Mechanical Engineering

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

In the present communication, a hybrid mixed mode greenhouse solar dryer, integrated with partially covered number of photovoltaic thermal (N-PVT) solar air collectors has been proposed for drying and different performance parameters are evaluated for the climatic conditions of New Delhi, India. Thermal modelling has been done for the drying system and analytical expressions for different parameters such as crop temperature, greenhouse temperature, outlet air temperature of collector and cell temperature have been obtained. The set of governing equations has been solved with the help of MATLAB 2013a. Further, the effect of mass flow rate and variation of number of air collectors on thermal energy, electrical energy, equivalent thermal energy, thermal exergy efficiency and overall thermal efficiency have been calculated. It was found that with variation of number of air collectors from 1 to 5, equivalent thermal energy, equivalent thermal efficiency and equivalent exergy efficiency changes from 3.24 to 10.57 kWh/day, 61.56%–42.22% and 28.96%–19.11% respectively. © 2017 Elsevier Ltd

(SoE) School of Engineering

World University root node

Energy

Energy and exergy analysis of a mixed-mode greenhouse-type solar dryer, integrated with partially covered N-PVT air collector

In the paper, an attempt has taken to analyze the energy of N photovoltaic thermal (PVT)-compound parabolic concentrator (CPC) water collectors connected in series. The analysis has been examined for cold climate condition where high fossil fuels are need to get thermal energy. Two fluids has been considered: (i) water and (ii) air. The comparison has been made with two different fluids on partially covered N photovoltaic thermal-compound parabolic concentrator (PVT-CPC) collector connected in series. Here, the collector of proposed system is partially covered with 25% of PV module. The thermal modelling has been developed with basic energy balance equation of each component of proposed system. The outlet at Nth of partially covered Photovoltaic thermal (PVT)-compound parabolic concentrator (CPC) collectors has been obtained. The expression of analytical temperature dependent electrical efficiency of proposed system has been derived. The analysis has been carried out for clear day condition in month of January at Srinagar, India. The maximum thermal energy has been found 12.92 kWh and 3.72 kWh per day for fluid: water and air respectively and thermal exergy has been found 1.63 kWh and 0.55 kWh per day with eight number of collector. © 2016 IEEE.

2nd IEEE International Conference on Innovative Applications of Computational Intelligence on Power, Energy and Controls with their Impact on Humanity, CIPECH 2016

Energy performance of partially covered N photovoltaic thermal-compound parabolic concentrator (PVT-CPC) collector for cold climate condition

High entropy alloys (HEAs) represent a new paradigm of structural alloys comprising of multiple principal elements in equimolar or near-equimolar concentration. The superior corrosion and oxidation resistance of HEAs at high temperature make them attractive for several structural applications. In this context, erosion behavior of HEAs has been largely unexplored. In this study, the slurry erosion performance of single phase Al0.1CoCrFeNi high entropy alloy was investigated. For comparison, mild steel and stainless steel (SS316L) were also investigated under similar conditions. The slurry erosion was conducted at different impingement angles and at a constant velocity of 20 m/s. The microstructural and mechanical characterization were conducted using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), nanoindentation and micro-hardness testing. Similar to the mild steel and stainless steel, HEA also showed ductile mode of erosion. The erosion rate for HEA was found to be higher compared to stainless steel, however in spite of lower tensile strength and hardness, HEA exhibited higher erosion resistance compared to mild steel. The high erosion resistance of HEA compared to mild steel is explained on the basis of its work hardening behavior, low stacking fault energy, and superior corrosion resistance. Erosion response of the investigated materials showed significant correlation with ultimate strength and ultimate resilience. In depth analysis of the eroded HEA samples showed ploughing as the prominent material removal mechanism at oblique angles compared to micro-cutting for SS316L and mild steel. In contrast, highly deformed and work-hardened platelets were observed at normal impingement angle for all materials. © 2017 Elsevier B.V.

