Large scale three-dimensional topology optimisation of heat sinks cooled by natural convection

TL;DR

This paper applies density-based topology optimisation to 3D heat sink design cooled by natural convection, solving complex multiphysics equations efficiently for large-scale problems with millions of degrees of freedom.

Contribution

It introduces a scalable, parallel framework for 3D topology optimisation of heat sinks with natural convection, revealing new design trends at high Grashof numbers.

Findings

Optimised designs show increased branching with higher Grashof numbers.

The method handles large-scale problems with up to 330 million degrees of freedom.

Designs adapt to flow conditions, demonstrating the influence of natural convection.

Abstract

This work presents the application of density-based topology optimisation to the design of three-dimensional heat sinks cooled by natural convection. The governing equations are the steady-state incompressible Navier-Stokes equations coupled to the thermal convection-diffusion equation through the Bousinessq approximation. The fully coupled non-linear multiphysics system is solved using stabilised trilinear equal-order finite elements in a parallel framework allowing for the optimisation of large scale problems with order of 40-330 million state degrees of freedom. The flow is assumed to be laminar and several optimised designs are presented for Grashof numbers between $10^3$ and $10^6$. Interestingly, it is observed that the number of branches in the optimised design increases with increasing Grashof numbers, which is opposite to two-dimensional optimised designs.