Model for fluid and mass transport in a recirculating microfluidic system

A computer-implemented method of calculating a condition within a microfluidic device with recirculation, the method comprising:

• receiving a first reservoir fluid volume,
• receiving a second reservoir fluid volume,
• receiving a first concentration, the first concentration being the concentration of a component in a first reservoir,
• receiving a second concentration, the second concentration being the concentration of the same component in a second reservoir,
• receiving a time-dependent imposed pressure difference between the first reservoir and the second reservoir,
• determining a hydraulic pressure difference, wherein the hydraulic pressure difference is based on a first volumetric height of fluid in the first reservoir and a second volumetric height of fluid in the second reservoir,
• determining an effective pressure difference between the first and second reservoirs, wherein the effective pressure difference is based on the imposed pressure difference and the hydraulic pressure difference,
• using the effective pressure difference, accounting for reactions occurring within the microfluidic device that deplete or increase the first and second concentrations of the component,
• determining a value of the condition within the microfluidic device, and
• controlling an experiment using the microfluidic device with recirculation based on the value of the condition within the microfluidic device.