International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016) Computational Fluid Dynamics: Research Tool for Analysis of Various Parts of Automotive Systems V.S.Kathavate1* A.S.Adkine 2 1* Department of Metallurgy and Materials Science, College of Engineering, Pune, 411005 (India) Department of Mechanical Engineering, Shreeyash College of Engineering and Technology, Aurangabad, 431005 (India) 2 ABSTRACT- This current article accounts for the analysis of engine mounting bracket by using Computational fluid dynamics technique. ANSYS software was used for the analysis purpose and results are so obtained pertaining to the optimized level. This paper gives the little idea about the new modern techniques used in the CFD and view progress that has been made the over the distance revolution in the field of engineering with the reinforcement of new modern technologies recently developed. It so addresses the scientist, engineers and mathematician who are willing to deal with the field of computational fluid dynamics. The results were analyzed for stresses and deformations. The design was tested for different materials like Aluminium, ERW-1 and ERW-2 along with suitability of material. flow, as governed by the NEVIER-STOKES equation was performed at Los Alamos National Labs[10]. Meanwhile in two dimensional (2-D) real, a number of panel codes have been developed for an airfoil analysis and design. The codes were typically dealt with boundary layer analysis and so that which would results in elimination of viscous effect[10,12].Currently, its main application is as an engineering method, to provide data that is complementary to theoretical and experimental data. This is mainly the domain of commercially available codes and in-house codes at large companies[11,12]. Some fundamentals of CFD are (figure 1); Key words: CFD–Computational fluid dynamics, Discretization, FEM – Finite element method, Grid, ERW-1, ERW-2, ANSYS. I. INTRODUCTION Computational fluid dynamics generally known as CFD is the progressive research tool for analysis and evaluation for various types of mechanical parts designed by the mechanical industries or automobile sector. The main purpose of the CFD, using as the research tool is that to impart a forum for the cross fertilization of the ideas, tools, techniques and with the imposement of aeronautical science, geophysics and environmental science[1-2]. This is applicable for all the disciplines where fluid flow is taken into an account. Being the best designer one should able to design the product with maximum efficiency, more comfort ability that would meet the various requirements of customers with the phenomenon of optimum cost[3]. It is very important that to realize the functional requirement and appearance of the existing product. In many cases the functional requirements results in various types of shapes and sizes which has aesthetically pleasant appearance[4]. For ex.: The evaluation of the streamline shaped Boeing is results in the studies of Aerodynamics for the precision and effortless speed. The first work using computer model ISSN: 2231-5381 Fig.1 Basic concepts of CFD A. STAGES OF CFD: 1) During Initial Stage of Processing: a] The geometry (physical bounds) of the problem defined. b] The volume occupied by the fluid is divided into the small discrete cells (mesh). c] Physical modeling in terms of all the parameters (i.e. kinematic, thermodynamic, heat transfer etc.) (Motion equation+ enthalpy + radiation + species conversion). 2) Processing Stage: a] Boundary conditions are defined involving specified fluid behaviour and properties of boundaries of the problem are defined. b] The simulation is started and the equations are http://www.ijettjournal.org Page 344 International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016) solved iteratively as steady state or the transient state. 3) Post Processing: Finally, the analysis is done and visualization for resulting solution. 4) Pre-screening and Preparation: After identifying the list of problems and recognizing them, they must be screened and put them into the decreasing order of profit and increasing order of investment as well as difficulty of breaking technology. This process is carried out to collect technical data, maintenance data and Performance specifications. Technical data helps to generate in the stages including dimensions of parts to be analyzed, surface finish interfaces, tolerances and performance and testing quality assurance requirements. However engineering drawings of the models are prepared for the prototypes and drafted with the help of different software exiting in CAD (i.e. COMPUTER AIDED DESIGN). 