CFD

To Study, design and manufacture a technological demonstrator within 6 months was the goal of the companies involved in the PPNMC (Pole de la Performance de Nevers Magny-Cours). with the first electrical racecar with a range extender was presented.

Through the different stages of the project, will be presented ACE's skills and capabilities that were used to reduce leadtimes and cost, while improving the quality and process.

NOAO : 100% Numerical Conception

Step 1 : Reverse engineering of targets

Thanks to Romer's reverse engineering system, we have scanned different type of cars (race and roadcar). Those reference cases being considered as target criterias :
-Complete car scanning including bodywork, underbody and mechanical parts.
-Surfacic reverse eengineering with Polyworks 12.
-Mechanical and surfacic car construction with Catia V5.

Step 2 : CFD of targets

With new high speed process, been developed in-house for the past 3 years with Open Foam, we have been able to compute the target cars with the following conditions :
-Automatic Meshing, CFD set up and Ensight Post-processing.
-DDES Unsteady CFD
-Thermal exchange through radiators.

Step 3 : Parts from shleves to CAD

Standard component from road cars have been
used in this project. As their CAD file were not
available, we had to scan them to include them:
-3 cylinders Ignition Combustion Engine
-Exhaust pipes
-Radiator Fan, Rims, tyres...

Step 4 : Design and CAD of the Project

Design and mechanical design of the powertrain were the baseline of the car aerodynamic and thermal study. Therefore with those key points we have been able to speed up the process leadtime tahnks to the folowing point :
-Transfer from 2D sketches to 3D CAD Design.
-Car surfaces and geometry (wheelbase, track...) considered as parameters with Caita V5 enabling to accelerate the iteration between CAD and CFD.
-Validation with the digital model of design criterias such as dashboard, driver visibility...

Step 5 : Aerodynamics and Thermal Sutdies

Over 100 CFD computations were done on a 64 Cores and 192 Gb RAM cluster, allowing to anticipate faster and to widen the CFD areas :
-Complete cooling architecture and system design (convection / water line from the water pump to the radiator and the air ducting).
-Powertrain and generator thermal environment constraints (conduction and radiation).
-Aerodynamics coefficient improvements for range (drag) and performance (downforce).

Step 6 : CAD, Production and Wind tunnel Testing

With our Romer partnership, we have developed a new methodology of wind tunnel model manufacturing in order to bring the cost down. We have also started new technology such as soft tires, wheels attached , pressure and mass flow sensors in order to correlate CFD and Wind tunnel and Track testing : We reached our goal !