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.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

In this paper, a double-diffusive mixed convection flow in an enclosed cavity with the effects of Soret number (Sr) and Joule’s heating parameter (J) is presented. Finite volume approach-based differed quadratic upstream interpolation for convective kinematics (QUICK) scheme and central difference scheme are used to resolve the respective convective and diffusive fluxes. The results are presented in terms of temperature, concentration and stream line contours by varying the buoyancy ratio (−100 ≤ N ≤ 100), Soret number (Sr = 0 and 1) and Joules number (J = 0 and 1). The present results are validated with the reported literature. Results show that the temperature is uniformly distributed with the absence of Soret number and a bulk fluid diffusion takes place inside the cavity once the Soret effect is induced. The effects of Joules heating on average Nu and Sh are negligible for Sr = 0, and it has a significant variation with Soret number. © 2021, Springer Nature Singapore Pte Ltd.

Department of Thermal and Energy Engineering

School of Mechanical Engineering

Vellore Campus

World University root node

Lecture Notes in Mechanical Engineering

Effects of Joules Heating and Soret Number on Double-Diffusive Mixed Convection Flow in an Enclosed Square Cavity

The fabrication or repairing of aircraft components made of Hastelloy X to be resolved using an arc welding technique. In this study, Hastelloy X was joint with ERNiCrCoMo-1 filler by pulsed current gas tungsten arc (PCGTA) welding. The high temperature tensile property of the weldment has been evaluated at three different temperatures such as 700 °C, 800 °C and 900 °C. The tensile properties such as yield strength (294, 259 and 205 MPa), ultimate tensile strength (475, 396 and 245 MPa) and percentage of elongation or ductility (17, 14 and 11 %) follows the similar trend with temperature at 700 °C, 800 °C and 900 °C respectively. It revealed the values of all the properties are decreased as the temperature increased. The lowest strength was evaluated for weldment at 900 °C. The high temperature tensile test also revealed that the fracture of weldments for all three conditions is found at the weld centre (WC). Even though, the failure happened at WC, the high temperature tensile strength of the weldments revealed that values are more or less equal to the base metal (Hastelloy X) values at 700 °C, 800 °C and 900 °C. The SEM fractography has been performed to find the tensile failure mode of weldments. The ductile dimples, ductile tear ridges and lesser cleavage-facet are found in the fractured region which derives the ductile failure. © 2020SAE International. All Rights Reserved.

Department of Design and Automation

SAE Technical Papers

Study on the High Temperature Tensile Properties of Aerospace Grade Hastelloy X Joined by Pulsed Current Arc Welding

VIT Unitversity

Fuel

Effect of n-butanol fumigation on the regulated and unregulated emission characteristics of a diesel engine

This work examines the influence of post-weld heat treatment (PWHT) on the fusion zone microstructure, and mechanical properties of electron beam (EB)-welded alloy 686. Comparative studies have been made on weld microstructure and tensile properties of the weldments both in as-welded and post-welded heat-treated conditions. PWHT consists of direct aging (DA/480°C for 3 h) and solution treatment (ST, 980°C for 1 h) followed by ageing and finally, homogenizing treatment (HT, 1200°C for 1 h) followed by DA and ST. The secondary topologically closed packed (TCP) phases formation, their distribution and microsegregation characteristics are studied with the aid of scanning electron microscope (SEM) analysis. Energy-dispersive X-ray spectroscopy (EDS) is also performed to estimate the microsegregation of alloying elements in the dendritic core and interdendritic regions of the weldments. The result shows that there is no significant change in the microstructure of DA and solution-treated sample as compared to the as-welded sample. The microstructure of HT sample was entirely different from those of as-welded and other HT samples. The SEM/EDS analysis illustrates the presence of secondary TCP phases (σ, P and μ) in the as-weld, DA and ST condition, whereas HT weldments did not show the presence of TCP phases. Tensile test results show higher tensile strength in ST condition whereas homogenization samples show higher ductility compared with others. © 2019, Indian Academy of Sciences.

Department of Manufacturing Engineering

Fulltext

Sādhanā

Effect of post-weld heat treatment on the microstructure and tensile properties of electron-beam-welded 21st century nickel-based super alloy 686

The present study investigates the dissimilar weld joints between AISI 316L and Duplex 2205 stainless steel. The joints were fabricated with the Pulsed current gas tungsten arc welding with ER316L and ER309L filler wire. The weld joints were subjected to metallurgical and mechanical characterization. The macro examination and optical microstructure examination were carried out to see the defect in the weld joints and structural changes in the fusion zone. The results show that the defect free welding was achieved in the both the filler wire. The optical microstructure shows the ferritic structure in both filler wire. The strength of the weld joints was tested with the tensile test. The results indicate the fracture occurred in the base metal in both cases. © Published under licence by IOP Publishing Ltd.

IOP Conference Series: Materials Science and Engineering

Investigation on microstructure and tensile properties of dissimilar weld joints between AISI 316l and duplex 2205 stainless steel

Performance of the engine is considered to be as one of the most important factor for any automobile company. The current interest of most automotive industries circles around their vehicles fuel economy and tail pipe emissions. This paper presents a study which explores a conventional source of energy from biofuels which leads to better performance and emission characteristics and also provides an alternative fuel to diesel. The biodiesel fuel is obtained from the seeds of Polanga oil (Calophyllum Inophyllum) which are found mainly in southern coast of India. In the experiment the biodiesel is fumigated at 200C and diesel fuel was used as an ignition source. For this purpose an electronically controlled fuel fumigator was fabricated and used in this investigation. The performance and emission characteristics of the diesel engine were measured and the results were compared in presented in this paper. © IAEME Publication.

