Design and Performance Analysis of Composite Airfoil Wind Turbine Blade

Abstract Small horizontal axis wind turbine rotors with composite airfoil rotor blades were designed and investigated in the present study in order to improve its performance in low wind speed and low Reynolds number (Re) conditions for standalone system. The geometrical and aerodynamic nature of a single airfoil small horizontal axis wind turbine blade curtails efficient energy harnessing of the rotor blade. The use of composite airfoil rotor blade improves energy production but imposes uncertainty in determining an optimal design angle of attack and the off design aerodynamic behaviour of the rotor. This research investigated the effects of two airfoils used at different sections in a composite blade and determined the blade’s optimal design angle of attack for maximum power generation. The wind turbine rotor blades were designed using blade element momentum (BEM) method and modelled by SolidWorks software. The SG6042 and SG6043 airfoils were used for the composite airfoil blades. Five wind turbines were designed with rotor blades of design angles of attack from 3° to 7°. The five wind turbine blades were simulated in computational fluid dynamics to determine the optimal design angle of attack. The composite airfoil wind turbine blade showed improved performance, whereas, the wind power generated ranged from 4966 W to 5258 W and rotor power coefficients ranged from 0.443 to 0.457. The blade with design angle of attack of 6° showed highest performance. Keywords: composite airfoil, lift-to-drag ratio, pressure coefficient, Reynolds number, design angle of attack

Effect of Elevated Temperature on Compressive Strength and Physical Properties of Neem Seed Husk Ash Concrete.

This research article published by MDPI, 2020High temperature rise mostly caused by a fire outbreak is currently becoming a threat that endangers concrete's structural performance for buildings and the safety of occupants. The behavior of concrete after fire subjection has been of much interest for the structural materials design purposes. This study investigated the physical properties and the compressive strength of M25 concrete incorporating Neem Seed Husk Ash (NSHA), exposed to and through targeted different levels of temperature (200 °C to 800 °C) for a period of three hours in an electric furnace. The NSHA was produced by calcining neem seed husks at 800 °C for six hours and then sieved through the 125 μm sieve. Different amounts of NSHA were investigated while considering the plain concrete as the control sample. 150 concrete cubes of 150 mm sizes were cast and properly cured for 7 and 28 days. The experimental results show that the compressive strength of the 5% NSHA concrete exposed to temperatures up to 400 °C is 21.3% and 23.8% better than the normal concrete at 7 and 28 curing days, respectively. Surface cracks and spalling are noticeable at 600 °C and 800 °C for all samples considered in this study

A Review on Computational Fluid Dynamics Applications in the Design and Optimization of Crossflow Hydro Turbines

This research article was published by Hindawi, 2021In recent years, advances in using computational fluid dynamics (CFD) software have greatly increased due to its great potential to save time in the design process compared to experimental testing for data acquisition. Additionally, in real-life tests, a limited number of quantities are measured at a time, while in a CFD analysis all desired quantities can be measured at once, and with a high resolution in space and time. )is article reviews the advances made regarding CFD modeling and simulation for the design and optimization of crossflow hydro turbines (CFTs). )e performance of these turbines depends on various parameters like the number of blades, tip speed ratio, type of airfoil, blade pitch, chord length and twist, and its distribution along the blade span. Technical aspects of the model design, which include boundary conditions, solution of the governing equations of the water flow through CFTS, and the assumptions made during the simulations are thoroughly described. From the review, a clear idea on the suitability of the accuracy CFD applications in the design and optimization of crossflow hydro turbines has been provided. )erefore, this gives an insight that CFD is a useful and effective tool suitable for the design and optimization of CFTs

