Numerical investigation of aspect ratio effect on thermal parameters in laminar nanofluid flow in microchannel heat sink

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute. In this paper, laminar nanofluid flow of ethylene glycol-based of 4% volume fraction CuO(II) in a silicon rectangular microchannel heat sink with constant hydraulic diameter and different aspect ratios, with a constant heat flux, has been treated numerically. The effect of changing aspect ratios on the pressure loss and thermal parameters of the microchannel, such as Nusselt number(Nu), heat transfer coefficient(h) and non-dimensional temperature in fluid phase and solid(wall) phase have been investigated, using the finite volume method. In addition, the maximum and minimum values of thermal parameters and pressure loss have been calculated and the optimum aspect ratio for the performance of such systems has been evaluated.