Body shape optimization using CFD: A case of locally built Isuzu passenger bus
Abstract
Nowadays with increase in competition in automobile sector, External aerodynamics is becoming an important field of study in recent years. This is because of its effectiveness in the study of visibility, stability and performance. The bus transportation is cheaper and easier to use than other means of transportation. However, buses have some disadvantages such as air pollution due to engine exhaust. This study was an attempt to reduce the gas emissions from buses by reducing the aerodynamic drag for fuel economy. Investigating Cd reduction, driving characteristic such as stability, applied to achieve this goal including slight modification of the outer shape of the Isuzu passenger bus. Rotating moment due to location of difference between C.G and C.P, due to center fugal force when the vehicle corner at high speed, thus situation can create rolling, yawing and pitching moment on the vehicle during operation on the road this will cause problems on the performance of car model like driving instability, also structural strength. This project starts with observing locally built bus garage Adama Ethiopia. Data collection was by measuring the real locally built Isuzu passenger bus body. A simulation of a bus model dimensions 7.7m × 2.8m × 2.3m was conducted thus, the CAD models of Isuzu passenger bus bodies of their aerodynamics CATIA software to model, CFD PHOENICS VR 2015 for simulation and analyzed, ansys workbench15 for structural strength analyses used. Input Velocity given to the CFD phoenics analysis was 60kmph, 80kmph, 100 kmph, and 115 kmph respectively. The respect to model 1 which existed bus its speed 60km/h, 80kmph, 100 kmph, and 115 kmph, the % drag coefficient reduction of the model 2 was 31.8, 29.1, 18.6, 11.9 and model 3 was 13.7, 40.6, and 39.3,15 respectively. The model 3 Isuzu passenger Bus driving stability was guaranteed when driving from 60km/h up to 100km/h with 12 m/s side wind for all speeds. But when the model Bus driving at the speed of 115km/h the value of (Mrr) was less than (Mrolling), therefore the model Bus‟s driving stability was not guaranteed when driving at the speed of 115km/h which is due to the side wind and at the high speed. The structural strength analysis was investigated Total deformation was 0.83903mm, equivalent elastic strain 0.1282mm/m, equivalent vonmisses stress was 2.5213x×107pa,normal elastic strain was 3.509×105mm/m, maximum shear elastic strain was 0.1717mm/m, maximum shear stress was 1.3208×107pa .
Nowadays With Increase In Competition In Automobile Sector, External Aerodynamics Is Becoming An Important Field Of Study In Recent Years. This Is Because Of Its Effectiveness In The Study Of Visibility, Stability And Performance. The Bus Transportation Is Cheaper And Easier To Use Than Other Means Of Transportation. However, Buses Have Some Disadvantages Such As Air Pollution Due To Engine Exhaust. This Study Was An Attempt To Reduce The Gas Emissions From Buses By Reducing The Aerodynamic Drag For Fuel Economy. Investigating Cd Reduction, Driving Characteristic Such As Stability, Applied To Achieve This Goal Including Slight Modification Of The Outer Shape Of The Isuzu Passenger Bus. Rotating Moment Due To Location Of Difference Between C.G And C.P, Due To Center Fugal Force When The Vehicle Corner At High Speed, Thus Situation Can Create Rolling, Yawing And Pitching Moment On The Vehicle During Operation On The Road This Will Cause Problems On The Performance Of Car Model Like Driving Instability, Also Structural Strength. This Project Starts With Observing Locally Built Bus Garage Adama Ethiopia. Data Collection Was By Measuring The Real Locally Built Isuzu Passenger Bus Body. A Simulation Of A Bus Model Dimensions 7.7m ?? 2.8m ?? 2.3m Was Conducted Thus, The Cad Models Of Isuzu Passenger Bus Bodies Of Their Aerodynamics Catia Software To Model, Cfd Phoenics Vr 2015 For Simulation And Analyzed, Ansys Workbench15 For Structural Strength Analyses Used. Input Velocity Given To The Cfd Phoenics Analysis Was 60kmph, 80kmph, 100 Kmph, And 115 Kmph Respectively. The Respect To Model 1 Which Existed Bus Its Speed 60km/H, 80kmph, 100 Kmph, And 115 Kmph, The % Drag Coefficient Reduction Of The Model 2 Was 31.8, 29.1, 18.6, 11.9 And Model 3 Was 13.7, 40.6, And 39.3,15 Respectively. The Model 3 Isuzu Passenger Bus Driving Stability Was Guaranteed When Driving From 60km/H Up To 100km/H With 12 M/S Side Wind For All Speeds. But When The Model Bus Driving At The Speed Of 115km/H The Value Of (Mrr) Was Less Than (Mrolling), Therefore The Model Bus?�?S Driving Stability Was Not Guaranteed When Driving At The Speed Of 115km/H Which Is Due To The Side Wind And At The High Speed. The Structural Strength Analysis Was Investigated Total Deformation Was 0.83903mm, Equivalent Elastic Strain 0.1282mm/M, Equivalent Vonmisses Stress Was 2.5213x??107pa,Normal Elastic Strain Was 3.509??105mm/M, Maximum Shear Elastic Strain Was 0.1717mm/M, Maximum Shear Stress Was 1.3208??107pa .
