This paper presents a numerical simulation of flow in a microchannel heat sink. The channel
was defined as a dimension with less than 1.0milimeter and greater than 100.0micrometer. The ANSYS
CFX 2015 was used to predict the flow in the microchannel. Besides, simulations were undertaken to
determine the flow of the fluid within the microchannel in three different models. Therefore, three
different models were employed for this study. The first model was a square-shaped channel with 0.5mm
width and 0.5mm height constructed along 28.0mm channel length. The second and the third models
were in rectangular shape. The differences between these models were their width and height of
channel. The dimension for the second model was 0.75mm height and 0.5mm width (rectangular A),
while the dimension for the third model was 0.5mm height and 0.75mm width (rectangular B). All the
microchannel heat sink models had been simulated and showed results for pressure, temperature, and
velocity inside the microchannel. The results were compared for each model and the data had been
validated from published data. In addition, the initial velocity was set in a range between 0.1m/s and
0.5m/s. The highest pressure drop was recorded for the square microchannel. It was 58.12% higher
than the pressure drop found in the rectangular microchannel with 0.75mm width, while 0.02% closer
with the 0.75mm-height rectangular microchannel. Furthermore, there was a 33.34% of temperature
difference, which had been higher for the square microchannel. Nevertheless, the highest velocity of
0.57m/s was recorded at the outlet of the microchannel. These had been consistent with other published
data.