International Journal of Mechanical Engineering and Technology

Effect of fumigated biodiesel on the performance and emission characteristics of a single cylinder diesel engine

In this study, a two-dimensional steady state double-diffusive mixed convective flow in a square cavity with Soret effect is presented. The numerical investigation is considered with two different conditions, (a) top and bottom walls move with same velocity (Uo) towards right and (b) top wall moves towards right and bottom wall moves towards left with the same velocity (Uo). The left and right walls remain stationary. The top and bottom walls are adiabatic; the left wall is maintained at high temperature and concentration. The right wall is maintained at low temperature and concentration. Governing equations are solved by finite volume method using SIMPLE algorithm in association with QUICK scheme. The Prandtl number (0.71 ≤ Pr ≤ 10) is varied with different Richardson numbers (0.01 ≤ Ri ≤ 100) to analyze the streamline, temperature and concentration contours with and without Soret effect. Results are investigated using Nusselt and Sherwood numbers. The results are also validated with the existing literature. © 2017, Global Digital Central. All Rights Reserved.

Frontiers in Heat and Mass Transfer

COMPUTATIONAL INVESTIGATION OF DOUBLE-DIFFUSIVE MIXED CONVECTIVE FLOW IN AN ENCLOSED SQUARE CAVITY WITH SORET EFFECT

In this paper, the numerical investigation of double-diffusive mixed convection with magnetohydrodynamic flow in an enclosed cavity is presented. The uniform temperature and concentration are imposed along the vertical walls and the horizontal walls which are considered as insulated. The flow behaviour is analysed for two different conditions. In first case, the top wall moves towards left at a constant velocity (Uo), while the other walls remain stationary. In the second case, the top wall moves towards right with constant velocity (Uo), while the other walls remain stationary. The convective flux in the transport equations is discretized using finite volume technique with third-order deferred quadratic upwind interpolation for convection kinematics scheme at the inner nodes and the second-order central difference scheme at the outer nodes. The pressure and velocity terms are coupled by SIMPLE algorithm. The present numerical simulation is compared with the reported literature and is found to be in good agreement. The Hartmann number (1 ≤ Ha ≤ 25), Lewis number (1 ≤ Le ≤ 50) and aspect ratio (1 ≤ A ≤ 2) are varied over a wide range to analyse the non-dimensional horizontal (U) and vertical velocities (V), stream line contours, temperature and concentration gradients. The present analysis is carried out at constant Buoyancy ratio (N = 1) and Prandtl (Pr = 0.7), Richardson (Ri = 1.0), Darcy (Da = 1.0) and Reynolds (Re = 100) numbers. The effect of Ha, Le and A on the average Nusselt (Nu) and Sherwood (Sh) numbers is also presented. © 2015, King Fahd University of Petroleum & Minerals.

Arabian Journal for Science and Engineering

The Numerical Simulation of Double-Diffusive Mixed Convection Flow in a Lid-Driven Porous Cavity with Magnetohydrodynamic Effect

This paper presents the numerical study of mixed convection in a two-sided lid driven porous cavity due to temperature and concentration gradients. The top and bottom walls are stationary and insulated. The left and right walls are moving at an equal velocity (Vo) in the same direction. The temperature and concentration are kept high at the right wall and low at the left wall. The governing equations are discretized using finite volume method. The pressure-velocity coupling is performed by the SIMPLE algorithm. A third order differed QUICK scheme is applied at the inner nodes and a second order central difference scheme is used at the boundary nodes. The flow behavior and heat transfer are analyzed for different nondimensional numbers, such as, 1 × 10-4 ≤ Ri ≤ 10, 1 × 10-4 ≤ Da ≤ 0.1 and 0.7 < Pr < 10. The present numerical results are compared with the literature and are in good agreement. For the above selected nondimensional numbers, the heat and fluid flow behavior is investigated using local and average Nusselt (Nu) and Sherwood (Sh) numbers. Results show that the convection flow is significant up to Da = 0.1, beyond that the effect of porosity is negligible. The effect of Prandtl number (Pr) on average Nu is found to increase significantly. © 2015 Wiley Periodicals, Inc.

Heat Transfer-Asian Research

Numerical Investigation of Double Diffusive Mixed Convection Laminar Flow in Two Sided Lid Driven Porous Cavity

This paper presents the numerical investigation of double-diffusive mixed convective flow in an impermeable enclosed cavity. The uniform temperature and concentration is imposed along the vertical walls and the horizontal walls are considered as insulation. The flow behavior is analyzed when the top wall moves left side at a constant velocity (Uo) and the other walls kept remains stationary. Transport equations are solved using finite volume technique. The pressure and velocity terms are coupled by SIMPLE algorithm. The third order deferred Quadratic Upwind Interpolation for Convection Kinematics (QUICK) scheme and second order central difference scheme are applied at the inner and boarder nodal points, respectively. The present numerical simulation is compared with the reported literature and found that are in good agreement. The heat and mass transfer results are presented in the form of iso-temperature and concentration. The Lewis number (Le) and aspect ratio are varied over a wide range to analyse non-dimensional horizontal (U) and vertical velocities (V), stream line contours, temperature and concentration gradients. The present analysis is carried out at constant Prandtl (Pr=0.7), Richardson (Ri=1.0), Darcy (Da=1.0) and Reynolds (Re=100) numbers. Results show that the fluid flow and heat transfer increase with the increase in Lewis Number and low aspect ratio. The local and average Nusselt and Sherwood numbers are also presented for the different Aspect ratio and Lewis number.