Nowadays With Increase In Competition In Automobile Sector, External Aerodynamics Is Becoming An Important Field Of Study In Recent Years. This Is Because Of Its Effectiveness In The Study Of Visibility, Stability And Performance. The Bus Transportation Is Cheaper And Easier To Use Than Other Means Of Transportation. However, Buses Have Some Disadvantages Such As Air Pollution Due To Engine Exhaust. This Study Was An Attempt To Reduce The Gas Emissions From Buses By Reducing The Aerodynamic Drag For Fuel Economy. Investigating Cd Reduction, Driving Characteristic Such As Stability, Applied To Achieve This Goal Including Slight Modification Of The Outer Shape Of The Isuzu Passenger Bus. Rotating Moment Due To Location Of Difference Between C.G And C.P, Due To Center Fugal Force When The Vehicle Corner At High Speed, Thus Situation Can Create Rolling, Yawing And Pitching Moment On The Vehicle During Operation On The Road This Will Cause Problems On The Performance Of Car Model Like Driving Instability, Also Structural Strength. This Project Starts With Observing Locally Built Bus Garage Adama Ethiopia. Data Collection Was By Measuring The Real Locally Built Isuzu Passenger Bus Body. A Simulation Of A Bus Model Dimensions 7.7m ?? 2.8m ?? 2.3m Was Conducted Thus, The Cad Models Of Isuzu Passenger Bus Bodies Of Their Aerodynamics Catia Software To Model, Cfd Phoenics Vr 2015 For Simulation And Analyzed, Ansys Workbench15 For Structural Strength Analyses Used. Input Velocity Given To The Cfd Phoenics Analysis Was 60kmph, 80kmph, 100 Kmph, And 115 Kmph Respectively. The Respect To Model 1 Which Existed Bus Its Speed 60km/H, 80kmph, 100 Kmph, And 115 Kmph, The % Drag Coefficient Reduction Of The Model 2 Was 31.8, 29.1, 18.6, 11.9 And Model 3 Was 13.7, 40.6, And 39.3,15 Respectively. The Model 3 Isuzu Passenger Bus Driving Stability Was Guaranteed When Driving From 60km/H Up To 100km/H With 12 M/S Side Wind For All Speeds. But When The Model Bus Driving At The Speed Of 115km/H The Value Of (Mrr) Was Less Than (Mrolling), Therefore The Model Bus?�?S Driving Stability Was Not Guaranteed When Driving At The Speed Of 115km/H Which Is Due To The Side Wind And At The High Speed. The Structural Strength Analysis Was Investigated Total Deformation Was 0.83903mm, Equivalent Elastic Strain 0.1282mm/M, Equivalent Vonmisses Stress Was 2.5213x??107pa,Normal Elastic Strain Was 3.509??105mm/M, Maximum Shear Elastic Strain Was 0.1717mm/M, Maximum Shear Stress Was 1.3208??107pa .