Department of Mechanical Engineering

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

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Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and {\ldots}

Prediction of thermal contact conductance in conforming rough metal contacts through regeneration of surface profile

Lecture Notes in Mechanical Engineering

Preface

A parametric computational study was conducted on UWS (urea-water-solution) droplets evaporating at conditions typical of an automobile SCR (selective catalytic reduction) system. The computational model used in the present work has been validated earlier using experimental data and was found capable of predicting the evaporation behaviour of UWS droplets. The ambient temperatures considered in the present study ranged from 423 K to 873 K and the free-stream gas velocities used were between 1 m/s and 100 m/s. The droplets were injected perpendicular to the free-stream and the droplet diameter, as well as its position, was tracked with time. The initial diameters of the droplets investigated ranged between 10 and 200 microns. A rapid mixing (RM) model was employed for the liquid phase in order to reduce the computational costs and the droplet evaporation model was based on the vaporization model proposed by Abramzon and Sirignano. The effect of the ambient gas, on the vaporization rate of the droplet, was also investigated in the present work. The governing equations, used in the computational model, were solved numerically using MATLAB and the results on the vaporization behaviour of the UWS droplets are presented. © 2021 ICLASS 2021 - 15th Triennial International Conference on Liquid Atomization and Spray Systems. All Rights Reserved.

International Conference on Liquid Atomization and Spray Systems (ICLASS)

A Parametric Study of the Evaporation Behaviour of UWS Droplets

The present work showcases simulation of a turbulent diffusion flame for validation of the turbulencechemistry interaction approach. The turbulence model employed was k-ε with the model constants determined from simulation of a non-reacting turbulent jet. The jet decay rate and spread rate were determined with excellent accuracy when compared with experimental measurements. The non-dimensional velocity profiles also show a significant agreement except at radial locations far away from the axial centreline. Simulations of the DLR-A flame using a single step infinite rate chemistry assumption were carried out with the model constants thus determined. The reaction rates are determined based on the mixed-is-combusted approach where the mixture fraction, a conserved scalar quantity is obtained by the solution of a governing equation. In addition the mean velocity, species mass fractions and temperature profiles in the axial and radial direction are compared with experimental data. The axial profiles show very good agreement while the radial profiles show deviations due to the assumption of equal binary mass diffusivities for all species and unity Lewis number, which is a suitable approximation for turbulent gaseous flows. In addition, the temperatures are overpredicted by close to 15% due to the single-step infinite rate chemistry approach adopted in this study. The validation serves to justify the choice of the combustion model for the simulation of turbulent reacting flows. This is especially significant due to the lesser computational effort involved in obtaining the rates of the reaction for a turbulent diffusion flame. © 2021, Begell House Inc. All rights reserved.

International Symposium on Advances in Computational Heat Transfer

Rans based numerical simulations of turbulent diffusion flame using openfoam®

The article discusses the structure and model of a robotic system for the rehabilitation of the lower limbs based on a passive orthosis in the form of a serial RRRR mechanism and an active parallel 3-PRRR mechanism. Effective numerical methods and algorithms were developed and tested that made it possible to determine the minimum geometric parameters of the active parallel mechanism that ensure the movement of the passive orthosis within the workspace under clinical data when simulating walking. The structure is proposed. The basis parameters for the rehabilitation system design are investigated. To implement the developed methods, an effective algorithm, software package, and visualization system for exported three-dimensional workspaces in STL format were synthesized. The results of mathematical modeling and analysis of the results are given. © 2021, CISM International Centre for Mechanical Sciences.

CISM International Centre for Mechanical Sciences, Courses and Lectures

Determination of the Geometric Parameters of a Parallel-Serial Rehabilitation Robot Based on Clinical Data

This paper focuses its attention on the mechanical design of autonomous agricultural robots used for the purpose of harvesting fruits in plantations. The paper analysis the present mechanical designs, identifies the research gaps and proposes a novel design of a fruit plucking robot. A design consisting of a four wheeled mobile base, a manipulator and an end-effector has been proposed. An open-chain rotary-rotary-prismatic (RRP) manipulator attached to the mobile base and having two additional active rotary joints at the end-effector at the free-end has been designed. A hose has been provided to transfer fruits from the tree to the basket. The chassis of the mobile base is equipped with four solid rubber power (motorized) wheels controlled by skid steering method and a detachable basket for collecting fruits. A counterweight mechanism has been designed to provide static stability. The paper addresses the issues present in the current mechanical designs with a brief discussion on the system architecture. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Mechanisms and Machine Science

A Novel Design for an Autonomous Mobile Agricultural Fruit Harvesting Robot

Response surface methodology (RSM) is used for mathematical modeling of friction stir welding parameters for joining AA6061 composite material. Characteristics of joints were examined through response characteristics such as ultimate tensile strength (UTS) and microhardness (HV) using RSM. Microstructure examination was carried out using optical microscopy, scanning electron microscopy and electron backscattered diffraction, and results exhibit variation in the grain size diameter. Specifically, lower nugget exhibits fine grains with maximum hardness compared to middle nugget and upper nugget. Analysis of variance (ANOVA) results indicate good match between actual values and predicted values with R2 of 0.91 and 0.96, respectively, for UTS and HV, and better joint efficiency of 90% is obtained. © 2021, The Indian Institute of Metals - IIM.

