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Selected state of the art micro scale convective heat transfertechniques are presented for use in heat sinks and heat exchangers.Hereby focus is put on optimal design aspects for micro channel componentsand their effect on the over-all system performance in micro-electronicscooling applications. For direct liquid cooled heat sink applications,steady and unsteady single-phase flow operation are discussed andcompared with possible operating conditions for two-phase flow. Regardingcompact heat exchanger applications, the effects of downscaling arediscussed in terms of the penalties on hydraulic and thermal performance.Comparing the optimal design of heat sinks (minimal thermal resistanceand thermal gradients as well as maximal energy recovery) and heatexchangers (maximal power density), different criteria for flow conditionsand material properties emerge.

Genetic algorithms (GAs) are considered to be one of the main types of evolutionary algorithms (EAs) and are being increasingly used in various engineering design applications. To a large extent, plate-fin heatsinks are used in the thermal management of compact electronic equipment and data centers. The shape optimization of the heatsinks is not rigorously investigated during the design process of high power electronics. Any improvements in the effectiveness of the heatsinks impact the energy consumed by large-scale information communication technology (ICT) facilities including data centers and telecommunication systems and promote a more sustainable use of raw materials. This paper investigates the optimization of plate-fin heatsinks by modifying the fin layout in a forced crossflow using a multi-objective genetic algorithm (MOGA) combined with computational fluid dynamics (CFD) simulations. The main objective is to improve the heat dissipation rate by modifying geometric parameters, i.e., the number, arrangement, and orientation of fins. For a generic heatsink test case, the optimized performance is examined in terms of thermal resistance, turbulence intensity, pumping power, coefficient of performance, and Chilton–Colburn j-factors. Among all of the cases investigated, the input parameter optimization configurations which coupled and rotated fins in groups of ten proved to be the most successful. For one case, an 18% increase in the effectiveness of heat dissipation is reported. However, when weight reduction was considered by dividing by the unit mass, the designs in one of the investigated families which remove a number of fins from the heatsink outperformed the rest, achieving improvements of 65% over the baseline.

Tidal power can be described as harnessing the kinetic energy of the in and out flows known as tides created by the changing gravitational pull of the moon and the sun on the oceans of the world. As the relative positions of the sun and moon can be accurately predicted, so can the resultant tidal movements, making tidal energy such a valuable resource and an attractive option for renewable power generation. However, the high costs and difficulties associated with the deployment of underwater turbines, which includes anchoring, are prohibitive factors in the widespread utilisation of tidal power technology. Existing turbine fixation methods are primarily based on the use of large gravity anchors or monopole structures to secure the turbine to the seabed. In an effort to reduce size, environmental impact on the seafloor and installation cost, a hydrofoil-based anchor could be considered. The objective of this study is to experimentally test the lift and drag force behaviour of a finite-span hydrofoil with endplates, whose profile was selected based on simplified two-dimensional (2D) numerical simulations using the vortex panel method. A customised lift and drag force measurement system for this prototype hydrofoil was designed, fabricated and calibrated, and subsequently installed and tested in the Dutch Tidal Testing Centre (TTC) in Den Oever, the Netherlands. A series of tests with force and flow velocity measurements are described for different angles-of-attack under realistic tidal flow conditions. Results for the lift and drag coefficients as a function of angle-of-attack are compared to numerical simulation data and revealed that the real-world lift force is predicted well, whereas the drag force is underpredicted by the numerical predictions. These findings provide useful information for the design of anchoring systems based of hydrofoil profiles.