HONG IK UNIVERSITY

2008 -2009

Webinar presentationWebinar presentation

for Emerging Market Vehicle Projectfor Emerging Market Vehicle Project

Webinar presentationWebinar presentation

for Emerging Market Vehicle Projectfor Emerging Market Vehicle Project

July 21 2009July 21 2009

HONG IK UNIVERSITY

2008 -2009Agenda

• Overall background

• Improvement in CAD model & meshing

• Result of Force values (CD, CL) & Shape of wake

• Comparison & Analysis

• Conclusion

HONG IK UNIVERSITY

2008 -2009Overall Background

• Our EMV vehicle is a van-type exterior.

- CD value for this shape is approximately 0.5

• Reduce the CD value.

- Not easy to reduce the frontal area of a van-type vehicle .

- A hybrid vehicle needs an energy-efficient powertrain.

• Decrease wake.

- A lower pressure zone is generated when wake is distinctly developed.

HONG IK UNIVERSITY

2008 -2009

• Received EMV CAD model (March 20th)

• Checking the CAD model for running CFD,

< 1st CAD model > < 2nd CAD model >

Overall Background

HONG IK UNIVERSITY

2008 -2009

• Surface meshing (April 7th)

- 2D mesh by Hyper works

• Volume meshing (May 4th)

- 3D mesh by Tgrid

Overall Background

HONG IK UNIVERSITY

2008 -2009

• 1st CFD results (May 16th)

< Velocity Vector > < Static Pressure_Plane >< Static Pressure_ISO >

< Pathlines colored by Particle ID >

• CD : 0.4657 (Axis : +Y)

• CL : - 0.1855 (Axis : +Z)

• Extreme wake at the back side

Overall Background

HONG IK UNIVERSITY

2008 -2009Improvement the CAD model & meshing(1)

• The model for reducing the CD value & wake

Concept1 Concept2

Model 2Model 1

HONG IK UNIVERSITY

2008 -2009Improvement the CAD model & meshing(2)

• Meshing for update-model

< Update-model >

Model 2

Model 1

HONG IK UNIVERSITY

2008 -2009Improvement the CAD model & meshing(3)

• CFD model descriptions

Update model

Elements # 4,672,738

Inlet Velocity 120 km/hr

Model descriptions Symmetric model ,Considering ground effect

Frontal area 2.49 ㎡

HONG IK UNIVERSITY

2008 -2009Result of Force values (CD, CL) & Shape of wake(1)

• Baseline model results

- CD : 0.4657 CL : - 0.1855

< Velocity Vector > < Static Pressure_Plane >

HONG IK UNIVERSITY

2008 -2009Result of Force values (CD, CL) & Shape of wake(2)

• Baseline model

< Shape of wake >

HONG IK UNIVERSITY

2008 -2009Result of Force values (CD, CL) & Shape of wake(3)

• Update-model

- CD : 0.4536 CL : - 0.1603

< Velocity Vector > < Static Pressure_Plane >

HONG IK UNIVERSITY

2008 -2009Result of Force values (CD, CL) & Shape of wake(4)

• Update-model

< Shape of wake >

HONG IK UNIVERSITY

2008 -2009Comparison & Analysis

Baseline model Update model Improvement(%)

CD 0.4657 0.4536 2.59

CL - 0.1855 - 0.1603 13.58

Wake Significant wake reduction

• Comparison

HONG IK UNIVERSITY

2008 -2009Conclusions

By attaching a small protrusion on the rear part of the roof,

achieved the reduction of wake phenomena

So does drag coefficient!!

• As a result, we could simply improve the quality of aerodynamical

efficiency by not changing much the form of existing van.

HONG IK UNIVERSITY

2008 -2009

Thank you