Study and design of a three way catalytic converter
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1) The document describes the design and analysis of catalytic converters through computational fluid dynamics (CFD) simulations. 2) Six CAD models of catalytic converters were generated by varying inlet cone length and substrate dimensions. The models were simulated using both ceramic and steel wire mesh substrates. 3) The CFD results were analyzed to compare pressure variation, recirculation zones, and velocity vectors between the different designs. Models with longer inlet cones and steel wire mesh substrates performed better with lower back pressure and fewer recirculation zones.
![LITERATURE SURVEY
• A review paper on Catalytic Converter for Automotive Exhaust Emission by Prof.
Bharat S Patel and Mr.Kuldeep D Patel
• Design, analysis of flow characteristics of catalytic converter and effects of back
pressure on engine performance by Dr. R. Senthil in IJREAT , March 2013
• Design optimization of Catalytic Converter to reduce Particular Matter and Achieve
limited Back Pressure in Diesel Engine by CFD by B.Balakrishna and Srinivasarao
Mamidala
• Modeling and Simulation of different gas Flow Velocity and pressure in catalytic
converter with porous by K.Mohan Laxmi and V.Ranjith Kumar
• Automotive catalytic converters: current status
and some perspectives by J. Kaspar, N. Hickey and Paolo [ELSEVIER]](https://image.slidesharecdn.com/btechfinalpresentation8thsem-150725162352-lva1-app6892/85/Study-and-design-of-a-three-way-catalytic-converter-6-320.jpg)
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Study and design of a three way catalytic converter
- 1. DESIGN AND ANALYSIS OF CATALYTIC CONVERTER By Aakash Srivastava 11-1-2-011 Shivam Chaubey 11-1-2-019 Ankan Jyoti Phukan 11-1-2-046 Vivek Raj Pal 11-1-2-051 Ravi Ranjan 11-1-2-075 Under supervision of Mrs. Sumita Deb Barma Department of Mechanical Engineering National Institute of Technology, Silchar
- 2. 2 INTRODUCTION • Most effective after treatment for reducing engine emissions. • Lowers temperature needed for oxidation of CO and HC by using catalysts. • Three way converter reduces NOx in addition to oxidation of CO and HC. • Substrates used to hold catalyst may be made of Ceramic honeycomb, metallic monolith or steel wire mesh • Various minute channels in substrate form honeycombs in which reactions occur. • Alumina is used as wash coat and holds catalysts including Rhodium, Palladium and Platinum
- 3. COMPARISON BETWEEN SUBSTRATES Factors Ceramic Metal Steel Wire Thermal conductivity(W/m- K) 32 24 16.7 Porosity 0.69 0.91 0.864 Open-frontal area(%) 69 91 86.4 Manufacturing ease Difficult Difficult Easy Wall thickness 0.15 mm 0.05 mm 0.114 mm • Due to manufacturing ease and low thermal mass , steel wire mesh is found better than the other two
- 4. PROBLEM STATEMENT • Compare various catalytic chamber design parameters such as inlet cone length, type of substrate medium, diameter and length of substrate • CFD simulations are done on the generated cad models to study the loss of pressure and re-circulation zones generated •Methods used Varying inlet cone angle Varying inlet cone length Varying substrate dimensions Varying substrate type (Ceramic/Steel Wire Mesh)
- 5. OBJECTIVES 1. Preparing CAD model for various test cases to be studied 2. Meshing in ICEM CFD followed by CFD simulations in ANSYS FLUENT 3. Post-processing of CFD results to compare different chamber designs on basis of minimum back pressure and recirculation zones developed 4. Conclusion giving factors that lead to favourable chamber design.
- 6. LITERATURE SURVEY • A review paper on Catalytic Converter for Automotive Exhaust Emission by Prof. Bharat S Patel and Mr.Kuldeep D Patel • Design, analysis of flow characteristics of catalytic converter and effects of back pressure on engine performance by Dr. R. Senthil in IJREAT , March 2013 • Design optimization of Catalytic Converter to reduce Particular Matter and Achieve limited Back Pressure in Diesel Engine by CFD by B.Balakrishna and Srinivasarao Mamidala • Modeling and Simulation of different gas Flow Velocity and pressure in catalytic converter with porous by K.Mohan Laxmi and V.Ranjith Kumar • Automotive catalytic converters: current status and some perspectives by J. Kaspar, N. Hickey and Paolo [ELSEVIER]
- 7. DESIGN CALCULATION Engine Specification Shape of Catalytic Converter- Cylindrical Space velocity- 30000 hr-1 Volume flow rate- 30.615 m3/hr Catalyst Volume- 1.0205e-3 m3 Type 4 S, SI Speed 1000 rpm Bore 100 mm Stroke 130 mm Volume flow rate=Space Velocity*Catalyst Volume Model Diameter of Substrate Length of Substrate 1 100 mm 153.5 mm Model Diameter of Substrate Length of Substrate 2 80.6 mm 200 mm
- 8. DESIGN CALCULATION Model 1.1 1.2 1.3 2.1 2.2 2.3 Inlet diameter 40 mm 40mm 40mm 40mm 40mm 40mm Outlet diameter 40mm 40mm 40mm 40mm 40mm 40mm Substrate diameter 100 mm 100mm 100mm 80.6mm 80.6mm 80.6mm Substrate length 153.5mm 153.5mm 153.5mm 200mm 200mm 200mm Inlet cone Length 30mm 40mm 60mm 30mm 40mm 60mm Outlet cone Length 40mm 40mml 40mm 40mm 40mm 40mm • Six different cad models were generated using the above readings
