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.

&nbsp;

IIT Palakkad

Present study investigates the effect of the mixture equivalence ratio on the heat transfer characteristics of impinging premixed methane-air flame jets of tube burners equipped with twisted tape inserts. The induced swirl flow enhances the mixing process and improves the flame stability limits. The flame jet with mixture Reynolds number of 800 and burner to plate spacing of four times burner diameter is chosen based on the flame stability range. The heat transfer characteristics of non-swirling flame jet are compared with the swirling flame jets for various mixture compositions. Swirl flow is achieved with twisted tape inserts having twist ratios of 2, 3.2, 4.5 and 7.5. Twisted tape inserts resulted asymmetric flame. The flame shape is found to be highly influencing the heat transfer from the flame jet to the target surface. Better heat transfer distribution is achieved with stoichiometric mixture. However, the rich mixture produces more uniform heat flux distribution. Best thermal performance is observed for twisted tape with twist ratio of 7.5. The present study helps in better understanding and optimum design of the flame jet impingement heat transfer equipment. © 2016 Elsevier Masson SAS

World University root node

International Journal of Thermal Sciences

Effect of mixture composition on heat transfer characteristics of impinging methane-air flame jets of tube burners equipped with twisted tapes

Composition, structure and properties of the products of self-propagating high-temperature synthesis (SHS) are characterised by some distinctive features. High heating rate, fast cooling after rapid completion of the reactions and steep temperature gradients make SHS very effective in producing in situ composites with ceramic reinforcements. In the present work, hardfacing of AISI304 substrates has been done by fabricating a hard ternary ceramic matrix composite layer of Al2O3–TiB2–TiN by laser surface treatment at different scan speeds. The formation of the surface layer is due to laser-triggered SHS followed by laser melting. A mixture of Al, TiO2 and hBN has been used as a precursor for the SHS reaction. The study of the microstructure of the as-fabricated composite layer reveals the co-existence of TiB2 and TiN phases in the nanometric size range in Al2O3 matrix. The presence of all the phases has been confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The average grain sizes were calculated for the reinforcing phases and found to be 36 and 66 nm for TiB2 and TiN, respectively, for the ceramic layer fabricated with a scan speed of 10 mm s−1, whereas 21 and 53 nm have been observed for TiB2 and TiN, respectively, for the ceramic layer fabricated with the scan speed of 5 mm s−1. The understanding of the chemical synthesis in the SHS reaction mentioned here and the process of development of the reinforced composite in the fabrication of the hardfaced layer over steel surface will be immensely helpful in the discernment of the mechanical properties and, thus, finding the target area for the usage of this product. The virtues of the process and formation of the hard composite are reflected well in the microhardness achieved in the fabricated layers, as it is significantly higher than that of the substrate (AISI304 steel). In addition, indentation with a Berkovich tip in a nano-indentation set-up helped in further evaluation of the composite’s hardness and elastic modulus. The property spectrum of the composite, as reported here, indicates its suitability in various wear-intensive applications. © 2017 Institute of Materials Finishing.

Transactions of the Institute of Metal Finishing

Hardfacing of AISI304 steel: fabrication of oxide-boride-nitride ceramic matrix composite layer by laser-assisted high temperature chemical reaction

In this paper, a highly non-linear model with six degrees of freedom (DOF) is used for the manoeuvring and depth control of an autonomous underwater vehicle (AUV). A simplified scheme to design a conventional fuzzy logic controller known as robust Proportional Derivative (PD)-like Fuzzy Controller (PD-FZ) is designed separately for diving and steering subsystems of an AUV and then applied for combined steering, diving and speed control functions. Simulation results are shown by using the slender form of the Naval Post-Graduate School (NPS, Monterey, CA) AUV. Results of simulation studies using a nonlinear AUV dynamics are presented under the presence of any bounded ocean currents or wave disturbances and results show that proposed controller gives robust performance against these disturbances and modeling nonlinearity. Waypoint acquisition based on line of sight guidance is used to achieve path tracking. © 2017 IOS Press and the authors. All rights reserved.

