110 research outputs found
Supplemental Material - Vibrations of composite structures: Finite element and analytical investigation
No full textSupplemental Material for Vibrations of composite structures: Finite element and analytical investigation by Ashkan Farazin, Chunwei Zhang and Azher M Abed in Polymers and Polymer Composites</p
Distribution System Reconfiguration with Soft Open Point for Power Loss Reduction in Distribution Systems Based on Hybrid Water Cycle Algorithm
No full textIn this paper, the role of soft open point (SOP) is investigated with and without system re-configuration (SR) in reducing overall system power losses and improving voltage profile, as well as the effect of increasing the number of SOPs connected to distribution systems under different scenarios using a proposed hybrid water cycle algorithm (HWCA). The HWCA is formulated to enhance the water cycle algorithm (WCA) search performance based on the genetic algorithm (GA) for a complex nonlinear problem with discrete and continuous variables represented in this paper by SOP installation and SR. The WCA is one of the most effective optimization algorithms, however, it may have difficulty striking a balance between exploration and exploitation due to the nature of the proposed nonlinear optimization problem, which mostly causes slow convergence and poor robustness. Consequently, the HWCA proposed in this paper is an efficient solution to improve the balance between exploration and exploitation, which in turn leads to improving the WCA’s overall performance without the possibility of getting trapped in local minima. Several cases are studied and conducted on an IEEE 33-node and the IEEE 69-node to investigate the real benefit gained from using SOPs alone or simultaneously with the SR. Based on the obtained results, the proposed HWCA succeeds in enhancing the performance of the proposed test systems considerably in terms of loss reduction (e.g., 31.1–63.3% for IEEE 33-node and 55.7–82.1% for IEEE 69-node compared to the base case) and voltage profile when compared to the base case while maintaining acceptable voltage magnitudes in most cases. Furthermore, the superiority of the proposed method based on the HWCA is validated when compared with the GA and WCA separately for both test systems. The obtained results show the outperformance of the proposed HWCA in attaining the best optimal solution with the least number of iterations
CHARACTERISTICS OF NATURAL CONVECTION FLOW AND HEAT TRANSFER OF PARALLELOGRAMIC ENCLOSURE WITH AN INNER CIRCULAR CYLINDER USING LIQUID NANOFLUIDS
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Modeling the Thermal Performance for Different Types of Solar Chimney Power Plants
No full textNowadays, due to restrictions on fossil fuels, the use of renewable energies is increasing day by day. Among renewable energies, solar energy has received more attraction due to its availability in all places. Among solar energy technologies, the solar tower has been welcomed due to its high power generation of electrical energy. For accurate modeling of the studied system, each component of the system has been evaluated and modeling has been done. Therefore, in this research, solar tower modeling has been conducted to achieve high electrical energy production, and to better compare the production rate, 5 cities in Iran with different weather conditions have been considered. According to the results, it can be mentioned that the highest production power by the studied system is related to Shiraz city with an average production of 20 kW/m2, and among the cities studied, the lowest rate is related to Mashhad with a production power of 15 kW/m2
Using KDF material to improve the performance of multi-layers filters in the reduction of chemical and biological pollutants in surface water treatment
No full textMulti-layers filters are usually used in conventional water treatment plants to purify water, reduce turbidity, and remove plankton and undesired odours. Multi-layers filter consists of basic layers represented in graded sand and supporting gravel layers. This research aims to study the efficiency of such filters after the addition of new layers made of copper and zinc particles by 50% per each with high purity, which are traditionally called KDF (Kinetic Degradation Fluxion). The purpose of adding such layers is to increase the efficiency of filters in the removal of diverse chemical contaminants of heavy elements (Lead, Nickel, iron, etc.), and chlorine to use them in traditional or advanced filter stations, such reverse osmosis plants or ion exchange water filters. A glass tube was filled with KDF, sand and gravel layers and used as a multi-layer's filter, and tests were carried out on a water sample that has been prepared in the lab with concentration of 2 mg/l for heavy elements and 5 mg/l for chlorine. Flow rates of the tested water sample were 20, 40, 60, 80 and 100 l/hr. The results show a very high efficiency of such filters to remove of chlorine from the treated water by 90% and more, while the efficiency of the modified filter to remove lead, nickel and iron was 92%, 88%, and 67% respectively; however, there was no significant records in removing the biological contaminants. Keywords: Multi-layers filters, KDF, Chlorine, Heavy metals, Water treatmen
Numerical simulation on heat transfer augmentation by using innovative hybrid ribs in a forward-facing contracting channel
