Mechanical

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

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VIT University

School of Mechanical Engineering

Hydrogen gas stands as a renewable energy fuel for the transportation sector. The hydrogen to air ratio is an essential factor in deciding the combustion and therefore the thermal efficiency of an internal combustion engine. In this study, the mixing of hydrogen and air is considered among the four geometrical configurations. These cases are considered from the simple duct and vortex tube which induces an additional swirl inside a cylinder. The approach of the study involves the meshing and computation of mass, momentum and energy equations by finite volume method. After the convergence of results, mixture ratio is analyzed with the velocity components and vorticity variables. The ratio of hydrogen to air is found to vary between 8 and 35 among the cases considered. The desired ratio could be obtained from the combination of vortex tube and plain duct configurations. Stratification of mixture is found to be significant from the gradient of velocity components in this study. © 2021 Hydrogen Energy Publications LLC

Chennai Campus

International Journal of Hydrogen Energy

Numerical investigations of hydrogen and air mixture with vortex tube and duct combinations

Diesel engines are commonly employed for transportation and power generation. Injection of diesel into the cylinder plays a crucial role towards cycle efficiency and emission regulations. The literature overview of several parameters, such as swirl ratio, injection timing, exhaust gas recirculation, fuel temperature and combustion chamber geometry, is presented in this review work. It is suggested that Computational Fluid Dynamics (CFD) simulations inside the cylinder are useful for predicting the flow field, combustion and pollutant formation. Future directions are indicated for further research on direct injection diesel engines. © 2021 Engineers Australia.

Australian Journal of Mechanical Engineering

A review of computational studies on the effect of physical variables in direct injection diesel engines

Depletion of natural fuel resources, rising fossil fuel costs and emission have led to use of renewable energies. Use of solar energy for drying is one of the most effective methods due to its renewable nature and availability. Increasing demands for healthy food and low-cost natural foods are fulfilled by solar drying. Miscellaneous types of solar dryers have been introduced and used in several countries based on their design, working and technical performance. Design and performance of natural convection and forced convection solar driers with different configurations have been reviewed. New trends and developments in hybrid dryers are mainly focused in this article. Solar driers especially designed for drying fruits, vegetables, medicinal leafs and grains along with different types of dryers used in different parts of the world are also reviewed. The economic analysis of different driers has also been discussed in this article. © 2018 Informa UK Limited, trading as Taylor & Francis Group.

World University root node

International Journal of Ambient Energy

Solar power drying system: a comprehensive assessment on types, trends, performance and economic evaluation

Centrifugal pumps are an inevitable part of modern life, and these devices are significant consumers of electric power. In general, a pump is a mechanical device for moving a fluid from a location to the other location spatially, or from a lower altitude to a higher altitude. In the process industries, more than 90% of pump applications have been covered by centrifugal pumps as it has very few moving parts and is available in a wide range of flow rates and pressure differential. Centrifugal pumps are probably among the most often used machinery in industrial facilities as well as in common life. For technical applications selection of centrifugal pump and proper analysis of pump output parameters such as discharge head and efficiency are important factors to be considered. The performance of a centrifugal pump can be enhanced by optimizing the design of the centrifugal pump. Some design modifications related to parts of a centrifugal pump such as nose-cap improve the performance. They behave similar to a nozzle which increases the velocity of the fluid at the entry of the impeller. In this paper, the various profile of the nose-cap such as linear, quadratic, exponential and power equation curves are derived. Among all these curves the best profile is fabricated and the nozzle is threaded to the shaft. The CFD analysis for the profile is also performed. It is concluded that the overall efficiency of the pump is on an average 2–3% higher for all the three nose-caps when compared to the pump without nose-cap. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Lecture Notes in Mechanical Engineering

Investigation on Centrifugal Pump Performance for Various Nose-Cap Geometries

This paper reports on the numerical investigation of assisting and opposing mixed convection flows and heat transfer performance of nanofluids in a cubical enclosure under turbulent conditions. The enclosure side wall consists of a partially heated heat source and the nanofluid is pumped into the enclosure through the inlet port. A three-dimensional, turbulent two-phase mixture model is developed to investigate the thermal performance of nanofluids by considering the effects of Brownian motion and thermophoresis. The base fluid is considered as water into which different nanoparticles such as aluminum oxide (Al2O3), copper (Cu) and silver (Ag) are dispersed for different particle volume fractions (ϕ) varied from 0% to 4%. The Richardson number (Ri) and Reynolds number (Re) are varied between 0.01 ≤ Ri ≤ 10 and 3.1 × 103 ≤ Re ≤ 105 and the Grashof number (Gr) is maintained at a constant value of 108. The nanoparticles are considered as monodispersed spherical particles with a uniform diameter of 100 nm. The results indicate that the temperature and turbulent kinetic energy distributions for opposing flows are higher than assisting flows. It also found that the average heat transfer rate increases with decrease in Richardson number and increase in volume fraction for both assisting and opposing flows. The effects of Brownian motion and thermophoresis are more significant in assisting flows than opposing flows. © 2020 Elsevier B.V.