- 9. CAD MODEL • CAD models were generated using CATIA V5 Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 10. 10 Unstructured Grid is chosen over Structured Grids Reasons: • Less Mesh Generation Time • Good result accuracy obtained with improved mesh quality MESHING is done in following phases: 1. Creating surface mesh using Triangular mesh 2. Creating Tetrahedral Volume Meshes Softwares used for mesh generation includes ICEM-CFD. Triangular Mesh Tetrahedral Mesh MESH
- 11. MESH Quantity Stat Tetrahedral Volume mesh Surface Mesh (Magnified View ) Triangular Surface mesh Quality Stat
- 12. SOLVER •Pressure based solver was used. • A porous medium was used to simulate the effect of substrate. • Porosity, Inertial resistance and Viscous resistance value was obtained for Ceramic and Steel wire substrate • For Ceramic substrate Porosity 0.69 Inertial Resistance(1/m) - 20.414 Viscous Resistance(1/m2) - 3.864e+7
- 13. SOLVER • For steel wire substrate Equation for pressure loss at varying velocity for 1 m length of substrate was obtained from Technical Paper • Comparing with equivalent equation for any homogeneous media • The following values were obtained Inertial Resistance(1/m)- 2.2857 Viscous Resistance(1/m2)- 1.21e+5 Ploss= 1.40v2+2.189v Ploss=-C2*0.5*p*v2-u/a*v
- 14. SOLVER SETTINGS Scale factor = 0.001 Pressure Based solver Viscous model: Standard k-epsilon, Standard wall function Convergence tolerance = 0.000001 Cell Zone Condition: Substrate- Porous and laminar Zone Pressure under relaxation=0.2 Velocity at Inlet= 6.77 m/s Outlet gauge pressure= 0 Pa Respective Inertial and Viscous Resistance values Momentum under relaxation=0.5 Other settings are kept standard and default Solved in Fluent v6 • 12 CFD simulations were performed : Two for each model depending on Ceramic and Steel wire substrates used.
- 15. POST PROCESSING RESULTS • The post processing of simulation results was done which were then grouped and interpreted according to following factors Pressure Variation through the Catalytic converter Recirculation zones produced Velocity variation during fluid flow
- 16. POST PROCESSING RESULTS Pressure variation when using Ceramic Substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 17. POST PROCESSING RESULTS Pressure variation when using Wire Mesh Substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 18. POST PROCESSING RESULTS Recirculation zones when using Ceramic Substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 19. POST PROCESSING RESULTS Recirculation zones when using Wire Mesh Substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 20. POST PROCESSING RESULTS Velocity vectors when using ceramic substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 21. POST PROCESSING RESULTS Velocity vectors when using Wire Mesh substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 22. POST PROCESSING RESULTS Velocity vectors when using Ceramic substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 23. POST PROCESSING RESULTS Velocity vectors when using Wire Mesh substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 24. POST PROCESSING RESULTS Pressure variation when using ceramic substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 25. POST PROCESSING RESULTS Pressure variation when using Wire substrate Model 1.1 Model 1.2 Model 1.3 Model 2.1 Model 2.2 Model 2.3
- 26. POST PROCESSING RESULTS Back Pressure for Model 1 (Ceramic vs. Wire Mesh Substrate) Ceramic Back Pressure (Pa) Model 1.1 181.7 Model 1.2 177.9 Model 1.3 165.93 Wire Mesh Back Pressure (Pa) Model 1.1 42.4 Model 1.2 41.8 Model 1.3 40.6 150 155 160 165 170 175 180 185 190 195 200 MODEL 1.1 MODEL 1.2 MODEL 1.3 BACK PRESSURE CERAMIC 35 37.5 40 42.5 45 47.5 50 MODEL 1.1 MODEL 1.2 MODEL 1.3 BACK PRESSURE WIREMESH
- 27. POST PROCESSING RESULTS Back Pressure for Model 2 (Ceramic vs. Wire Mesh Substrate) 270 272.5 275 277.5 280 282.5 285 287.5 290 292.5 295 297.5 300 MODEL 2.1 MODEL 2.2 MODEL 2.3 BACK PRESSURE CERAMIC 40 42 44 MODEL 2.1 MODEL 2.2 MODEL 2.3 BACK PRESSURE WIREMESH Ceramic Back Pressure (Pa) Model 2.1 288.34 Model 2.2 283.45 Model 2.3 281.8 Wire Mesh Back Pressure (Pa) Model 2.1 42.7 Model 2.2 42.29 Model 2.3 41
- 28. CONCLUSION • We can see from the results that the maximum pressure drop of 288.34 Pa was seen for Model 2.1 when simulated for Ceramic substrate while the minimum back pressure was created for Model 1.3 when simulated for Wire Mesh Substrate. • It was observed that the back pressure decreased with increase in inlet cone length in each of the cases irrespective of type of substrate. • Due to recirculation zones formed, there was a marked decrease in amount of gas passing through the substrate thus reducing the effectiveness of the converter. • Model 2.3 shows lowest back pressure but due to formation of recirculation zones , the converter’s effectiveness should be lowered ,thus, Model 2.2 with wire mesh substrate is considered the best candidate for further study and development of converter.