5) Numerical Simulation: a] System-level CFD problems (Includes all components in the product) b] Component or detail-level problems (Identifies the issues in a specific component or a subcomponent) c] Different tools for the level of analysis Coupled physics (fluid-structure interactions). B. GENERAL FACTS ABOUT DISCRETIZATION: Discretization in space produces a system of ordinary differential equation for unsteady state problems and algebraic equation for steady state problems. Implicit or semi implicit methods are generally used for integrating the ordinary differential equations which leads to produce a system usually non linear equation[14]. So by applying NEWTON and PICARD’S iteration, which will then produces a system of linear algebraic equation which is non symmetric in the presence of advection and indefinite in the presence of the incompressibility[1]. C. METHOD OF DISCRETIZATION: Domain is discretized into a finite set of control volumes or cells. The discretized domain is called the “grid” or the “mesh.” ISSN: 2231-5381 t • General conservation (transport) equations for mass, momentum, energy, etc., are discretized into algebraic equations. • All equations are solved to render flow field. dV V V dA A dA A S dV V Table 1 Terms used in equation Eqn. continuity x-mom. y-mom. energy 1 u v h D. GRID GENERATION SOFTWARE: There are in numerous methods available for generation of mesh. But most convenient method is by using Finite Element Method (FEM). In mathematics Finite Element Method (FEM) is numeric technique for finding approximate solution to boundary condition problem. It uses variation method (the calculus of variation) to minimize the error function and to produce stable solution. Variety of specializations under the umbrella of the mechanical engineering discipline (such as aeronautical, biomechanical, and automotive industries) commonly use integrated FEM in design and development of their products[13]. Several modern FEM packages include specific components such as thermal, electromagnetic, fluid, and structural working environments. In a structural simulation, FEM helps tremendously in producing stiffness and strength visualizations and also in minimizing weight, materials, and costs. FEM allows detailed visualization of where structures bend or twist, and indicates the distribution of stresses and displacements. FEM software provides a wide range of simulation options for controlling the complexity of both modeling and analysis of a system. FEM allows entire designs to be constructed, refined, and optimized before the design is manufactured. http://www.ijettjournal.org Page 345 International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016) Fig.2 Procedure of CFD analysis II. ENGINE MOUNTING BRACKET In an automotive vehicle, the engine rests on brackets which are connected to the main-frame or the skeleton of the car. Hence, during its operation, the undesired vibrations generated by the engine and road roughness can get directly transmitted to the frame through the brackets[15]. This may cause discomfort to the passenger(s) or might even damage the chassis. When the operating frequency or disturbance approaches the natural frequency of a body, the amplitude of Vibrations gets magnified. The need for light weight structural materials in automotive applications is increasing as the pressure for improvement in emissions and fuel economy increases. The most effective way of increasing automobile mileage while decreasing emissions is to reduce vehicle weight[1,16]. The noise and vibration occur because the power that is delivered through bumpy roads, the engine, and suspension result in the resonance effect in a broad frequency band. The ride and noise characteristics of a vehicle are significantly affected by vibration transferred to the body through the chassis mounting points from the engine and suspension[1]. There are two major problems that engineers must deal with when it comes to vibration isolation. The first problem is force isolation, which is frequently encountered in rotating or reciprocating machinery with unbalanced masses. The main objective in this problem is to minimize the force transmitted from the machine to the supporting foundation. The second problem is motion isolation. The natural frequency of the mounting system should be lower than the engine disturbance frequency to avoid the excitation of the mounting system resonance. This will ensure a low transmissibility ISSN: 2231-5381 Fig 3: Isometric view of the mounting bracket III. EXPERIMENT A. Static Structural Analysis of Engine Mounting: Static Analysis deals with the conditions of the equilibrium of the bodies acted upon by forces. A Static analysis is used to determine the displacements, stresses, strains and forces in structures and components caused by loads that do not induce significant inertia and damping effects. The kind of loading that can be applied in static analysis includes External applied