37 research outputs found
Structural investigation of the high pressure phases Si(vi), Ge(iv) and Sn<SUB>.8</SUB> In<SUB>.2</SUB> (II)
No full textThe X-ray diffraction patterns of Si(VI) (at 39 GPa), Ge(IV) (at 113 GPa), and Sn8 In2 (II) (at 10 GPa) phases are interpreted on an orthorhombic cell. This cell is similar to that of the X-phase in Sn alloys, which also occurs between the primitive hexagonal and the hexagonal close packed phases. Structures in two space groups, Pnma and Pbcm, with Z = 4 can be fitted to the intensity data. In these the metal atoms have coordination close to 12
Investigation of Co Fe and Pd Metal Substituted TiSnC MAX Phases
No full textMAX phases are compounds consisting of layers with the formula Mn+1AXn, where M represents an early transition metal, A is an element from groups 13, 14, and 15, and X is either C or N.The use of late-transition metals instead of A-site elements can lead to distinct properties in MAX phases and provide opportunities for tailoring their functionality. Co, Fe, and Pd substituted Ti2SnC MAX phases were synthesized using the direct one-step solid-state synthesis method. The successful substitution of Co/Fe at the A(Sn) site of the Ti2SnC MAX phase was confirmed by HR STEM imaging. In the case of Pd, a random distribution was observed, and the precise location of Pd within Ti2SnC remains uncertai
PIV Experimental Comparison of Vertical Axis Wind Turbine Wake with Theoretical Models
No full textVertical Axis Wind Turbine (VAWT) operation is characterized by complex and unsteady three-dimensional fluid dynamics, which presents considerable challenges. One of the crucial points to understand is the complex interaction between rotor, inflow, and wake systems. If we can demonstrate its effectiveness in the complex flow/inflow conditions, will be of great importance. To investigate the wake/wind aerodynamics validate state-of-the-art VAWT wake models, a high ¬fidelity experimental measurement in the domain of VAWT wakes is needed. Computational fluid dynamics (CFD) models for complex wind interactions are far from being feasible. These models are highly time-devouring and computationally expensive, and their cost prohibits the simulation of complex flow configurations. This is usually overcome through the implementation of simple and computationally inexpensive analytical wake models, where the flow conditions are solved through simple analytic expressions and only over specific points of interest. The work aims to realize and validate a simple and efficient analytical wake model (Abkar, 2019 [2]), (Bastankhah & Porté¬Agel, 2014 [7]) for prediction of the wind velocity profile downwind of a VAWT turbine: The best by comparing the modeling results with a set of particle image velocimetry (PIV) measurements of the wakes of an in-house designed VAWT are used as a high-fidelity reference. The present work evaluates and quantifies the influence of the wake deflection produced by the pitch angles of the blades on the scaled VAWT turbine. It reproduces the main phenomena involved in the flow pattern and identifies the general structure of the resulting wake that occurs: under the influence of pitching the blades on the upstream turbine. The configuration consists of a VAWT aligned in the direction of the incoming flow: With a class of cases for different configurations of the turbine are studied for example ¬ deflection of wake through zero pitch, positive 10 degrees pitch, Negative 10 degrees pitch angles (Mendoza et al, 2019 [32]). The available power distribution over other hypothetical downwind turbines due to the influence of wake deflection by the upstream turbine is studied and reported. These interactions are measured with the help of large ¬scale PIV experiments in OJF, TU Delft. Also, an efficacious force balance system for the VAWT rotor is studied, designed, and fabricated (in-house) to calculate the accurate lift and drag forces on the VAWT structure. The stereo particle image velocimetry results are compared with two theoretical works Jensen wake model, [21] and Gaussian-based wake model Abkar [2] and CFD simulations by Huang et al [18]. The study shows a wake shift towards the windward side (cross-flow width), Negative¬ Y direction. For all the pitch cases, maximum for the positive pitch angle and least for a negative pitch angle. The wake shift in the negative ¬Y direction can be caused by the blade rotation, with the clockwise rotation of the VAWT rotor, and the rear blade turning into the incoming flow of wind. The theoretical models especially the Gaussian-based wake model represent the wake deficit in close agreement to the experimental results but fails to account for wake shift and change in wake structure. The CFD simulations reproduce the 3D wake structures consistent with the experiment results but show an early recovery in the wake. The wake recovery with downwind available power is found higher with a positive pitch angle and least with the negative pitch. A study of in-plane velocity vectors indicates crosswind force introducing crosswind momentum to the flow and as a result would give rise to the CVPs, also according to a study by Rolin F, Porte-Agel [38]. The theoretical models do not account for any of these structural changes in wake and the deflections in them. Furthermore, the suitability of these experimental references are used to verify the CFD simulations and analytical models’ range of the fidelityElectrical Engineering | Sustainable Energy Technolog
Underling data for "On the wake deflection of vertical axis wind turbines by fixed-pitched blades"
No full textThe repository contains the underlining data for "On the wake deflection of vertical axis wind turbines by pitched blades"
This repository consists of experimental (PIV and force measurements) data in the wake of VAWTs with different blade pitch angles. The measured cases include an isolated VAWT with -10, 0, 10 degree pitch, respectively.
