Search Results (2)

This study proposes a new method of symmetrical stirring using an anchor paddle to improve the heating uniformity of liquids. To simulate the complex physical process of microwave heating a fluid while stirring it, the finite element method (FEM) and the arbitrary Lagrangian–Eulerian (ALE) method were utilised to model the interactions between electromagnetics, heat transfer, and fluid flow. The temperature coefficient of variation (COV) of the water when subjected to microwave heating and the symmetrical stirring paddle decreased by an 11.2–81.5% compared to that achieved by the traditional rotating turntable method, and it further decreased as the stirring frequency increased. This implies that the stirring method performed more favourably than the rotation method in improving the uniformity of the microwave heating. The distributions of the three physical fields indicated that symmetrical stirring enhanced the axial fluid flow and heat transfer, reducing the large intrinsic temperature difference along the vertical direction. Furthermore, the computation results were validated experimentally, showing that the proposed method is sufficiently accurate for evaluating the uniformity of microwave heating. Full article

Wave energy, a form of renewable energy, is derived from the movement of sea waves. Wave energy generation devices are technologies designed to harness this resource and convert it into electricity. These devices are classified based on their location, size, wave direction, and operating principle. This work presents the design of an oscillating device for harnessing wave energy. For this purpose, computational fluid dynamics and response surface methodology were employed to evaluate the influence of the percentage of the blade height submerged below the water surface (X₁) and the distance from the device to the breakwater in terms of the percentage of the wave length (X₂). The response variable studied was the hydrodynamic efficiency ($\eta$) of the device. Transient fluid dynamic simulations were carried out using Ansys Fluent software 2023 R1, with input conditions based on a wave spectrum characteristic of the Colombian Pacific Ocean. Analysis of variance determined that both factors and their interaction have significant effects on the response variable. Using the obtained regression model, the optimal point of the system was determined. Numerical results showed that the maximum $\eta$ of the system was achieved when the device was submerged at 75% of its height and was positioned 10% of the wave length away from the vertical breakwater. Under this configuration, $\eta$ was 64.8%. Experimental validations of the optimal configuration were conducted in a wave channel, resulting in a $\eta$ of 45%. The difference in efficiencies can be attributed to mechanical losses in the power take-off system, which were not considered during the numerical simulations. Full article