forces, pressures and moments Steady state inertial forces such as gravity and spinning imposed non-zero displacements. Fig 4: Flow chart for Static Structural analysis B. Alternative Material for Engine Mounting Bracket: a] ALUMINUM: Aluminum has only about one third the density of steel and the most commercial aluminum alloys posses substantially higher specific strength than steel. A vehicle weight reduction would not only result in higher oil savings, but also gives a significant reduction in emission. For these reasons there is preference to use more aluminium and replace steel in automotive applications. Aluminium alloy under consideration has following material properties: Young’s modulus – 6.9× 109 N/m2 Poisson’s ratio – 0.33 Density – 2770 Kg/m3 Yield strength in tension & compression – 95×106 N/m2. http://www.ijettjournal.org Page 346 International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016) b] ERW-1: Electric resistance welded or high frequency induction welded steel tubes designated as ERW. It comprises of 0.12%C, 0.60%Mn, 0.04%S and 0.04%P. This ERW-1 steel contains following mechanical properties (Table-2); Table-2 Mechanical Properties of ERW-1 Designation ERW-1 Tensile Strength (MPa) 310 Yield Strength (MPa) 160 % Elongation on (Gauge length ) 20 c] ERW-2: This ERW-2 steel contains 0.25%C, 1.20%Mn, 0.04%S and 0.04%P. It possesses following mechanical properties (Table-3); Table 5 Maximum displacement ERW1 v/s Aluminum v/s ERW2 Maximum displacement First Mode ERW-1 (mm) 29.19 Aluminum (mm) 29.18 ERW-2 (mm) 25.60 Second Mode 31.13 31.117 27.89 Third Mode 33.22 33.26 30.10 Fourth Mode 34.84 34.82 31.15 Fifth Mode 47.38 47.38 38.83 Sixth Mode 35.51 35.49 31.90 Tensile Strength (MPa) Yield Strength (MPa) ERW-2 380 240 % Elongation on (Gauge length ) 15 IV. RESULTS AND DISSCUSSION A. Modal Analysis: Modal analysis was done for obtaining the different frequencies for Aluminum, ERW-1, and ERW-2 materials (Table 4); Table 4: Frequency ERW-1 v/s Aluminum v/s ERW-2 Frequency 1 2 3 4 5 6 ERW-1 (Hz) 68.897 87.596 106.05 195.83 266.74 520.41 Aluminum (Hz) 68.796 87.407 106.05 195.79 266.69 520.28 ERW-2 (Hz) 52.56 68.409 85.234 160.652 221 448.324 As the mode of frequency was changed, initially no change was observed in ERW-1 and Aluminum material. But ERW-2 shows large variation in frequency as compared to ERW-1 and Aluminum. This is probably due to the varying composition and superior mechanical properties of ERW-2 material(figure 5). Frequency (Hz) 600 ERW-2 Aluminum ERW-1 MODES Fig.6 Maximum displacement ERW-1 v/s ERW-2 The convergence of frequencies for ERW-2 material is good. The first excitation frequency value for ERW-2 is higher than that of excitation frequency range of engine. The values of frequencies are nearly same for ERW-1 and aluminum bracket. B. Alternative Material for Engine Mounting Bracket: ANSYS software was used for stress analysis and results are tabulated in Table-5; Table 6: Stress Distribution among ERW-2, Aluminum and ERW-1 500 400 ERW- 2 Aluminum alloy ERW-1 82.96 64.588 68.87 1.086 3.88 1.90 ERW-1 300 Aluminum 200 ERW-3 100 0 45 35 25 15 5 First Mode Second… Third Mode Fourth… Fifth Mode Sixth Mode Designation DISPLACEMENT IN mm Table-3 Mechanical Properties of ERW-2 Mode of Frequency Von-Mises stress(max) (MPa) Total deformation (mm) Fig.5 Frequency ERW-1 v/s Aluminum v/s ERW-2 ISSN: 2231-5381 http://www.ijettjournal.org Page 347 International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016) [3] W. Anderson, R. Rausch, D. Bonhaus, “Implicit multigrid algorithms for incompressible turbulent flows on unstructured grids”, (1996) J. Comput. Phys. Vol.128 pp 391–408. STRESS AND DEFORMATION 350 250 150 ERW-1 50 ALUMINUM -50 ERW-2 -150 Fig.7 Comparison between ERW-2, Aluminum and ERW-1 It can be anticipated that ERW-2 is the best material for the desired application. [4] M.J.H. Anthonissen, B. van’t Hof, A.A. Reusken, “A fnite volume scheme for solving elliptic boundary value problems on composite grids”, Computing Vol.61 pp 285–305. [5] S R Shaha, S V Jain, R N Patel, V J Lakhera, “CFD-for pump: a review of state-of-the-art” (2013) Procedia Engineering Vol. 51 pp 715 – 720. [6] Usha, P.Syamsundar, “Computational analysis on performance of a centrifugal pump impeller”, (2010) Proceedings of the 37th National & 4th International Conference on Fluid Mechanics and Fluid Power. Chennai, India, paper TM-07. [7] Yasushi Ito “Challenges in unstructured mesh generation for practical and efficient computational fluid dynamics simulations”, (2013) Computers & Fluids Vol.85 pp 47–52. [8] P.Wesseling, Principles of Computational fluid dynamics, Springer link (2001). V. CONCLUSIONS [9] John W. Slater, CFD analysis NASA OFFICIAL, Tuesday 17,2008, www.grc.nasa.gov.in Computational Fluid Dynamics is a powerful way of modeling fluid