Mechanical Engineering

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Shiv Nadar University

Superhydrophobic surfaces with high adhesion have attracted huge attention in recent research works due to their versatile applications including transportation of microdroplet without any loss. Modification of metallic surfaces to achieve such properties is important to extend their applications. Especially, the superhydrophobic surfaces with very low bacterial adhesion have attracted intense attention in medical, food, and pharmaceutical industries. Here, we have fabricated different micropatterns on aluminium surfaces using a simple and cost-effective micro-imprinting technique. The surface chemistry was modified through a coating of low surface energy material 1H, 1H, 2H, 2H-perfluorooctyl-trichlorosilane (FOTS) using vapor deposition technique. Surface morphology of the samples was investigated using scanning electron microscopy (SEM) and contact profilometer. Results show a significant influence of the surface morphology on the wetting, adhesion and anti-bacterial properties. Surfaces composed of discrete micropillars showed higher de-wetting compared to surface containing continuous zig-zag micro lines even despite lower roughness factor. However, the opposite trend was observed in case of adhesion. These results are explained based on wetting state and difference in liquid-air interface pinning. Further, the developed samples showed higher water-retaining ability compared to rose-petal along with superhydrophobicity. The surface with micropillar structures with higher roughness factor exhibited improved non-fouling behavior which has been quantified by spot assay and atomic force microscopy (AFM). This study opens up the possibility of fabricating multifunctional metal surfaces on a large scale by a cost-effective, environment friendly and easily scalable processing route. © 2020 IOP Publishing Ltd.

(SoE) School of Engineering

Physics

(SoNS) School of Natural Sciences

Surface Topography: Metrology and Properties

Effect of topography and chemical treatment on the hydrophobicity and antibacterial activities of micropatterned aluminium surfaces

Present work shows the flow effect of water mass per unit time (MFR) on the life cycle conversion efficiency (LCCE) of a single slope solar desalination unit (SSSDU) coupled with N identical evacuated tubular collectors (N-ETC). The analysis is observed for a typical days of May and December for the atmospheric situation of New Delhi with the help of analytical program fed in MATLAB. The input data required for the numerical computations have been taken from IMD, Pune, India. The average value of annual energy output has been computed based on the enegy outputs of summer and winter seasons followed by the evaluation of LCCE for the system. It has been concluded that the value of LCCE diminishes with the raise in the value of fluid flow mass/ unit time and values of LCCE becomes almost constant beyond 0.044 kg/s at given values of water depth and number of collectors. It has also been observed that the value of LCCE has similar trends at other number of collectors. © 2019 Elsevier Ltd.

World University root node

Materials Today: Proceedings

Effect of flow of fluid mass per unit time on life cycle conversion efficiency of single slope solar desalination unit coupled with N identical evacuated tubular collectors

Utilization of solar photovoltaic (PV) as a power source in water pumping applications has emerged as one of the valuable solar applications. Solar PV water pumping system is used to fulfill the demand of water in the field of irrigation, livestock watering, and village water supply. Understanding of system design and selection of appropriate design parameters are essential to attain consistent and economical performance of any system. To design a solar water pumping system collection of the information regarding the system components and local climate data of the location are required. This information helps to obtain preferred design and results. In the present paper design optimization of PV system is done by simulation software tool PVsyst 5.52. This simulation software helps to design the system and shows how the different parameters affect the system performance results. Selection of PV array, controller, pumping unit, water supply network is needful to fulfill design requirements. The performance evaluation of a system located at Karansar, Jaipur (Rajasthan) is done with help of simulation software by using existing local data. The theoretical and simulation results are used to understand the system design and its performance by taking different parameters into consideration. © 2019 Elsevier Ltd. All rights resrved.

Design optimization of solar PV water pumping system

In this current study, two post-processing techniques, i.e. microwave annealing and cryogenic treatment were employed on WC-10Co-4C detonation gun (D-gun) coating to improve the tribological properties. The effect of both the post-treatment on the microstructure and mechanical properties was studied using optical micrograph (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy-dispersive X-ray spectroscopy (EDS). Microwave annealing, resulted in a significant change in the size and morphology of WC particles. However, cryogenic processing showed minimal variation with slight decrease in the WC particle size. Phase changes were observed after both the post-treatment techniques. The cryogenically treated sample showed considerable improvement in the hardness while there was a slight reduction in the hardness after microwave processing. Among all the coatings, the microwave processed sample had the highest fracture toughness. The improvement in hardness after the cryogenic process was attributed to the formation of g phase and the presence of nano precipitates in the coating matrix. Cryogenically treated coating showed significant improvement in the wear resistance of the WC D-gun coating due to the improvement in the microhardness in the coating. © 2019 Elsevier Ltd. All rights reserved.

Wear behavior of microwave-annealed and cryogenically treated thermal spray coatings: A comparative evaluation

In this paper, the vibrational response of the functionally graded plate has been carried out using non-polynomial based algebraic shear deformation theory. Hamilton’s variational principle has been used in deriving the governing equations. The Navier solution technique has been employed to solve the governing equation in conjunction with boundary conditions which are simply supported. In addition to these, the power-law governing equations have been considered for calculating the effective material properties of FGM and its mechanical properties are considered to be changing in the direction of thickness. The non-dimensional frequency has been evaluated for several vibrating modes of functionally graded thin and thick plates. The frequency parameter has also been evaluated for different aspect ratios and thickness ratios. © Springer Nature Singapore Pte Ltd. 2020.

