Heat Transfer Enhancement of Elastic Turbulence in Curved Microchannel

Abstract

Flow instabilities of generalized turbulence can prompt heat transfer enhancement in Newtonian fluids. In curved microchannel, viscoelastic fluid also leads to complex behavior even flow instabilities at very low Reynolds number (Re) conditions, and hereby the potential heat transfer enhancement. The primary purpose of this paper is to obtain the influence factors on heat transfer in virtue of viscoelastic instabilities. Microelectronics manufacturing technology was taken to fabricate the microchips of curvilinear microchannels. Platinum films were used as micro heater and temperature measurement sensor, which were embedded in the polydimethylsiloxane (PDMS) microchannel. In our experiments, the polymer solution flow with large enough elasticity becomes quite irregular; even gets into elastic turbulence compared with sucrose solution flow. With a lower thermal conductivity, the polymer solutions show higher heat transfer intensity than sucrose solutions. Heat transfer enhancement due to elastic turbulence in a curved is hereby identified. Furthermore, viscoelastic effects act to augment the heat transfer effect in terms of the convective heat transfer coefficient.