Wear

Slurry erosion behavior of high entropy alloys

Marine and off-shore components including propellers, pumps, valves, pipelines and other submerged surfaces are subjected to severe degradation by erosion. Impingement of solid particles mixed in a liquid, referred as slurry, leads to significant material loss and shortens the life span of components. Tailoring the surface properties of materials is an economical way for addressing their degradation. Surface modification through high strain-rate deformation is widely used to enhance functional properties of materials. However, surface modification, particularly at low temperature, is extremely challenging for high strength materials such as stainless steel and has not been investigated comprehensively so far. In the present work, high strain-rate deformation of austenitic steel, SS316L, was performed by innovative submerged friction stir processing technique. For comparative studies, friction stir processing was also performed under ambient cooling conditions. Electron back scatter diffraction studies showed significant grain refinement for the sample processed under submerged conditions. The erosion behavior of as-received and processed steel was investigated using slurry erosion tests. Erosion tests were performed at constant impact velocity of 20 m/s and particle size, while varying the impingement angles. The sample processed under submerged conditions showed nearly two times higher erosion resistance compared to as-received steel. The enhancement in erosion resistance is explained using structural rejuvenation achieved at high strain-rate deformation. All the samples showed similar erosion mechanisms with micro-cutting and ploughing being evident at acute angles and platelet mechanism at normal impingement angle. Erosion phenomena showed a strong correlation with material's hardness at oblique impingement angle while, erosion behavior at normal impingement is explained by the flow work given as hardness to elastic modulus ratio. The study provides fundamental insights into material design for advanced structural applications. © 2017 Elsevier B.V.

High strain deformation of austenitic steel for enhancing erosion resistance

In present communication, greenhouse solar dryer under forced mode integrated with different types of photovoltaic (PV) technologies have been proposed. Further, various parameters have been evaluated on environmental point of view for different weather condition of New Delhi, India. For numerical analysis, radiation data and ambient air temperature have been taken from IMD (Indian Meteorological Department), Pune. Further, different parameter such as crop temperature, greenhouse temperature and cell temperature have been calculated with experimental validation by the help of MATLAB 2013a. Overall (equivalent) thermal energy found to be 1838.16, 1740.98, 1351.22, 1472.12 and 1527.86 kWh for c-Si, p-Si, a-Si, CdTe and CIGS PV technologies integrated with drying system respectively on yearly basis. Further, embodied energy, energy payback time, CO2 mitigation and carbon credit earn through different PV drying system have also been calculated. It was found that payback time for c-Si, p-Si, a-Si, CdTe and CIGS system are 1.13, 0.98, 0.93, 0.82, and 0.39 years respectively on the basis of equivalent thermal energy. © 2017 Elsevier Ltd

Journal of Cleaner Production

Environ economic analysis of various types of photovoltaic technologies integrated with greenhouse solar drying system

Advances in Transdisciplinary Engineering

<p>Manufacturability Analysis for Welding – A Case Study Using Howtomation© Suite</p>

Surface modification is a promising method to solve the tribological problems in microsystems. To modify the surface, we fabricated hierarchical patterns with different pitches of nano-scale features and different surface chemistries. Micro- and nano-patterns with similar geometrical configurations were also fabricated for comparison. The nano-tribological behavior of the patterns was investigated using an atomic force microscope at different relative humidity levels (5\% to 80\%) and applied normal loads (40 nN to 120 nN) under a constant sliding velocity. The results showed significant enhancement in the de-wetting and tribological performance of the hierarchical patterns compared with those of flat and micro- and nano-patterned surfaces. The PTFE-coated hierarchical patterns showed similar dynamic contact angles (advancing and receding) to those of the real lotus leaf. The influence of relative humidity on adhesion and friction behavior was found to be significant for all the tested surfaces. The tribological performance was improved as the pitch of the nano-scale geometry of the hierarchical pattern increased, even though the wetting property was not influenced significantly. A model was proposed based on the role of intermolecular force to explain the effect of the pitch of the hierarchical patterns on the adhesion and friction behavior. According to the model based on the molecular force, the contact between a ball and the patterned surface was a multi-asperity contact, contrary to the single-asperity contact predicted by the Johnson-Kendall-Roberts (JKR) and Maugis-Dugdale (MD) models. The strong intermolecular forces, which are activated in the confined spaces between the adjacent nano-pillars and the ball, contributed to the contact area and hence the adhesion and friction forces. © The Royal Society of Chemistry 2016.

