Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.
This work presents a three-dimensional geometric
optimisation of conjugate cooling channels in forced
convection with internal heat generation within the solid for an
array of circular cooling channels with different flow
orientations based on constructal theory. Three flow
orientations were studied: Firstly, an array of channels with
parallel flow; secondly, an array of channels in which flow of
the every second row is in a counter direction to one another
and thirdly, with the every flow in the array of channels in
counter direction to one another.
The geometric configurations and the flow orientations were
optimised in such a way that the peak temperature was
minimised subject to the constraint of fixed global volume of
solid material. The cooling fluid was driven through the
channels by the pressure difference across the channel.
The system had hydraulic diameter and channel to channel
spacing as degrees of freedom of the design variables. A
gradient-based optimisation algorithm was applied to search for
the best optimal geometric configurations that improve thermal
performance by minimising thermal resistance for a wide range
of dimensionless pressure differences. This optimiser
adequately handles the numerical objective function obtained
from numerical simulations.
The effect of porosities, applied pressure difference, flow
orientation and heat generation rate on the optimal hydraulic
diameter and channel to channel spacing were reported. Results
obtained show that the effects of dimensionless pressure drop
on minimum thermal resistance were consistent with those
obtained in the open literature.