Investigation of Shell and Tube Heat Exchanger with Nano Fluid using ANSYS

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1 IJSTE - International Journal of Science Technology & Engineering Volume 2 Issue 06 December 2015 ISSN (online): X Investigation of Shell and Tube Heat Exchanger with Nano Fluid using ANSYS V. Ajaykumar T. Sudhakar PG Scholar Assistant Professor Department of Thermal Engineering Department of Mechanical Engineering R. Titusjames U. Sathishkumar Assistant Professor Assistant Professor Department of Mechanical Engineering Department of Mechanical Engineering Abstract The objective of this project is to analyze net heat transfer rate in shell and tube heat exchanger using nano particle suspended in different base fluids such as Water and Ethylene glycol. The thermophysical properties of naofluid mixture like density, thermal conductivity, specific heat, viscosity and density were predicted by analytical method. Then, the shell and tube heat exchanger using aluminium metal is created using CATIA and flow and thermal analysis is created using ANASYS. Keywords: Shell And Tube HeX, Flow Rate,Al2O3 ANSYS14.5 I. INTRODUCTION Heat exchangers have a huge application in various industrial sectors such as oil refining, chemical industries, power plants and refrigeration units. Among the various types of heat exchangers, shell and tube heat exchangers are most widely used about 35-40%. The heat transfer rate of heat exchangers can be enhanced by two techniques active and passive methods. In this work, I am going to use one of the passive technique that is addition of nanoparticle to the working fluid. II. SELECTION OF MATERIAL Aluminium After iron, aluminium is now the second most widely used metal in the world. It is well known for its low density and for its ability to resist corrosion due to the phenomenon of passivation. It has tensile strength between Mpa. Unlike other metals aluminium doesn t become brittle at low temperatures. But its strength decreases at temperature above 100 o C. High thermal conductivity, Good corrosion resistance. High reflectivity, Less weight. PROPERTY VALUES Thermal conductivity 237 W/(m K) Melting point K( C, F) Density 2.70 g/cm 3 Nanofluid Nanofluids are fluids that contain (1-100nm) sized particles. In order to enhance the thermal characteristics of convectional fluids, These nanoparticles are suspended in the base fluid by various techniques. Two-step is most commonly used for preparing nanofluid. Base Fluid Base fluids are convectional fluids that we used commonly in various industries. I have used the Water and Ethylene glycol as base fluids. The properties of base fluids are listed below, PROPERTIES ETHYLENE GLYCOL WATER Thermal conductivity 995 w/m-k 995 kg/m 3 Specific heat 4178 J/kg-k 4178 J/kg-k All rights reserved by 47

2 Nanoparticle Investigation of Shell and Tube Heat Exchanger with Nano Fluid using ANSYS Density kg/m w/m-k Viscosity The nanoparticle choosed is, AL 2O 3 Al 2O 3 is selected for the following work, there are two general classes of aluminas, the low surface area alpha alumina and high porous alumina. These later exist in several forms, of which are called gamma. PROPERTIES Type Size VALUES Alumina,gamma-Al2o3, purity:99% nm Thermal conductivity 40 w/m.k Specific heat 765 J/Kg.K Density 3970 Kg/m3 III. ANALYTICAL CALCULATION FOR PROPERTIES OF NANOFLUID MIXTTURE For calculating the properties of nanofluid the following formulas has been used. 1) Density can be calculated using mass balance equation ρnf = (1 φ) ρbf+φρp 2) Thermal conductivity K nf = ((kp+ 2k0 + 2(kp k0)ϕ)/(kp+ 2k0 (kp k0)ϕ)k0 3) Viscosity η r = η bf(1+ 2.5)φ 4) Specific heat is calculated using energy balance C p=((1 φ)ρbfcp, bf + φρp.p Properties of Ethylene Glycol Based Nanofluid Concentration Properties of Water Based Nanofluid Density Kg/m3 Specific heat J/Kg.K Thermal conductivity w/m.k Viscosity Kg/m-s Concentration Density Kg/m3 Specific heat J/Kg.K Thermal conductivity w/m.k Viscosity Kg/m-s IV. DESIGN AND AND ANALYSIS Design Datas NUMBER OF TUBES 9 OUTSIDE DIA 0.015M INSIDE DIA M LENGTH OF TUBE 0.5M SHELL DIA, DS 0.10M BUNDLE CLEARANCE M NO OF BAFFLES 6 BAFFLE CUT 30% All rights reserved by 48