Fulltext

Soft Matter

Nanotribological and wetting performance of hierarchical patterns

In this research paper, a hybrid photovoltaic-thermal (PVT) single slope roof integrated greenhouse solar dryer under natural and forced mode has been tested for climatic condition of New Delhi, India. Thermal modelling of PVT dryer has been experimentally validated under natural and forced mode without load condition. Further, characteristic curves have also been discussed on the basis of thermal efficiency, overall thermal efficiency, overall exergy efficiency and solar cell efficiency including the effect of packing factor and mass flow rate. The thermal energy decreased and the electrical energy increased by 76.39% and 88.73% respectively with increment in packing factor of PV module. It was also found that with increment in mass flow rate, the thermal energy increased by 89.44% and 65.70% for natural and forced mode respectively. © 2016 Elsevier Ltd

Solar Energy

Thermal analysis of photovoltaic-thermal (PVT) single slope roof integrated greenhouse solar dryer

In present study, study has taken attempt to show the analysis of N-number of photovoltaic thermal (PVT)-compound parabolic concentrator (CPC) water collectors connected in series water collectors under constant collection temperature mode for the point of user's demand unlike constant flow rate mode. The performance has been examined for thermal energy, thermal exergy and overall thermal energy of partially covered (N) number of Photovoltaic thermal-compound parabolic concentrator collectors connected in series has been analyzed. Here, the collector of present system is partially covered with 50% of PV module. The thermal modelling has been developed with basic energy balance equation of each component of proposed system. The outlet at Nth of partially covered Photovoltaic thermal (PVT)-compound parabolic concentrator (CPC) collectors has been obtained. The expression of analytical temperature dependent electrical efficiency of proposed system has been derived. The analysis has been carried out for clear day condition in month of January at New Delhi, India. The maximum thermal energy has been found 18.14 kWh per day and electrical energy has been found 1.30 kWh per day with constant outlet collection temperature at 67 °C. © 2016 IEEE.

International Conference on Emerging Trends in Electrical, Electronics and Sustainable Energy Systems, ICETEESES 2016

Energy analysis of partially covered number (N) of photovoltaic thermal-compound parabolic concentrator collectors connected in series at constant collection temperature mode

Food is necessity for human being. As the world population is increasing, it is very difficult to fulfil everyone's need of food. One of the alternatives of this problem is the preservation of crops, vegetable and fruits when it is available in abundant amount. Drying is one of the best methods to preserve agricultural products for long time but it requires lot of energy. As availability of electricity per capita in developing and under developed countries is very less, thus the electricity uses for heating purpose cannot be economically and environmentally justified option. So entrapment of thermal energy from solar radiation may be the best option for drying. Solar energy can be utilized for drying in different ways namely open sun drying and closed drying (direct and indirect). Open sun drying have various disadvantages like contamination of dust particles, bacteria in crop, decolouration of the product after drying etc. To overcome these problems greenhouse drying or closed drying has been developed. This review is an attempt to explore different types of drying systems was developed across the world. Further different thermal modelling, mathematical modelling and performance evaluation on the basis of characteristic curve have been discussed. One of the thermal modelling has been discussed in detail to evaluate heat transfer coefficient, heat absorbed and moisture evaporate with experimental validation to give practical exposure to the researchers. © 2016 Elsevier Ltd