Transactions of the Indian Institute of Metals

Analysis of the Effect of Friction Stir Welding Parameters on Characteristics of AA6061 Composites using Response Surface Methodology

Selective laser melting (SLM) is an emerging additive manufacturing (AM) technology for fabrication of complex lightweight components along with improved mechanical properties. However, the properties are highly influenced by the continual heating and cooling during deposition, variation in local temperature, size, and shape of melt pool, and solidification growth rate. Therefore, postprocessing is very often required to control various properties of additive manufactured components. The present work investigates the influence of various postprocessing methods such as heat treatment and electric discharge alloying (EDA) on ambient and elevated temperature wear behavior of selective laser melted AlSi10Mg alloy and compared with its tribological behavior with cast AlSi10Mg. The dry wear tests were conducted using a pin on disk (POD) tribometer with EN-31 as counter body. The EDA treated SLM AlSi10Mg showed the least wear-rate and coefficient of friction (COF) at both ambient and elevated temperatures (1.05×10-4 mm3/Nm and 0.434 and 3.12× 10-5 mm3/Nm and 0.531, respectively) due to its higher hardness (189.8 HV) as compared with other samples. The wear-rate and COF of cast specimen are found to be highest among all specimens at both ambient and elevated temperatures (1.34 ×10-4 mm3/Nm and 0.528 and 4.49× 10-5 mm3/Nm and 0.724, respectively). Lower wear-rate and higher COF are observed at elevated temperature due to the excessive formation of wear-resistant oxides (Al2O3, SiO2, and MgO) and glaze layers for all samples compared with ambient temperature wear behaviors of its counterparts. Abrasive wear, adhesive wear, oxidation wear, and surface delamination are the prominent wear mechanisms observed for ambient and elevated temperatures for all the specimens. Copyright © 2021 by ASME.

Journal of Tribology

Effect of heat treatment and electric discharge alloying on the tribological performance of selective laser melted Alsi10mg

Fabrication of deep holes (depth to diameter ratio >10) using electrical discharge drilling (EDD) has gained momentum in the areas of aerospace, automotive and biomedical industries. However, formation of recirculation zones in flushing channel causes accumulation of debris particles at higher depths of drilling. This leads to secondary discharges within the flushing channel resulting in excessive tool wear, dimensional inaccuracy and hole tapering. The present paper proposes a novel tool geometry having orifices at the bottom end of tool electrode with an aim to improve debris evacuation. The effectiveness of proposed method is established through CFD simulations and experiments. © 2021 CIRP

CIRP Annals

Novel EDM deep hole drilling strategy using tubular electrode with orifice

Inconel 625 is a solid-solution strengthened nickel-based superalloy that found widespread usage in aerospace, marine, and nuclear applications due to its outstanding mechanical properties. Thus in the current study, the machining performance of Inconel 625 under nano-minimum quantity lubrication (nMQL) environment is investigated. Graphene nanoparticles were selected to enrich the physicochemical properties of coconut oil as a cutting fluid. Experiments were conducted using AlTiN PVD coated carbide cutting tool inserts under stable nano-cutting fluids of various concentrations and at different levels of cutting speed, feed, and depth of cut. The experiments were conducted according to Taguchi’s L16 orthogonal design. Surface roughness, tool flank wear, and material removal rate were selected as responses to study the effects of cooling conditions and machining parameters. The turning process performance was optimized by the grey relational multi-objective optimization method. Cutting speed of 80 m/min, feed of 0.05 mm/rev, depth of cut of 0.8 mm, and cooling condition with 0.50 wt. % graphene nanofluid MQL was established as the optimal machining conditions. Analysis of variance (ANOVA) was performed to identify the importance of input parameters on machining performance and the results indicate that feed and cooling conditions are the most influential parameters. Also, the tool wear mechanisms and chip morphology were identified and analyzed using SEM and EDS to understand the cutting tool performance under each cooling condition by considering the optimal machining parameters. The lesser tool wear and better chip morphology were obtained under 0.50 wt. % graphene nano-cutting fluid environment. © 2021, King Fahd University of Petroleum & Minerals.