Performance analysis of a runner for gravitational water vortex power plant

This research article published by Wiley & Sons Ltd, 2022Micro-hydropower can be used to meet the needs of both isolated and rural com munities for electricity. Due to its inexpensive initial investment, simple design, easy maintenance and low-head utilisation, the gravitational water vortex power plant (GWVPP) has recently piqued interest. The findings of numerical work employing a numerical simulation and analytical approach for the GWVPP are presented in this study. To understand the influence of each on the efficiency of GWVPP, four parameters (speed, hub-blade angle, number of blades and run ner profile) were explored. Design-Expert software was used to investigate the interplay of each parameter/factor in order to maximise the contribution of each. Design-Optimal Expert's (custom) design tool was used to construct twenty-four experimental runs. To calculate the system efficiency, these runs were simulated in commercial computational fluid dynamics (CFD) software called Ansys CFX. The numerical results were in good agreement with the experimental results, which yieldedR2 values of 0.9507 and0.9603 forflat andcurvedprofiles,respectively.Furthermore, the findings show that the chosen parameters have an impact on the GWVPP's efficiency via interaction as seen in response surface methodology (RSM). Furthermore, numerical analysis increased the curved blade profile runner's total efficiency by 3.65%. In compari son with the unoptimised scenarios, the efficiency of the flat runner profile increased by 1.69%

Preparation and Characterization of Biogenic Chitosan-Hydroxyapatite Composite: Application in Defluoridation

This research article published by Cambridge University Press, Volume 3 Issue 36, 2018In Northern Tanzania, high levels of fluoride in community drinking water supply is recognized as one of the major public health concern, the problem is further ameliorated by presence Escherichia coli and fecal coliform bacteria in surface water and shallow wells. Efforts to decontaminate the water involve mostly the use of low efficient bone char for fluoride removal without disinfecting the pathogens. To address this problem, a robust adsorbent which is capable of removing fluoride and microbes simultaneously with minimal diverse impact on the treated water is necessary. Here we highlight development of composite material developed from recycling of crustacean biomass waste from sea food industry. Chitosan polymer, isolated from prawns shell was composited with crab shell derived brushite (CaHPO4.2H2O) to form chitosan-hydroxyapatite composite. XRD and FT-IR analysis confirmed transformation of brushite phases into hydroxyapatite and formation hybrid composite. Fluoride adsorption tests were performed in batch mode to evaluate effectiveness. Defluoridation capacity of up to 6.4 mg/g in field water containing fluoride concentration of 5-70 mg/L was achieved. The best performance was observed with fluoride concentration of 10 mg/L and below. Apart from fluoride removal, the composite also reduced color tint and microbes from surface water samples. The pH of the treated water in most samples remained around 6.5-8.5, which is acceptable for drinking water

Strength and Durability Properties of Concrete Containing Pumice and Scoria as Supplementary Cementitious Material

This research article was published by Hindawi, 2021Concrete structures suffer serious deterioration under a corrosive environment. Consequently, the service life of these concrete structures is decreased and deteriorates under combined attack of sulphate and chlorides. Most studies confined on single deteriorating factor such as sulphate attack only or chloride attack only but the current study focused on the influence of natural pumice (NP) and natural scoria (NS) on the strength performance of concrete exposed to the combined attack of sulphate and chloride. Portland cement (PLC) was replaced with NP or NS at a substitution level of 10%. Concrete samples were cured in water for the curing period of 28 days. Afterwards, the specimens were immersed in 5% sodium sulphate (Na2SO4), 5% sodium chloride (NaCl), and combined sodium sulphate and chloride solutions for additional curing of 28, 56, and 90 days. /e results were compared between concrete mixes with NP or NS and control mix (CT) with PLC. /e effects of sulphate, chloride, and combined sulphate and chloride were evaluated in terms of change in weight, variation in compressive strength, and degree of damage. Conclusively, the application of NP and NS has extraordinary potential to be utilized as a cementitious material in concrete to increase the resistance against aggressive salts

Capacitive Deionization for the Removal of Paraquat Herbicide from Aqueous Solution