flow, heat transfer, and related processes for a wide range of important scientific and engineering problems. A fully integrated numerical method for flutter analysis with a coupled fluidstructure interaction is presented. The technique replaces a hands-on process guided by experience to yield accurate and reliable low fidelity models. The Computational fluid dynamics tool, ANSYS has been used to analyze the engine mounting bracket. The results obtained from the static structural and modal analysis shows that ERW-2 steel is better than ERW-1 steel. From the results it can be said that the ERW-2 steel bracket is safe for the required application. This work also contributes to the defining alternative material engine mounting bracket, in which aluminum alloy were studied along with ERW-1 and ERW- 2 steel. After analyzing the results, it can be anticipated that ERW-2 can be proffered over Aluminum and ERW-1. Stiffness of ERW-2 found better than Aluminum, so it may be used for required application of engine mounting bracket. [10] ZHANG Baoqiang, CHEN Guoping a, GUO Qintao, “Static Frame Model Validation with Small Samples Solution Using Improved Kernel Density Estimation and Confidence Level Method” (2012) Chinese Journal of Aeronautics, vol. 25 pp 879-886. [11] ZHANG Man, FU Zhenbo, LIN Yuzhen, LI Jibao“CFD Study of NOxEmissions in a Model Commercial Aircraft Engine Combustor” (2012), Chinese Journal of Aeronautics vol. 25 pp 854-863. [12]Gareth A. Taylor b, Michael Hughes, Nadia Strusevich, KoulisPericleous“Finite volume methods applied to the computational modelling of welding phenomena” (2002) Applied Mathematical Modelling vol.26 pp 309–320. [13] Slawomir Kozieland, Leifur Leifsson, “Multi-level CFDbased Airfoil Shape Optimization with Automated Low-fidelity Model Selection” (2013) Procedia Computer Science vol.18 pp 889 –898. [14] ZHENG Yun, YANG Hui, “Coupled Fluid-structure Flutter Analysis of a Transonic Fan” (2011) Chinese Journal of Aeronautics vol.24 pp 258-264. [15] Jasvir Singh Dhillon, Priyanka Rao, V.P. Sawant “Design of Engine Mount Bracket for a FSAE Car Using Finite Element Analysis” (September 2014) Int. Journal of Engineering Research and Applications ISSN : 2248-9622, Vol. 4, Issue 9 (Version 6), , pp.74-81. [16] Kichang Kim and Inho Choi, “Design Optimization Analysis”, SAE TECHNICAL,2003-01-1604. REFERENCES [1] A.S.Adkine, V.S.Kathavate, G.P.Overikar, S.N.Doijode, “Static Behaviour of Engine Mounting Bracket” (April 2015) International Advanced Research Journal in Science, Engineering and Technology Vol. 2, Issue 4, pp 68-73. [2] P. Wesselinga;, C.W. Oosterleeb, “Geometric multigrid with applications to computational fuid Dynamics” (2001) Journal of Computational and Applied Mathematics Vol.128 pp 311–334. ISSN: 2231-5381 http://www.ijettjournal.org Page 348 International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016) AUTHOR’S AUTOBIOGRAPHY: V.S.Kathavate is the M.Tech. research student studying in College Of Engineering, Pune 05. He has done his UG in Mechanical Engineering with honours in First Division with Distinction from Hitech Institute of Technology, Aurangabad. His main interest lies in Heat and Mass Transfer, Micro Machining Process, Computational Fluid Dynamics, and Boundary Layer Thickness. Besides That Corrosion and its Protection is also his area of research. During his UG he has done the major research work on An Experimental Investigation of Micromilling. This article was published in Internatio nal Journal of Technology Enhancements and Emer ging Engineering Research (ISSN 2 347-4289) for April 2015 issue. He has also attended the various National level Conferences on Mechanical Engineering, Materials Science and furnished the var ious papers and articles in them. The article Static Behaviour of Engine Mounting Bracket published in International Advanced Research Journal on Science, Engineering and Technology for April, 2015 issue was also co-authored by him. ISSN: 2231-5381 A.S.Adkine is the Assistant Professor in Shreeyash College of Engineering and Technology, Aurangabad. His main enthu stands in the subjects like Theory of Machines, Mechanical Drawing and Management related subjects. During his career he is very well known and versatile personality among his subordinates and his student. Currently his ongoing research is on static and dynamic behaviour of engine mounting bracket. He has his publication on Static Behaviour of Engine Mounting Bracket. This article was published in International Advanced Research Journal on Science, Engineering and Technology for April, 2015 issue. Prof. Adkine had attended and conducted the vario us workshops and sessions on various subjects like Vibratio n analysis, ANSYS so ftware tools, Rapid prototyping, and vario us Manufacturing process. http://www.ijettjournal.org Page 349