Numerical Study of a Microchannel Thermocycler with Sequential PCM Array for RNA Amplification

Numerical studies are performed for a microchannel embedded in three different phase changing material (PCM) encapsulations for achieving isothermal conditions required for denaturation, annealing, and extension phases in a sequential manner for thermocycling. PCM confinements for the denaturation and extension phases are preheated such that they transfer latent heat to the fluid passing through the microchannel. Whereas, the solid phase PCM kept in the annealing section absorbs latent heat of fusion from the fluid and thereby reduces its temperature congenial for annealing. Two-dimensional unsteady fluid flow and heat transfer in a microchannel with melting/solidification boundaries are solved using a finite volume solver based on SIMPLEC algorithm. A detailed parametric study is carried out by varying the size of the PCM storage and fluid flow rate (0.05 < Re < 1). Fluid temperatures in the microchannel and thermal performance aspects have been assessed for all the configurations. An accurate control over successive isothermal fluid conditions is found to attain. Hence the present configuration is a suitable candidate for miniature thermocycler configuration for RNA amplification.