5 CFD Applications for Automotive Simulations

The automotive sector relies on innovation to stay competitive. Here’s how CFD gives you an edge.

The automotive industry faces constant pressure from all sides to release products that better meet consumer demand and regulatory controls. Each year, automotive vehicles are expected to become more fuel efficient, release fewer emissions, have more powerful engines, and meet higher standards of luxury. The engineering behind these innovations requires long hours of design, testing, prototyping, and refinement.

However, producing and testing physical prototypes is both time-consuming and expensive, which is why auto manufacturers and their suppliers turn to CAE simulations to virtually prototype and experiment early in the development process. One of the most crucial forms of CAE is computational fluid dynamics (CFD).

CFD enables engineers to predict how fluids behave in various conditions. CFD can be used to simulate aerodynamics, transonic or turbulent flows, weather conditions, heat transfer, and related chemical phenomena. As the automotive industry moves toward electric vehicles, CFD helps manufactures simulate thermal management in the motor and battery. By creating computational models of these scenarios, engineers can improve product design and development throughout the manufacturing process.

Computer-aided engineering (CAE) simulations aid manufacturers by:

• Predicting performance of complex systems
• Enabling design experimentation early and often.
• Reducing the amount of physical prototyping.
• Reliably validating ideas and guiding decision making.
• Detailing specifications for product development.

CFD can also accurately model scenarios that are hard to test for, including complex and crowded assemblies, extreme environmental conditions, or a wide range of improbable or unusual use cases.

In the automotive industry, where every component of a vehicle involves complex interactions with liquids, gasses, thermal transfer, and chemical reactions, CFD has become an essential part of the development process. For auto manufacturers interested in learning more about how to innovate more effectively, here are five areas where they can apply CFD simulations to their development processes.

1. Vehicle aerodynamics.

The aerodynamic qualities of a sports car differ vastly from those of a semi or a minivan. The features that may appeal to one market segment—an eco-friendly design for city drivers—may run contrary to those required by another, such as a rugged, heavy-duty pickup truck.

CFD models the way aerodynamic forces affect a vehicle in several ways. Aerodynamic drag is horizontal force against forward motion of the car, affecting speed and fuel efficiency. Aerodynamic lift is vertical force which, in automotive design, can result in a vehicle losing contact with the ground, which in turn can result in an accident. Finally, aeroacoustics involve the noise generated by a design.

CFD allows manufacturers to model the effect changes will have on the aerodynamics of a vehicle, so that engineers can evaluate whether the impact of these changes meets performance requirements.

2. Wheel hydrodynamics.

As the only part of the car to contact the road, tire performance is critical for the performance and handling of a vehicle. Factors such as the materials used and the design of the tread can impact how a tires functions in hot or cold weather, how much traction they provide, and, most critically, how they respond during adverse weather conditions.

Hydrodynamics is the field of tire engineering that relates to the way fluids flow through tire treads. Tire treads can be designed to direct fluids away from the tire path, which reduces the risk of hydroplaning. CFD creates accurate models of how fluids behave under tire treads so that engineers can improve performance for various weather conditions.

3. Cabin Comfort.

Airflow through a vehicle plays an important role in passenger comfort. However, ensuring that air circulates through the cabin in the right direction at sufficient flow rates is a complex problem. Warm and cold air behave differently, the position and angling of air vents is a significant factor, as is the shaping of the ducts leading up to the vents, and that of the cabin interior. Finally, demister vents are a critical component of driver safety, serving to keep the windshield free of fog and ice.

Fine-tuning each of these vents under a range of use cases would be difficult to accomplish by prototype. But CFD simulations can run dozens of tests in short timeframes, allowing designers to experiment with more layouts without the expense of physical models.

4. Electric drive engineering.

As electric vehicles form a larger share of the automotive industry, CFD applications for these specific use cases will become increasingly important. CFD is used to model lubrication of the gearbox, thermal transfer, and the flow of liquid coolants.

CFD also has applications in noise mitigation, ensuring the components of the electric engine operate silently and efficiently, within the structural housing.

5. Battery thermal management.

As electric vehicles take up a larger portion of the automotive market, the batteries which power them are subject to increasing levels of engineering scrutiny. Improvements to the functioning of a car battery can have significant consequences to the car’s design, affecting performance, sustainability, and price.

Current flow in batteries generates heat inside the battery cells, which has consequences for battery performance. Proper thermal management not only improves performance, it can extend the life of the battery. CFD models how a battery design manages heat transfer during regular use, as well as under exceptionally hot or cold environmental conditions.

CFD simulations boost innovation and lower production costs.

Of course, there are many other areas in automotive manufacturing where CFD can be applied. In fact, CFD has applications for any part of a vehicle that interacts with fluids, including the fuel tank, fluid lines, and radiators.

CAE simulations provide insight into product design and functionality that engineers need to push designs to higher peaks of performance. With the analysis provided by CFD, manufacturers and suppliers in the automotive sector will be able to better engineer solutions to serve their customers.

CATI has experience working with automotive manufacturers as CFD consultants. We also are licensed value-added resellers of CAE simulation software from Dassault Systèmes, including the XFlow and PowerFLOW CFD solutions. If you would like to learn more about starting a CFD project with us or about the software support our engineering team can provide, contact us.