Powder Technology

Effects of nanoparticle dispersion on turbulent mixed convection ows in cubical enclosure considering Brownian motion and thermophoresis

As in the current industrial process, mixing is an essential process for various streams of application in engineering fields. The aim of this paper is to predict flow behaviour of the mixing process in mixing tank with the Rushton impeller and find out the best suitable design that creates required turbulence for producing a better degree of homogeneity in mixing. The rotation of the impeller is modelled using MRF in a single-phase medium treating the walls with a no-slip boundary. The mixing characteristics of single and multiple impellers are investigated by varying the impeller speeds and the results of velocity and pressure contours are compared to identify the best impeller with enhanced mixing. © 2021 Institute of Physics Publishing. All rights reserved.

Fulltext

Journal of Physics: Conference Series

CFD simulation of turbulent flow behaviour in a mixing reactor with Rushton impeller

Harmonic drives are power transmitting devices with high torque and precision. They are used in many applications for their advantage of providing high torque ratio and reduced backlash, thereby reducing the power loss in the drive. The primary objective of this project is to modify the design of the harmonic dives by introducing harmonic teeth instead of existing straight teeth. The harmonic drives were modeled using SolidWorks. Three incremental loads are applied on a tooth of each harmonic drives and the stress developed on the tooth was found out using structural analysis in ANSYS. The results showed that the stress generated on the helical tooth of the flex spline was less compared with that of the stress developed on the straight tooth. There was an increase in the stress developed as the force acting on the tooth increased. © 2021, Springer Nature Singapore Pte Ltd.

Design and Analysis of Helical Teeth Harmonic Drive

The research work has focused on identifying the influence of pulsed gas metal arc welding (PGMAW) parameters on the austenitic stainless steel (ASS) weld bead on high-strength low-alloy (HSLA) steel plate. The effect of pulse parameters such as dimensionless factor (ϕ), mean current (Im), and heat input (Ω) has been analyzed on the thermal behavior of weld, weld pool geometry, and the weld bead microstructure. The influence of ϕ on the thermal and metal transfer behaviors has been also examined to produce the desired weld bead quality. The optimized pulse parameters such as Im (160–230 A), Ω (6.5–11.2 kJ/cm), ϕ (0.05–0.25), and welding speed (S) (15–25 cm/min) have been considered to perform the experiment. The microstructural evaluation of the weld bead was carried out by an optical microscope. The enhanced Im from 160 A to 230 A considerably increased the amount of temperature received by the weld pool (QT) from 4525 to 6525 J/S. The results also depicted that the increase of ϕ from 0.05 to 0.25 predominantly reduced the width of the weld bead (Wb) from 15 to 13.5 mm, depth of penetration (Pd) from 3.5 to 2.5 mm, and area of fusion (Af) from 40 to 30 mm2, respectively. It is also found that the formation of fine-grain microstructure in the weld deposit primarily happened due to the effect of thermal behaviors such as QT, transfer of heat content from filler to weld pool (Qf), and characteristics of filler metal transfer to the weld deposition. © 2020, The Indian Institute of Metals - IIM.

Department of Manufacturing Engineering

Vellore Campus

Transactions of the Indian Institute of Metals

Thermal and Weld Bead Characteristics of Bead-on-Plate PGMA Welding of Dissimilar ASS Bead on HSLA Plate

Friction stir welding (FSW) is a relatively new solid-state joining process. This joining technique is energy efficient, environment friendly, and versatile. In particular, it can be used to join high-strength aerospace aluminum alloys and other metallic alloys that are hard to weld by conventional fusion welding. FSW is considered to be the most significant development in metal joining in a decade. Recently, friction stir processing (FSP) was developed for micro structural modification of metallic materials. In this review article, the current state of understanding and development of the FSW and FSP tool process parameters are addressed. To identify the tool parameters, it is necessary to monitor the tool condition. Diagnosis the recognition of the nature and cause of a certain phenomenon. It is generally used to determine cause and effect of a problem. Machine fault diagnosis, a field of finding faults arising in machines. To identify the most probable faults leading to failure, many methods are used for data collection, including vibration monitoring, Thermal imaging, Oil particle analysis etc. Then these data’s are processed using methods like spectral analysis, wavelet analysis, wavelet transform, Short term fourier transform, high resolution spectral analysis, waveform analysis etc. The results of this analysis are used in a root cause failure analysis in order to determine the original cause of the fault. This paper presents a brief review about one such application known as machine learning for the friction stir welding tool monitoring.

Friction Stir Welding Tool Condition Prediction Using Vibrational Analysis Through Machine Learning - A Review

Carbide cutting tools form an essential part of the manufacturing industry. A cutting tool, as the name suggests, is a cutting aid, generally harder than the workpiece material which is used for cutting the workpiece material and removing excess material in the form of chips. Any deviation in its condition affects the complete material removal process with respect to quality, accuracy, and durability. Thus, a condition supervision system for fault identification has turned out to be a key priority. The current era of Machine Learning (ML) stimulates the induction of classifier training for tool condition. In this paper, a study on carbide cutting tools is presented during a turning operation carried out on a simple lathe machine. The signature analysis of vibration generated due to the change in the carbide tool condition is carried out. Finally, a Boosted Trees Ensemble is deployed for training of various tool conditions. © 2021 Totem Publisher, Inc.