Lecture Notes in Mechanical Engineering

Vibration Response of Metal-Ceramic Based Functionally Graded Plate Using Navier Solution

The exergoeconomic and the enviroeconomic analyses of basin type single slope distiller unit based on solar energy can play an important role for mitigating the contemporary problem of acute shortage of drinking water throughout the world particularly developing and under developed countries. The technology of solar distiller unit has been known to humankind since the 16th century; however, it has not been preferred for purifying water on a large scale till date because of low potable water output, high initial investment, and non-availability of a technician at the local level. This technology is simple in nature and has the potential to mitigate the drinking water shortage; however, it has not been fully explored so far. A lot of configurations have been reported by various researchers since the development of solar distiller unit technology. This paper summarizes some of the important contributions reported so far on the basis of exergoeconomic and enviroeconomic parameters of single slope solar desalination units by incorporating the effect of nanofluid. A comparative study has been presented followed by a detailed discussion about exergoeconomic and enviroeconomic parameters of a single slope solar desalination unit loaded with/without nanofluid. It has been observed that the application of water-based nanofluid in the distiller unit results in the enhancement of performance. At last, the future scope has been presented. © 2020 IOP Publishing Ltd. All rights reserved.

Fulltext

IOP Conference Series: Materials Science and Engineering

Exergoeconomic and enviroeconomic analyses of single slope solar desalination unit loaded with/without nanofluid: A comprehensive review

Savonius wind turbines are special class of vertical axis wind turbines (VAWTs). These are low-cost drag-driven turbines and are known to be inefficient. It is proposed in this study that a simple modification to the turbine blade design can yield a significant improvement in power efficiency. The performance of the new design is extensively studied on OPENFOAMv1812, a popular open source computational fluid dynamics (CFD) library. The flow equations coupled with equations of rotation of the turbine are solved on an overset mesh framework. This study also serves as a validation of recently released overset support in OPENFOAM. The turbulence is incorporated by coupling Reynolds-averaged Navier-Stokes (RANS) with shear stress transport (SST) κ-ω eddy viscosity turbulence model. The turbulence parameters are set to produce a flow with the Reynolds number, Re=4.8 × 105. To have better confidence in simulations, this study also presents a comparison of numerical flow over conventional Savonius turbine designs with the published data. It is observed that a majority of CFD analysis on wind turbine designs are performed for the fixed tip speed ratio on a traditional static mesh structure. But, in this CFD study, a winddriven rotation of Savonius turbine is simulated on an overset dynamics approach. The results of the study are compared and discussed based on the predicted moment and power coefficients, pressure variation on the blades, flow velocity field, and wake analysis. The study indicates that the blade design presented here has a potential to increase the power efficiency of a Savonius wind turbine by 10-28\%. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

Mathematics

Journal of Energy Resources Technology, Transactions of the ASME

Improvement in savonius wind turbines efficiency by modification of blade designs - A numerical study

This paper deals with joint optimization of production scheduling and group maintenance planning in single machine system with multi units arranged in series. The objective is to achieve optimum production sequence, preventive maintenance (PM) intervals and grouping of units which minimize the total integrated cost per unit time of the system. Teaching-Learning Based Optimization (TLBO) algorithm is applied to optimize the objective function. The peculiarity of TLBO as against other algorithms is that it is independent of algorithm specific parameters. The largest order value rule is utilized to retrieve the permutation vector while grouping of units is performed under PM intervals. Computational results reveal the effectiveness of the proposed approach. © 2020 The Authors.

Procedia CIRP

Integration of production scheduling and group maintenance planning in multi-unit system employing TLBO algorithm

Herein, bimodal-reinforced AlCoCrFeNi complex concentrated alloy composite cladding on stainless steel 316L substrate using microwave hybrid processing is synthesized. Detailed microstructural analysis of the claddings shows the presence of cellular structure A2 (disordered BCC) with intermetallics (B2 (ordered BCC) and σ phases) at the intercellular regions. The presence of Cr23C6 is also observed for the reinforced claddings due to the dissociation of the SiC particles. The bimodal-reinforced cladding shows the highest hardness (in excess of 800 HV) and fracture toughness (≈12 MPa√m), followed by micro- and nanocomposite claddings. Under slurry erosion condition, the bimodal composite cladding exhibits 10 times better erosion resistance than stainless steel 316L and nonreinforced cladding (1.5–2 times), respectively, at oblique angle followed by nano- and microreinforced unimodal counterparts. The outstanding performance of the bimodal composite cladding under both test conditions is related to higher hardness, fracture toughness, and resistance to plastic deformation. The detailed analysis of the eroded samples shows microcutting and ploughing as a dominant mechanism at an oblique angle while platelets, cracks, and microindents being the contributing factors for erosion at the normal impact angle. © 2020 Wiley-VCH GmbH

Advanced Engineering Materials

Slurry Erosion–Corrosion of Bimodal Complex Concentrated Alloy Composite Cladding

Vibrational study of the porous functionally graded plate with geometric discontinuities and partial supports has been presented in the present paper. The kinematics of functionally graded plate is based on the refined exponential shear deformation theory. The displacement field has been refined by dividing the in-plane and out of the plane displacements into bending and shear components. The theory accounts for the nonlinear transverse shear stress variation along with the thickness with only four unknowns. The closed-form solution (Navier’s solution), as well as FEM-based solution, have been used for the vibration analysis of functionally graded plate. The geometric discontinuities have been incorporated in terms of a circular cut-out of different sizes at the center of the plate. Modified rule of mixtures, modified sigmoid law, and trigonometric law have been used to compute the effective material properties of the functionally graded plate. A C0 continuous iso-parametric FEM formulation has been used to attain the results in the case of FEM solution, and the efficacy of the present solution is demonstrated by comparing the results with the available literature. The results reflect that the porosity inclusion, circular cut-out, and position of the boundary constraints have a notable influence on the fundamental frequency of the functionally graded plate. It is also concluded that after a specific radius of circular cut-out, the vibration response of functionally graded plate exhibits nonlinearity in nature. © IMechE 2020.