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The present work shows a study developed of the thermal and hydrodynamic behaviors present in microchannel heat sinks formed by non-conventional arrangements. These arrangements are based on patterns that nature presents. There are two postulates that model natural forms in a mathematical way: the Allometric Law and the Biomimetic Tendency. Both theories have been applied in the last few years in different fields of science and technology. Using both theories, six models were analyzed (there are three cases proposed and both theories are applied to each case). Microchannel heat sinks with split channels are obtained as a result of applying these theories. Water is the cooling fluid of the system. The inlet hydraulic diameter is kept in each model in order to have a reference for comparison. The Reynolds number inside the heat sink remains below the transition Reynolds number value published by several researchers for this channel dimensions. The inlet Reynolds number of the fluid at the channel inlet is the same for each model. A heat flux is supplied to the bottom wall of the heat sink. The magnitude of this heat flux is 150 W/cm2. The temperature fields and velocity profiles are obtained for each case and compared.

A parametric study was conducted in order to reduce the pressure drop and to improve the uniformity of flow distribution in a symmetric flow distributor. A CFD model was employed to simulate the flow behavior by solving the Navier-Stokes equations in a complete 3D model. The present work is a complete parametric study of a base model, reported in previous studies, but keeping the same flow pattern. To improve the performance of the base design, three known successive parametric ratios, as functions of the hydraulic diameters of the channels, were tested in order to study the advantages and disadvantages of each one in terms of two dimensionless parameters that measure the uniformity of flow distribution. A remarkable improvement in the performance of the base model was achieved by modifying the width ratio of the channels. The present work is a contribution to the study of flow distributors to be used as heat exchangers, PEMFC flow channels and other flow devices.

A numerical analysis of a gas turbine first stage bucket with internal cooling (model MS7001E) is presented. The internal cooling system consists of 13 cylindrical channels with turbulent promoters (ribs), which are implemented in order to achieve temperature decrements inside the body blade. Three different geometrics (square, triangular and semi-circular cross-section) are studied. Each configuration is analyzed having full or half ribs. These are placed inside the cooling channels. The effects generated by the aspect ratio variation between rib pitch and rib height (P/e), for a constant aspect ratio given by ribs height and hydraulic diameter (e/Dh) are considered. The numerical simulation was developed using finite volume method, by means of commercial software based on computational fluid dynamics (CFD). Each one of the models generated for each study case was built in a 3D model, including the platform and airfoil of the blade. The models consider the effects generated by the hot combustion gases are flowing around the blade and the coolant flow is flowing inside the cooling channels. The study includes the solution of the conjugate heat transfer. The results show that the cooling channels with squared and triangular full-ribs present better cooling effects inside the body blade, reducing the temperature until 10°C at some point in the blade. However, these configurations produce a pressure drop from 3 to 4 times higher than cooling channels without ribs. The half ribs produce lesser temperature decrement, having smaller pressure drop. On other hand, the aspect ratio (P/e) has only effects on the pressure drop.

The flow structures in the cavities of parallel cross-corrugated surfaces, also called chevron geometry, are investigated in this work using an experimental visualization method. An angle of 45° between the corrugations and the main flow direction has been considered. Reviews show that a considerable amount of investigations, mainly experimental, of heat transfer and pressure drop for cross-corrugated plates has been performed, whereas for the flow field in the cavities has only been investigated numerically. The flow visualization experiments are performed inside a water tunnel using a wide range of the hydraulic diameter-based Reynolds number.