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

Cryogenic machining is a sustainable manufacturing approach; it eliminates coolant disposal cost, health problems compared to the conventional flood cooling. The present study investigates the multiple response optimisation of turning process while machining AISI 17-4 PH stainless steel under the cryogenic environment (jetting of liquid nitrogen at -196°C at the rake face of the tool) by using Taguchi-based grey relational analysis. The optimum levels of the machining parameters are cutting speed at 120.89 m/min, feed rate at 0.048 mm/rev, depth of cut 0.4 mm and physical vapour deposition (PVD) AlTiN coated tungsten carbide (WC). Taguchi-based grey relational analysis method reduced the cutting forces by 7.75%, improved the surface finish by 55.87%, and increased the material removal rate (MRR) by 154.76% and 25% increased the tool flank wear in cryogenic turning process. From the analysis of variance, it was identified that feed rate is the most influenced process parameter on turning performance characteristics. Copyright © 2017 Inderscience Enterprises Ltd.

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International Journal of Machining and Machinability of Materials

Multi-objective optimisation of cryogenic turning process using Taguchi-based grey relational analysis

The present work investigates an experimental study of thermally enhanced machining of nickel-based superalloy Inconel 718 using uncoated tungsten carbide inserts. An inexpensive flame heating technique using an oxyacetylene flame is used as a heat source for thermal enhancement of workpiece. The effects of cutting parameters like cutting speed, feed rate, depth of cut and temperature of workpiece on the performance characteristics like surface roughness, tool wear and material removal rate were studied. A L27 orthogonal array with four parameters and three levels was adopted for experimental design. Multi response optimisation was done using grey relation analysis to simultaneously minimise surface roughness, tool wear and to maximise material removal rate. It was observed that at cutting speed at 85.21 m/min, feed rate at 0.048 m/min, depth of cut at 0.6 mm and workpiece temperature at 600°C were optimal cutting parameters. It is clearly shown that the above performance characteristics in thermally enhanced machining can be improved effectively through this approach. Copyright © 2017 Inderscience Enterprises Ltd.

Multi objective optimisation of thermally enhanced machining parameters of Inconel 718 using grey relational analysis

IOP Conference Series: Materials Science and Engineering

Experimental investigation on mixed refrigerant cryocooler operating at 70 K for cooling high temperature superconductors

The 7th International Conference of Asian Society for Precision Engineering {\ldots}

A novel approach in deep hole drilling of Inconel 718

We discuss the role of discrete mass conservation on the simulations of thermobuoyant flows in enclosures through a detailed numerical investigation in the Boussinesq and non-Boussinesq regimes. Employing a low Mach number formulation in conjunction with a pressure-based approach, we devise two unified algorithms that are capable of handling a wide range of temperature differences. These algorithms can be broadly categorized as discretely conservative and discretely consistent algorithms based on their implementation. While the discretely conservative algorithm computes the density by solving the mass conservation equation in each control volume (along with other conservation laws), the discretely consistent algorithm employs the algebraic equation of state to evaluate the local density. We show that the discretely consistent algorithm is prone to a discrete mass conservation error which can be detrimental to numerical stability in steady non-Boussinesq flows and can significantly influence the computed flowfield in case of unsteady non-Boussinesq convection. We also show that although the discretely conservative algorithm does not satisfy the discrete equation of state it introduces no significant errors in thermodynamic pressure for closed systems. Several numerical experiments over a range of temperature differences, Rayleigh and Prandtl numbers are carried out and the results whilst supporting the theoretical arguments also indicate that the discrete mass conservation errors are strongly linked respectively to numerical stability and solution accuracy in steady and unsteady non-Boussinesq flows. © 2016 Elsevier Ltd

International Journal of Heat and Mass Transfer

On the role of discrete mass conservation for non-Boussinesq flow simulations in enclosures

