Abstract:
The introduction of MEMS heat exchanger has established a new era in the history of
heat transfer in micro scale systems. This study is based on an analysis conducted using
commercial finite element package. During the analysis different parameters such as
temperature of wall, fluid inlet velocity and other fluid properties have been used as input
parameters for solving the governing equations and boundary conditions. After solving
the problem in finite element method, outlet mean temperature has been obtained which
is then used for further calculation to evaluate heat transfer behaviour of fluids.
The aim of this simulation is to find a substitute of conventional working fluids used as
coolant for MEMS heat exchanger and also to evaluate performance of fluids for
different geometry. Usually water and air is more preferable as coolant for their low cost
and availability. But they have some disadvantages too such as dust in content, forming
rust in metal contact etc. So a second option is needed such that the conventional fluids
can be substituted. Freon II has shown the highest outlet mean temperature during the
study. Freon 113 and ammonia has also shown a good percentage of increment of heat
transfer when surface area is increased. Moreover in this analysis, emphasis is also given
on the effect of geometry on the performance of different fluids. It is apparent from this
work that rectangular surface heat exchanger shows highest outlet mean temperature as
well as heat transfer of fluids in comparison to other geometry. Therefore it may be
suggested that rectangular surface may be used instead of wavy surface as it is also easy
to manufacture.
This work is an extension of a tutorial which showed the calculation of outlet mean
temperature of water for wavy surface MEMS heat exchanger with pitch 0.95 mm. The
rest of the work done in this analysis is based on the need of evaluation of performance of
fluids as well as geometry. The overall results obtained from this work are quite
satisfactory. It is thought to be helpful for the researchers in this field.
