Numerical Investigations of the Effect of Flow Arrangement and Number of Layers on the Performance of Multi-Layer Microchannel Heat Sinks

Abstract

With the advance of miniaturization technology, more and more electronic components are placed onto small electronic chips. This leads to the generation of high amounts of thermal energy that should be removed for the safe operation of these electronic components. Microchannel heat sinks, where electronic chips are liquid cooled instead of the conventional air cooling techniques, were proposed as a means to improve cooling rates. Later on, double layer micro channel heat sinks were suggested as an upgrade to single layer microchannel heat sinks with a better thermal performance. In the present study the effects of increasing the number of layers of the microchannel heat sink to three-layers as well as the effect of changing the flow arrangements (counter and parallel flows) within the three channel layers on the thermal performance of the heat sink were investigated. In all investigated cases the temperature distribution over the base of the microchannel heat sink system and the total pressure drop are reported. A range of mass flow rates from 1×10−4 to 5×10−4 kg/s was considered. Uniform heat flux conditions were considered during the study. COMSOL Multiphysics finite element package was employed for the numerical analysis. Results indicate significant enhancement in the uniformity of the temperature on the processor surface when multi-layer channels were employed, compared to the single-layer case. The uniformity in the temperature distribution was accompanied by reduction of pressure drop across channels for the same mass flow rate and heat flux conditions. The counter flow arrangement showed the best temperature distribution with the uniform heat flux cases.

Experimental Investigation of the Effect of Number of Layers and Flow Arrangement on the Performance of a Microchannel Heat Sink System

“…At low flow rates, counter-flow arrangement showed better uniformity in temperature distribution along the top microchannel layer because, unlike parallel flow arrangement, cold liquid is introduced to the MCHS from both sides. Such experimental results agree well with the numerical results mentioned by Effat et al [12]. As expected, cross-flow arrangement showed intermediate temperature uniformity between counter-and parallel-flow arrangements.…”

“…For example, counter-flow arrangement gave the lowest pressure drop because it exhibits high temperature, and thus lower viscosity, for longest length of the microchannel compared to parallel-and cross-flow cases as discussed in the next section. The numerical findings of Effat et al [12], supports the present ones as they stated that the pressure drop associated with counter flow arrangement is lower than that of parallel flow as well.…”

“…They tried to optimize the dimensions of the multi-layered microchannel in terms of the channel hydraulic diameter, channel aspect ratio, solid volume fraction, for the fixed solid volume that minimized the peak temperature and maximized the thermal conductance. Effat et al [12] in a similar study to that of Adewumi et al investigated the effect of flow arrangement and number of layers on the thermal performance of a multi-layer MCHS. They considered a number of layers of up to three and parallel and counter flow arrangements were considered.…”