Modeling radiative heating of liquids in microchip reaction chambers

Abstract

Deterministic design of a microfluidic system that utilizes radiative heating requires accurate thermal modeling. Current modeling methods are limited to describing a subset of the spatial and spectral parameter space and thus cannot be extended to the full range of microchip platforms. This paper presents a broadly applicable approach to modeling the thermal response of liquid undergoing radiative heating in microchip reaction chambers by using optical and material properties for analytical and finite element methods. The fidelity of the model is demonstrated with experimental validation for two types of microchips, glass and plastic, and two types of radiative sources, blackbody and monochromatic, revealing root mean square deviations between 1.37 °C and 3.14 °C. By providing an understanding of how a radiative source interacts with a particular device and the resulting transient and steady state behavior, this modeling process can enable designs that maximize the efficiency and cost-effectiveness of a microfluidic heating system. These generalized models are expected to apply to any source, materials, and geometry for which the optical and material properties are known.