  With the increasing power density of electronics components, the heat
dissipation capacity of heat sinks gradually becomes a bottleneck. Many
structural optimization methods, including topology optimization, have been
widely used for heat sinks. Due to its high design freedom, topology
optimization is suggested for the design of heat sinks using a transient
pseudo-3D thermofluid model to acquire better instantaneous thermal
performance. The pseudo-3D model is designed to reduce the computational cost
and maintain an acceptable accuracy. The model relies on an artificial heat
convection coefficient to couple two layers and establish the approximate
relationship with the corresponding 3D model. In the model, a constant pressure
drop and heat generation rate are treated. The material distribution is
optimized to reduce the average temperature of the base plate at the prescribed
terminal time. Furthermore, to reduce the intermediate density regions during
the density-based topology optimization procedure, a detailed analysis of
interpolation functions is made and the penalty factors are chosen on this
basis. Finally, considering the engineering application of the model, a
practical model with more powerful cooling medium and higher inlet pressure is
built. The optimized design shows a better instantaneous thermal performance
and provides 66.7% of the pumping power reduction compared with reference
design.