3 BAFFLE THICKNESS HOT TUBE HEIGHT HOT TUBE DIA 2mm 50mm 40mm Calculation BUNDLE DIA, PITCH OF TUBES, BAFFLE SPACING, PROVISIONAL AREA, Db= do*3.93 =0.058M=58MM P= 1.25*do = m=18.75mm Bs= 0.8*Ds =0.08M=80MM A= Nt*do*3.14*L =6*0.015*3.14*0.5==0.132 m 2 Design CATIA (Computer Aided Three-dimensional Interactive Application) started as an in house devolpment in 1977 by French aircraft manufacturer Avions Marcel Dassault, at that time it was used to develop Dassult s Mirage fighter jet. CATIA offers a solution to facillate the design and manufacturing of routed systems including tubing, piping, heating, ventilating & air conditioning. In this work, CATIA V5 software is used to design the shell and tube heat exchanger. Analysis Fig. 1: shell and tube heat exchanger The model generated using CATIA is the imported in ANSYS FLUENT. ANSYS is general-purpose finite element analysis (FEA) software package The basis of thermal analysis in ANSYS is heat balance equation obtained from the principle of conservation of energy. The ANSYS program handles all three modes of heat transfer: conduction, convection, radiation and flow analysis. A fine mesh is generated using the solver to obtain exact result. The mesh file is shown in the figure. All rights reserved by 49

4 Fig. 5: Mesh file V. FLOW ANALYSIS OF SHELL AND TUBE HEAT EXCHANGER The flow analysis is carried by fixing static pressure condition and hot fluid inlet temperature 333k, cold fluid inlet 300k. Fig.6: Flow model In this task the flow model is provided with pressure based and gravity is neglected in this analysis. This figure clearly shows flow and temperature distribution. Now Enable the required residuals and Set the Surface Monitors for Mass-flow rate and Exit-velocity to proceed to calculation. Contour Plots For Water Based Al2o3 Nano Fluid % Velocity Water based Al2o3 Ethylene glycol based Al2o All rights reserved by 50

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6 VI. RESULT AND DISCUSSION From the results obtained from the anlaysis using ANSYS fluent, the net heat transfer rate is tabulated for water based al2o3 nanofluid mixture, S.NO Concentration (%) Velocity (m/s) Net heat transfer rate (w) Water based Al2O3 Ethylene glycol based Al2O Based on the results from the above table with increase in concentration and increase in velocity, the net heat heat transfer rate increases. VII. CONCLUSION The simulation is conducted in ANSYS FLUENT14.5 for AL 2O 3 with various concentration at various flow velocity. By comparing water based and ethylene glycol based nano fluid mixture, water based nano fluid mixture has maximum net heat transfer rate of 37.41w is obtained at 0.08m/s fluid velocity. All rights reserved by 52

7 REFERENCES [1] Arun Kumar Tiwari thermal performance of shell and tube heat exchanger using nanofluid, issn: ,(online): ,volume-1,issue-1,2015. [2] D.Mala, S. Sendhilnathan, A.Vembathu Rajesh, Heat transfer analysis of al2o3 nanofluid in circular tube with two different twist inserts, Jchps special issue 5: [3] M. Raja, R.M. Arunachalam and S. Suresh, Experimental studies on heat transfer of alumina /water nanofluid in a shell and tube heat exchanger with wire coil insert, International Journal of Mechanical and Materials Engineering (IJMME), Vol. 7 (2012), No. 1, [4] Elena V Timofeeva*, Wenhua Yu, Nanofluids for heat transfer: an engineering approach, a springer open journal. [5] S. Bhanuteja1, D.Azad, thermal performance and flow analysis of nanofluids in a shell and tube heat exchanger, ISSN (Online) Volume 4, Issue 5, September - October (2013), pp [6] Ramesh *, Dr. R.Vivekananthan, Application of Al2O3 Nanofluid for Enhance Heat Transfer Rate in Shell and Tube Heat Exchanger, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-issn: ,p-ISSN: X, Volume 11, Issue 2 Ver. I (Mar- Apr. 2014), PP [7] Design and rating of shell and tube heat exchangers by John E.Edwards, MNL 032A Issued 29 August 08, Prepared by J.E.Edwards of P & I Design Ltd, Teesside. [8] R.Dharun Arvind, Heat Transfer Analysis Of Shell And Tube Heat Exchanger Using Aluminium Nitride - Water Nanofluid, International Journal on Applications in Mechanical and Production Engineering Volume 1: Issue 1: January 2015, pp [9] B.Jayachandriah, K. Rajasekhar, Thermal Analysis of Tubular Heat Exchangers Using ANSYS, Volume No.3 Issue No: Special 1, pp: [10] Sandeep M, U Sathishkumar, CFD Investigation of Influence of Tube Bundle Cross-Section over Pressure Drop and Heat Transfer Rate, International Journal of Science, Engineering and Technology Research (IJSETR), Volume 4, Issue 5, May 2015 All rights reserved by 53