A continuous flow microfluidic calorimeter: 3-D numerical modeling with aqueous reactants.

Area of Science:

• Chemical Engineering
• Computational Fluid Dynamics
• Heat Transfer

Background:

• Microchannel reactors are increasingly used for chemical synthesis and analysis.
• Understanding heat and mass transfer is crucial for optimizing reactor performance.
• Accurate temperature measurement is essential for determining reaction energetics.

Purpose of the Study:

• To computationally analyze the reacting flow field, species diffusion, and heat transfer in a coflow microchannel reactor.
• To investigate the impact of thermal boundary layers and substrate material on temperature distribution.
• To assess the feasibility of using this configuration for microcalorimetry.

Main Methods:

• Utilized the Fluent computational fluid dynamics package to solve Navier-Stokes, mass transport, and energy equations.
• Incorporated an energy model including enthalpy of reaction as a non-uniform heat source.
• Validated the energy model through control volume energy balance calculations.

Main Results:

• Temperature was found to be nearly uniform across the channel thickness, normal to the substrate.
• Heat transfer was predominantly influenced by the glass substrate material.
• Numerical results indicate that surface temperature measurements are representative of the average temperature.

Conclusions:

• The microchannel reactor configuration exhibits favorable temperature uniformity for sensing applications.
• A microcalorimeter could be developed based on this design.
• Optical nanohole array sensors possess adequate spatial resolution for determining enthalpy of reaction.