In machining process, friction between the chip-tool interface and the heat generation due to shearing action are important issues that govern the machining forces, tool life and surface quality of the product. Efficient cooling and lubrication can reduce the high amount of heat generated during machining. The cooling and lubrication depend on the wetting behavior of metal working fluid (MWF) on the tool surface. However, the relation between the key parameters which affect the MWF's wettability behavior on the cutting tool surface are not studied much, especially for the machining process. In this paper, an attempt has been made to understand the correlation between the spreading behavior, surface tension and surface energy of nano-Al2O3 based fluid added with different surfactants, on tungsten carbide (WC) cutting inserts (Ti-Al-N coated and uncoated) and Inconel 718. Further, machining experiments have been conducted using the nanofluid (NF) under minimum quantity cooling and lubrication (MQCL) mode. The results showed that the spreading parameter of NF varies linearly with the surface tension on cutting tool surfaces. The spreading parameter has been found to be more reliable, and a relevant parameter for describing the wetting behavior of NF on the tool surfaces. The machining results obtained in this study are explained in terms of the spreading coefficient, and the best wetting behavior has been observed when the non-ionic surfactant added NF is used on the uncoated tool surface. Consequently, machining experiments with Inconel 718 using the aforementioned NF showed a reduction in coefficient of friction, tool wear, and chip curling radius. © 2017 Elsevier B.V.

Journal of Materials Processing Technology

Spreadability studies of metal working fluids on tool surface and its impact on minimum amount cooling and lubrication turning

Laser-based Diagnostics and Numerical Simulations of Syngas Combustion in a Trapped Vortex Combustor

Composite materials are novel inventions of material science which are often used as viable solutions in many technologically challenging situations like aero-space and satellite applications, because of their well known superior mechanical properties. The challenge which these materials always pose to the thermal designers, is knowledge of their thermal properties, effective directional thermal conductivity being one of them as this is critical in the design of systems employing these materials. The present work aims at developing a novel experimental technique for the simultaneous estimation of principal thermal conductivities of a layered honeycomb composite widely used in aerospace structures. A new standard test material exhibiting structural anisotropy with respect to thermal transport is first conceptualised, designed and fabricated. A full scale direct numerical simulation is performed on the standard test material to understand the thermal transport process in it and determine its principal thermal conductivities. Following this, carefully designed experiments are performed on the standard test material in simulated space environment (inside a vacuum chamber) and its principal thermal conductivities are estimated using the developed inverse methodology based on a synergistic combination of artificial neural network (ANN) and genetic algorithm (GA). Experimentally obtained thermal conductivities are compared with those obtained from full scale numerical simulations. A close agreement between the experimentally and numerically estimated thermal conductivities is observed, validating the technique and establishing the possibility of use of a full scale numerical model as an alternate and standalone approach for estimation of thermal conductivities of structured integral composites. Finally, a layered honeycomb composite having carbon fiber reinforced plastic (CFRP) facesheet and aluminium core actually used in satellite applications is tested and its principal thermal conductivities are estimated. Problems related to interface thermal contact conductance in case of honeycomb composites are also brought out and addressed. © 2016 Elsevier Masson SAS

International Journal of Thermal Sciences

Estimation of principal thermal conductivities of layered honeycomb composites using ANN–GA based inverse technique

This paper presents a comprehensive study of the forward kinematic problem of a newly introduced spatial parallel manipulator, namely, the 3-RPRS manipulator. The manipulator has three legs with two actuators in each, which connect a moving triangular platform to a fixed base. Three loop-closure equations are formed with the three passive joint angles in the legs, as the unknowns, which are subsequently reduced to a single univariate polynomial equation of degree 16. The coefficients of this equation are obtained as closed-form functions of the architecture parameters of the manipulator and the input joint variables. Furthermore, it is found that the polynomial has only the even-powered terms, leading to 8 pairs of solutions. One solution in each pair represents a pose on one side of the fixed base, and the other, a reflection of the same at the said base plane. The theoretical developments are illustrated via several numerical examples, one of which yields 16 real solutions, thus establishing that the obtained univariate polynomial is minimal in its degree. The results obtained are validated numerically, as well as verified against the inverse kinematics of the manipulator, thereby establishing the correctness of the formulation as well as the results. © 2017 Elsevier Ltd