Optimising Impinging Microjet Arrays for Varying Heat Source Size in Liquid Cooled Coldplates

The increasing power density levels in integrated circuits has led to the development of thermal bottlenecks which limit the performance of electronic systems. This is due to the disparity that now exists between advanced electronics and the devices with which to cool them. This research seeks to develop an engineering solution using liquid jet arrays, which produce high convective heat transfer coefficients to target areas of concentrated heat flux. The multi-physics conjugate problem is to be addressed by developing new design methodologies leveraging both single and multi-objective optimisation processes to inform the thermal-fluids design of a convective heat exchanger, creating the opportunity to tailor the cooling system design to specific applications. A test facility was fabricated to verify the computational fluid dynamics model for different heat source sizes. This model was then configured to run optimisation parametric studies for a range of jet array configurations on the orifice plate, with the aim of determining the optimum orifice jet arrangement for a given heat source size. The simulation results indicated that when minimising both objective functions of source temperature and pumping power across the cooling manifold, the optimum designs favour relatively focussed arrays of highly populated jets with low jet-to-jet spacings. Alternatively, when only considering a single source temperature objective, more focussed arrays of lower jet population and flow rates with higher jet velocities and inter-jet spacing are favoured to achieve larger convective cooling intensities and higher overall source-to-sink heat transfer coefficients.