Author contribution:
Ming Huang: Conceptualization; Methodology; Validation; Experimental design; Carrying out the experiment; postprocessing
Yugandhar Vijaykumar Patil: Design assistant; Carrying out the experiment; postprocessing
Andrea Sciacchitano: Conceptualization; Experimental design; Methodology; Validation;
Delphine De Tavernier: Conceptualization
Carlos Simao Ferreira: Conceptualization; Methodology; Validation; Experimental design
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Sugarcane Bagasse – A By-Product of Sugar Industry, Its Characterisation and Utilization in the Preparation of High Fiber Biscuits
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Underling data for "On the wake deflection of vertical axis wind turbines by fixed-pitched blades"
No full textThe repository contains the underlining data for "On the wake deflection of vertical axis wind turbines by pitched blades"
This repository consists of experimental (PIV and force measurements) data in the wake of VAWTs with different blade pitch angles. The measured cases include an isolated VAWT with -10, 0, 10 degree pitch, respectively.
Author contribution:
Ming Huang: Conceptualization; Methodology; Validation; Experimental design; Carrying out the experiment; postprocessing
Yugandhar Vijaykumar Patil: Design assistant; Carrying out the experiment; postprocessing
Andrea Sciacchitano: Conceptualization; Experimental design; Methodology; Validation;
Delphine De Tavernier: Conceptualization
Carlos Simao Ferreira: Conceptualization; Methodology; Validation; Experimental design
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Understanding the Role of Atomic Ordering in the Crystal Structures of toward Efficient Vapor Phase Furfural Hydrogenation
No full textWe have synthesized ordered NixSny nanoparticles separated by AlO as highly efficient catalysts for the vapor phase hydrogenation of furfural. The NiSn-AlO composite catalysts with different chemical compositions (NiSn, NiSn, NiSn, NiSn, Ni) were prepared through the layered double hydroxide (LDH) route by annealing at 800 °C in the presence of H. NixSny nanoparticles were well dispersed throughout the AlO matrix indicating the high thermal stability of these materials. The effect of different concentration of Ni, Sn, and Al in the formation of NiSn-AlO catalyst was investigated. The X-ray diffraction, transmission electron microscopy, and X-ray absorption fine structure analyses indicate the formation of intermetallic phases with spherical particles having an average size of 30–160 nm. The nanoparticles with different compositions were tested toward the hydrogenation of furfural, and it was found that crystal structure, atomic ordering and composition play crucial roles in the catalytic activity. DFT calculations indicate that the adsorption energy and the geometrical orientation of furfural on the surface of different NixSny-Al2O3 compounds play crucial role in the hydrogenation of furfural. NiSn–AlO was found to be the most efficient catalyst with high furfural conversion (∼65%) and selectivity (57–62%) for furfuryl alcohol
Study of magnetofluidic laser scattering under rotating magnetic field
No full textMagnetic field driven self-assembly of magnetic nanoparticles provides wireless programmable approach for tunable magnetofluidic laser scattering. In this work, we study magnetofluidic laser scattering from a commercial aqueous magnetic fluid (EMG 707) under an external rotating magnetic field. A set-up is developed to generate rotating magnetic field for the purpose. Self-assembled magnetic nanoparticle structures in the form of chains and bundles are formed along the magnetic field. This creates a linear streak formation in the forward laser scattering. Rotating magnetic field produces rotating linear streak. We report our initial results of rotating linear streaks at 3 rpm, 6 rpm and 10 rpm and our analysis of the patterns. The studies are useful for developing magnetic fluid based optical devices.Published versio
Comparative Experimental Study on Torsional Behavior of RC Beam Using CFRP and GFRP Fabric Wrapping
No full textAbstractFiber reinforced polymer (FRP) as an external reinforcement is used extensively to enhance the strength requirement related to flexure and shear in structural systems. But the strengthening of members subjected to torsion is yet to be explored as Torsion failure is a brittle form of failure. In present experimental study deals with the torsional strengthening of Reinforced Concrete beams using epoxy bonded Fiber- Reinforced Polymer (FRP) fabric. Total Thirty nine rectangular beams of size 150mm × 300mm and 1200 in length are casted. Out of which, three beams are control beam and remaining thirty six beams are classified into two groups. One with CFRP fabric wrapping and another with GFRP fabric wrapping. With various wrapping patterns. The applied CFRP and GFRP configurations are U-jacketed, vertical strips with spacing, and edge strips along with vertical strips along its entire length. Torsional capacity of beams of two groups is compared with control specimen with respect to torsional moment, angle of twist and ductility factor and it was observed that CFRP fabric bonded beam shows more torsional strength than the GFRP bonded beam
Experimental study of the wake interaction between two vertical axis wind turbines
No full textWakes and wake interactions in wind turbine arrays diminish energy output and raise the risk of structural fatigue; hence, comprehending the features of rotor–wake interactions is of practical relevance. Previous studies suggest that vertical axis wind turbines (VAWTs) can facilitate a quicker wake recovery. This study experimentally investigates the rotor–wake and wake–wake interaction of VAWTs; different pitch angles of the blades of the upwind VAWT are considered to assess the interactions for different wake deflections. With stereoscopic particle image velocimetry, the wake interactions of two VAWTs are analysed in nine distinct wake deflection and rotor location configurations. The time-average velocity fields at several planes upwind and downwind from the rotors are measured. Additionally, time-average loads on the VAWTs are measured via force balances. The results validate the rapid wake recovery and the efficacy of wake deflection, which increases the available power in the second rotor.Wind EnergyAerodynamic