This research article was published by Hindawi, 2021In comparison to other conventional methods like adsorption and reverse osmosis (RO), capacitive deionization (CDI) has only been investigated extensively for the removal of inorganic pollutants from water, demonstrating limited practicality. Herein, the study investigated the use of CDI for the removal of paraquat (PQ) herbicide from water by using commercial activated carbon (AC) electrodes. The CDI performance was examined as a function of the initial PQ concentration, applied voltage, flowrate, treatment time, and cycle stability testing in the batch mode approach. The applied voltage had a beneficial effect on the removal efficiency, whereas the removal efficiency of PQ declined as the initial PQ concentration increased. However, the electrosorption capacity gradually increased with the increase of initial feed solutions’ concentration. The maximum removal efficiency and electrosorption capacity achieved at 5 mg/L and 20 mg/L PQ initial concentrations, an applied voltage of 1.2 V, and 5 mL/min flowrate were 100% and 0.33 mg/g and 52.5% and 0.7 mg/g, respectively. Washing the electrodes with distilled water achieved sequential desorption of PQ, and the process produces a waste stream that can be disposed of or treated further. Therefore, the CDI method is considered a promising and efficient method for removing organic pollutants from water including pesticides

Predicting the lowest effluent concentration in capacitive deionization

This research article published by Elsevier B.V., 2013Capacitive deionization (CDI) is a promising technology for desalination of brackish water with different applications such as in the pharmaceutical industry, semiconductor manufacturing, and domestic use. The CDI cell utilizes an electric potential across two electrodes in which one of the electrodes becomes positively charged and the other becomes negatively charged. Cations and anions are attracted towards the anode and cathode, respectively. The adsorption and desorption mechanism within the CDI cell determines the amount of salt in the effluent stream. Modeling the dynamic response of the effluent concentration is vital to understanding the water purity level. In this paper, the equations predicting the lowest concentration time and lowest concentration have been found using the adsorption cycle mathematical model. During purification process the effluent concentration reaches the highest purity level after a certain period of time. We define the time it takes to reach the highest purity level as lowest concentration time and the corresponding instantaneous effluent purer water is what we call lowest concentration. While the lowest concentration depends on all of the CDI operating parameters i.e., applied potential, capacitance, flow rate, feed concentration, dead volume, and spacer volume, the lowest concentration time depends only on flow rate, dead volume, and capacitance. Using a genetic algorithm, it was found that seawater (32,702 ppm) could be desalinated to as low as 2.1 ppm; which is within the standards for drinking water set by the world health organization

Modeling the capacitive deionization batch mode operation for desalination

This research article published by Elsevier, 2014Capacitive deionization (CDI) is an emerging desalination technology in which saline water flows through a pair of polarized/biased electrodes. The cations and anions are attracted towards the negative and positive electrodes, respectively. In CDI operation there are two possible modes: single pass and batch mode. In single pass operation, saline water passes only once through the CDI cell, whereas in batch mode operation, the fixed volume of saline water is recycled continuously until a steady state is reached. This paper presents the transient response of the CDI cell under batch mode operation. The model is developed by taking into account single pass CDI operation and the mixing phenomena that occur in the recycling tank. The developed model was successfully validated using experimental data, and the model helped to derive the equation for predicting the steady state of the CDI cell for the given operating parameters: flow rate, saline water quantity, CDI capacitance, CDI resistance, spacer volume, dead volume, applied potential, and initial concentration of the saline water

Desalination using capacitive deionization at constant current

This research article published by Elsevier B.V., 2013Capacitive deionization (CDI) is an emerging technology of desalinating brackish/seawater to attain freshwater. The process involves polarization of the two electrodes electrically using direct current; thus the cations and anions are attracted towards the oppositely charged electrode. So far most of the experiments/models involve the charging of the CDI cell at constant voltage. However, charging at constant voltage leads to having a shorter time in a given CDI cell cycle when the system has reached its lowest effluent concentration. This is undesired phenomena. To overcome this problem desalination process is preferred to be performed at constant current. The dynamic response model to describe the variation of the effluent concentration with time under constant current charging has been derived and validated. Also, the effect of processing parameters such as applied current, flow rate, CDI cell dead volume, and capacitance on the lowest effluent concentration is analyzed