SIMULATION OF UNSTEADY LAMINAR FLOW IN MICROCHANNEL TUBES:INFLUENCE OF WALL MATERIALPROPERTIES ON FLUID–THERMAL PERFORMANCE

Abstract

Micro-scale thermal systems frequently employ microtubes whose wall material determines the thermal response under pulsatile operation. This study synthesizes representative results for three wall mate3rials (PDMS, stainless steel, silicon) across frequencies from 1 Hz to 1000 Hz to illustrate typical trends in hydraulic impedance, wall-shear dynamics, and conjugate heat-transfer behavior. High-conductivity walls suppress wall-temperature excursions and thermal lag; low-conductivity walls show larger apparent Nusselt numbers when referenced to wall-to-bulk temperature dif-ferences, despite inferior absolute thermal performance. The results highlight the role of wall properties in defining overall thermal–fluidic behavior in microchannels under unsteady operation.