Journal of Intelligent and Fuzzy Systems

Robust proportional derivative (PD)-like fuzzy control designs for diving and steering planes control of an autonomous underwater vehicle

Under higher cutting conditions, machining of 17-4 precipitation hardenable stainless steel (PH SS) is a difficult task due to the high cutting temperatures as well as accumulation of chips at the machining zone, which causes tool damage and impairment of machined surface finish. Cryogenic machining is an efficient, eco-friendly manufacturing process. In the current work, cutting temperature, tool wear (flank wear (Vb) and rake wear), chip morphology, and surface integrity (surface topography, surface finish (Ra), white layer thickness (WLT)) were considered as investigative machinability characteristics under the cryogenic (liquid nitrogen), minimum quantity lubrication (MQL), wet and dry environments at varying cutting velocities while machining 17-4 PH SS. The results show that the maximum cutting temperature drop found in cryogenic machining was 72%, 62%, and 61%, respectively, in contrast to dry, wet, and MQL machining conditions. Similarly, the maximum tool wear reduction was found to be 60%, 55%, and 50% in cryogenic machining over the dry, wet, and MQL machining conditions, respectively. Among all the machining environments, better surface integrity was obtained by cryogenic machining, which could produce the functionally superior products. © 2017 Taylor & Francis.

Materials and Manufacturing Processes

Machinability studies on 17-4 PH stainless steel under cryogenic cooling environment

Machining of 17-4 Precipitation Hardenable Stainless Steel (PH SS) is one of the difficult tasks because of its high cutting temperatures. Conventional cutting fluids are used to overcome the high cutting temperatures, but these are not acceptable from the health and environmental sustainable points of view. Cryogenic cooling is one of the potential techniques to overcome such problems. In the current work, comparison is made of cryogenic turning results, such as tool flank wear, cutting forces (feed force, main cutting force), cutting temperature, chip morphology and surface integrity characteristics with wet machining during machining of heat-treated 17-4 PH SS. The result showed that in cryogenic machining, a maximum of 53%, 78%, 35% and 16% reductions was observed in tool flank wear, cutting temperature, surface roughness and cutting force, respectively, when compared with wet machining. It was also evident from the experimental results that cryogenic machining significantly improved the machining performance and product quality even at high feed rates. © 2017 Taylor & Francis.

Influence of cryogenic coolant on turning performance characteristics: A comparison with wet machining

We estimate the equilibrium size distribution of cholesterol rich micro-domains on a lipid bilayer by solving Smoluchowski equation for coagulation and fragmentation. Towards this aim, we first derive the coagulation kernels based on the diffusion behaviour of domains moving in a two dimensional membrane sheet, as this represents the reality better. We incorporate three different diffusion scenarios of domain diffusion into our coagulation kernel. Subsequently, we investigate the influence of the parameters in our model on the coagulation and fragmentation behaviour. The observed behaviours of the coagulation and fragmentation kernels are also manifested in the equilibrium domain size distribution and its first moment. Finally, considering the liquid domains diffusing in a supported lipid bilayer, we fit the equilibrium domain size distribution to a benchmark solution. © 2016 Elsevier B.V.

Physica B: Condensed Matter

Diffusion mediated coagulation and fragmentation based study of domain formation in lipid bilayer membrane

This work presents the first non-intrusive quantitative measurements of [OH] and temperature in H2/CO syngas/air counterflow diffusion flames as a function of H2:CO ratio and local strain rates. The H2:CO ratio was varied as 8:32, 20:20 and 32:8 volumetrically maintaining a constant dilution of 58% N2and 2% CH4. The local strain rates ranged from 35 s−1to 1180 s−1. Peak temperature and [OH] were observed to increase with increasing H2:CO ratio in the syngas fuel. Peak [OH] displayed a non-monotonous function of strain rate for all compositions of syngas. The measurements were used for rigorous assessment of five H2/CO chemical kinetic mechanisms from the literature designated as M1 to M5. The M1 mechanism was found to provide the best overall match with experiments, however, significant discrepancies were observed in comparison between measurements and [OH] predictions for low H2:CO ratio at low strain rates and for higher H2:CO ratio at high strain rates. While sensitivity analyses and reaction rate analyses identified H + O2+ M ⇔ HO2+ M as one of the key reactions affecting the [OH] at low strain rates. However, at higher strain rates, chain-branching reactions such as H + O2⇔ OH + O and O + H2⇔ OH + H were found to be important at higher strain rates. The reaction sensitivity towards [OH] was found to change from negative to positive as the strain was increased for medium and high H2:CO ratios. A reduction in the Arrhenius co-efficient for the third body reactions H + O2+ M ⇔ HO2+ M and H + OH + M ⇔ H2O + M showed significant improvements in the predictions of [OH] and extinction limits for non-premixed flames while showing good agreement with the laminar flame speed data available in the literature.

