ABSTRACT
The present work aims to investigate thermal performance of a solar flat plate collector using water and Cu-MWCNTs nanoparticle-based hybrid nanofluid both experimentally and numerically. X-ray diffraction and FESEM with EDAX mapping were performed to characterize nanoparticles. The experimental setup was developed for thermal performance of FPC varying flow rates (0.5, 1.0, 1.5 LPM), inclination angle (25°, 30°, 35°, 40°, 45°), volume concentration (0%, 0.1%, 0.2%, 0.3%, 0.4%), and intensity (400 W/m2). The 3D numerical model having similar geometry as of actual flat plate collector was modeled using Fluents 15.0. The SST turbulence model was used to capture the chaotic changes in the velocity, temperature, and pressure fields. The experimental findings revealed 79.74% improvement in instantaneous efficiency at 0.4% vol., 1.5 LPM, 45° inclination angle, and 400 W/m2 intensity. The maximum deviation between the experimental and numerically calculated outlet and inlet temperature difference (ΔT) was 3.5% using a hybrid nanofluid. When numerical data are compared, instantaneous efficiency and heat gain both deviate by 2.8% and 2.9% from experimental values. Because of the numerical simulation analysis, it is possible to observe the temperature and flow pattern in flat plate collectors using nanofluids under a set of operating conditions, which would not be possible without the simulation.
Subject(s)
Nanoparticles , Solar Energy , Sunlight , Temperature , Hot Temperature , WaterABSTRACT
Cutting tool characterization plays a crucial role in understanding the behavior of machining operations. The selection of a suitable cutting material, the operating conditions for the work piece, is necessary to yield good cutting-tool life. Several pieces of research have been carried out in cutting-tool characteristics for turning operation. Only a few pieces of research have focused on correlating the vibrations and stress with wear characteristics. This research article deals with stress induced in silicon carbide tool inserts and coated tool inserts while machining SS304 steel. Since this material is much less resistant to corrosion and oxidation it is widely used in engineering applications such as cryogenics, the food industry and liquid contact surfaces. Moreover, these materials have much lower magnetic permeability so they are used as nonmagnetic engineering components which are very hard. This article focuses on the machining of SS304 by carbide tool inserts and then, the cutting forces were observed with a tool dynamometer. Using observed cutting forces, the induced stress in the lathe tool insert was determined by FEA investigation. This research also formulates an idea to predict the tool wear due to vibration. Apparently, the worn-out tool vibrates more than new tools. Using the results, the relation between stress, strain and feed rate, depth of cut and speed was found and mathematically modeled using MINI TAB. It was observed that carbide tool inserts with coating withstand better than uncoated tools while machining SS304. The results were anticipated and correlation between the machining parameters furnished the prediction of tool life and obtaining the best machining outcomes by using coated tool inserts.
ABSTRACT
Increasing global environmental problems and awareness towards the utilization of eco-friendly resources enhanced the progress of research towards the development of next-generation biodegradable and environmentally friendly material. The development of natural-based composite material has led to various advantages such as a reduction in greenhouse gases and carbon footprints. In spite of the various advantages obtained from green materials, there are also a few disadvantages, such as poor interfacial compatibility between the polymer matrix and natural reinforcements and the high hydrophilicity of composites due to the reinforcement of hydrophilic natural fibers. This review focuses on various moisture-absorbing and sound-absorbing natural fiber polymer composites along with the synopsis of preparation methods of natural fiber polymer composites. It was stated in various studies that natural fibers are durable with a long life but their moisture absorption behavior depends on various factors. Such natural fibers possess different moisture absorption behavior rates and different moisture absorption behavior. The conversion of hydrophilic fibers into hydrophobic is deemed very important in improving the mechanical, thermal, and physical properties of the natural-fiber-reinforced polymer composites. One more physical property that requires the involvement of natural fibers in place of synthetic fibers is the sound absorption behavior. Various researchers have made experiments using natural-fiber-reinforced polymer composites as sound-absorbing materials. It was found from various studies that composites with higher thickness, porosity, and density behaved as better sound-absorbing materials.
