Thermal buffering performance of passive phase change material micro-pillar array systems on temperature regulation of microfluidic chips

Abstract

The microfluidic chip is supposed as an attractive strategy obtaining widely application potentials, while it generally suffers from acute temperature fluctuation owing to external force field, flowing resistance or chemical reaction. A passive phase change material (PCM) micro-pillar array module is novelty designed to deal with the temperature fluctuation of working fluid utilized in microfluidic chips. PCM enables to store or release thermal energy trough solid-liquid phase transition to guarantee suitable temperature of working fluid passing through the PCM micro-array module. Numerical model is constructed based on enthalpy-porosity and local thermal non-equilibrium theory between PCM and fluid. Results indicate that peak temperature of fluid decreases, whereas valley temperature of fluid increases with the elapse of time. Temperature difference between inlet and outlet fluids tends to be steady under leveling effect of the PCM micro-array module. Semi-sinusoidal fluctuation of fluid inlet temperature also contributes to periodic variation of thermal energy storage rate and liquid fraction of PCM. PCM, configurational, dimensional and operational parameters of the PCM micro-array module are evaluated and it is revealed that system performance can be substantially affected by these parameters. Thermal buffering performance indicates that temperature of outlet fluid can be moderated with more buffering effect on shifting valley temperature over shaving peak temperature. In conclusion, the built PCM micro-array module is beneficial to passively regulate and control thermal performance of microfluidic chips.