow control in microfluidic systems.
• The reliability of microfluidic systems is directly dependent on the performance of their flow control elements.
• Existing MPVs may face challenges in maintaining consistent flow rates under varying inlet pressures.

Purpose of the Study:

• To propose and characterize a novel microfluidic passive valve (MPV) capable of delivering a constant flow rate.
• To investigate the mechanism by which the MPV achieves flow rate stability.
• To analyze the flow characteristics of the MPV using numerical simulations.

Main Methods:

• Design and fabrication of a novel MPV utilizing fluid force and spring force for flow regulation.
• Experimental testing to evaluate flow rate stability under varied inlet pressures (1.25 kPa to 3.5 kPa).
• Numerical simulations to analyze internal flow dynamics, velocity profiles, and pressure drop regions.

Main Results:

• The novel MPV demonstrated a nearly constant flow rate of 6.26 mL/min with only a 6.5% variation across the tested pressure range.
• The valve automatically adjusts the gap channel size to maintain flow rate stability.
• Numerical simulations revealed increased maximum velocity and expanded pressure drop regions with rising inlet pressure.

Conclusions:

• The developed MPV offers a reliable solution for constant flow delivery in microfluidic applications.
• The design principle, based on balancing fluid and spring forces, effectively compensates for inlet pressure variations.
• This research provides valuable insights for designing high-throughput liquid delivery MPVs.