In the present study, laminar flow and heat transfer of nanofluid water/single-wall carbon nanotubes have been investigated in a novel design of double layered microchannel heat sink (MCHS). Present investigation has studied the dimensionless values of truncated lengths (lambda) of 0, 0.4, 0.8 and 1. Studied Reynolds numbers were 500, 1000 and 2000. The effect of volume fraction of nanoparticles in the Newtonian suspension of water based nanofluid was studied for values of 0, 0.04 and 0.08. The results showed that the thermal resistance and ratio of maximum and minimum temperature difference for bottom wall of microchannel as well as the ratio of thermal resistance decrease by increasing the nanoparticles volume fraction and decrement of lambda. The Performance evaluation criteria (PEC) factor on the bottom of channel increases in all ratios of lambda, by augmenting volume fraction of nanoparticles. (C) 2017 Elsevier Ltd. All rights reserved.