No full textThis study aims to investigate the thermal behavior and aerodynamic phenomena in a heated channel with varied rib configurations using computational fluid dynamics (CFD) simulations. Incorporating ribs in such systems enhances heat transfer and increases flow resistance and manufacturing costs. Understanding heat exchanger theory, measurement methods, and numerical calculations are crucial for creating efficient heat exchangers. The current research employs numerical analysis to assess the impact of hybrid ribs on heat transfer enhancement in forward-facing contracting channels (FFS). A two-dimensional forced convection heat transfer simulation under turbulent flow conditions was performed, considering the presence and absence of ribs with dimensions of 1 cm by 1 cm and spaced 11 cm apart. The arrangement of the ribs causes symmetrical temperature and flow distribution after and before each rib. The results demonstrate that the use of hybrid ribs outperforms the use of individual rib configurations in terms of thermal performance. This is due to the distinct flow patterns generated as the fluid passes through each rib. The triangle ribs had a more significant impact on the pressure drop than other rib configurations, while the cross ribs showed a lesser effect. The ribs improve the heat transfer coefficient while increasing the pressure drop, and the values of the Reynolds number were found to be directly proportional to the heat transfer coefficient and the pressure drop. The study concludes with a qualitative and quantitative analysis demonstrating the accuracy and coherence of the obtained computational result
Control of thermal and fluid flow characteristics of an oscillating cylinder by porous media
No full textThe present research aims to study the effect of variables including permeability and thickness of porous media on the thermal and hydrodynamic behavior of an oscillating cylinder at a constant temperature. The finite volume technique is employed to model the flow field for various thicknesses of the porous layer and Darcy numbers at low Reynolds numbers. According to the results, raising the Reynolds number and decreasing the Darcy number will reduce the length of the wakes created behind the cylinder. The separation point occurs earlier as the permeability decreases. Additionally, increasing the porous media thickness and decreasing the Darcy number leads to a decline in the amplitude of oscillation of lift and drag coefficient and amplitude of oscillation in lateral and longitudinal directions. Using the porous layer, the amplitude of the displacement of the cylinder is reduced by about 55 %. Thickness, Darcy number, and the thermal conductivity ratio influence the average variation of the Nusselt number in porous media. For any Darcy number with a specific thermal conductivity ratio, the Nusselt number of the cylinder with a porous layer is larger than the one without porous media. For the oscillating cylinder with Da = 0.001, Re = 90, ks/kf = 1000 and a 0.3 porous layer thickness, it has been taken for a 25 % augment in heat transfer
Analytical and Numerical Solutions for the Thermal Problem in a Friction Clutch System
No full textThe dry friction clutch is an important part in vehicles, which has more than one function, but the most important function is to connect and disconnect the engine (driving part) with driven parts. This work presents a developed numerical solution applying a finite element technique in order to obtain results with high precision. A new three-dimensional model of a single-disc clutch operating in dry conditions was built from scratch. As the new model represents the real friction clutch including all details, the complexity in the geometry of the clutch is considered one of the difficulties that the researchers faced using the numerical solution. The thermal behaviour of the friction clutch during the slip phase was studied. Meanwhile, in the second part of this work, the transient thermal equations were derived from scratch to find the analytical solution for the thermal problem of a clutch disc in order to verify the numerical results. It was found, after comparison of the numerical results with analytical results, that the results of the numerical model are very accurate and the difference between them does not exceed 1%
Thermal and flow performance analysis of a concentrated linear Fresnel solar collector with transverse ribs
No full textData availability statement: The original contributions presented in the study are included in the article/Supplementary Material; further inquiries can be directed to the corresponding authors.Copyright © 2023 Hasan, Sherza, Abed, Togun, Ben Khedher, Sopian, Mahdi and Talebizadehsardari. This article deals with the impact of including transverse ribs within the absorber tube of the concentrated linear Fresnel collector (CLFRC) system with a secondary compound parabolic collector (CPC) on thermal and flow performance coefficients. The enhancement rates of heat transfer due to varying governing parameters were compared and analyzed parametrically at Reynolds numbers in the range 5,000–13,000, employing water as the heat transfer fluid. Simulations were performed to solve the governing equations using the finite volume method (FVM) under various boundary conditions. For all Reynolds numbers, the average Nusselt number in the circular tube in the CLFRC system with ribs was found to be larger than that of the plain absorber tube. Also, the inclusion of transverse ribs inside the absorber tube increases the average Nusselt number by approximately 115% at Re = 5,000 and 175% at Re = 13,000. For all Reynolds numbers, the skin friction coefficient of the circular tube with ribs in the CLFRC system is larger than that of the plain absorber tube. The coefficient of surface friction reduces as the Reynolds number increases. The performance assessment criterion was found to vary between 1.8 and 1.9 as the Reynolds number increases
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