Fuel

Quantitative OH measurements and numerical investigation of H2/CO kinetics in syngas-air counterflow diffusion flames

Several designs of In-pipe inspection robots (IPIR) have been proposed in the literature to solve the problems related with inspection of these complicated internal geometries. Designing of an in-pipe inspection robot (IPIR) is a difficult task and hence the designer must take care of the design issues. Authors have already proposed a new design for in pipe inspection robot. This research work presents investigations into driving torque variation during its use in a full running pipe to overcome the drag caused by the flowing viscous fluid. This proposed model is a screw driver type wall press adaptable wheeled In-pipe inspection robot. It is able to move through vertical, inclined and horizontal pipes and it can easily pass through elbow of a pipe line. This model comprises of three modules- rotor, stator and control unit. The Rotor module has three wheels mounted on the outer periphery with a helix angle of 18o. Wheels of rotor follow the helical path on the internal surface of pipe line and move in the longitudinal direction inside the pipe. A mathematical model is proposed to estimate the driving torque required by the proposed robot. Driving torque is a function of forces coming on the robot due its motion inside the pipe and drag force generated due to flowing media. The torque on motor varies with change in viscosity of flowing fluid inside the pipe, speed of fluid and pipe inclination. The form and skin drag forces are predicted using computational fluid dynamic approach through ANSYS fluent software and robot driving torque variation is studied under full running pipe. © 2017 Association for Computing Machinery.

ACM International Conference Proceeding Series

Prediction of torque variations in a pipe inspection robot through computational fluid dynamics

is paper addresses a task-space trajectory control of an underwater vehicle-manipulator system (UVMS) employed for interactive underwater tasks. .e robust task-space tracking control is achieved by designing a non-singular fast terminal sliding mode controller (NFTSMC) with disturbance estimator and demonstrated on a planar underwater vehicle with serial two link manipulator arm a.ached to it. .e proposed NFTSMC integrates a non-singular fast terminal sliding mode controller (NFTSMC) with a non-linear disturbance observer. This combination not only assures €nite and faster convergence of the systems states to the equilibrium from anywhere in the phase-plane but also overcomes the problem of singularity associated with conventional terminal sliding mode controller (TSMC). In addition to this, because of the disturbance observer augmented in the proposed control law, the overall stability of the closed-loop system is enhanced to a great extent. .e feasibility of the proposed NFTSMC is con€rmed by performing extensive numerical simulation on the UVMS for tracking a given pre-de€ned task space trajectory under the in.uence of parameter uncertainties, ocean current and measurement sensor noises.

Robust non-singular fast terminal sliding mode task-space position tracking control of an underwater vehicle-manipulator system

In the present work, the development of a general purpose, indigenous computational fluid dynamics code, ANUPRAVAHA, has been described for simulations of three-dimensional multi-physics problems. The code solves the governing fluid flow and heat transfer equations in a collocated, cell-centered, finite-volume framework, independent of the grid topology. The equations are discretised and solved in an implicit segregated manner using a fractional step approach. The momentum equations cast in a conservative form are linearized using Picard linearization and solved for auxiliary momenta at the cell centers. A new gradient reconstruction approach which is consistent and interpolation-free using a compact stencil is also employed for centroidal gradient computations. Time accurate simulations for unsteady problems are guaranteed using a three-point backward differencing scheme which gives second-order temporal accuracy. Governing equations for scalar quantities such as temperature (energy), concentration (species), volume fraction and turbulence quantities (such as kinetic energy and specific dissipation) are cast in a conservative transport form and discretised akin to the momentum equations. Several two-equation models using eddy-viscosity hypothesis have been implemented for turbulent flows. The pressure is then obtained by solving a Poisson equation obtained by enforcing the divergence condition. A novel generic momentum interpolation approach is applied to ensure proper pressure-velocity coupling, in the presence of large body forces and singular interfacial forces even on hybrid grids. While the solver is primarily devised to handle incompressible flows, the methodology has also been extended to weakly compressible flows, typical of non-Boussinesq convection and radiation, using a low Mach number formulation (Paolucci [1982]). The developed solver has been validated for simulating various multi-physics problems like conjugate heat transfer; droplet rising, falling and splashing; radiative heat transfer problems coupled with fluid flow and turbulent flows along with heat transfer. © 2017, Begell House Inc. All Rights Reserved.