From Navier-Stokes to NASCAR: How Roush Yates Engines Boosts Performance With CFD

MIA Member Convergent Science has shared the following news article.

From Navier-Stokes to NASCAR: How Roush Yates Engines Boosts Performance With CFD

It’s hard to beat the thrill of a NASCAR race. The roaring of engines as cars careen around the track as mere blurs, the deafening cheers of the fans, the animated voices of the announcers booming over the din. The atmosphere is electric, and excitement is palpable in the air as cars flash across the finish line.

Guided by the deft hands of the drivers, the race cars are propelled by powerful engines to mindboggling speeds—exceeding 200 mph on some tracks. The engine is the heart of the car, and it can easily make or break a race. Even minor tweaks to the engine can provide the small boost of power needed to best the competition.

Figuring out what tweaks to make, however, is not always easy. Exploring many different designs can be expensive, not just in terms of money, but also time—and time is a highly valued commodity in the racing world. With dozens of races each season, and each one in need of a specialized engine, being able to efficiently assess different design options is key.

Roush Yates Engines designs, tests, and builds purpose-built race engines for the NASCAR Cup Series and the NASCAR Xfinity Series. Founded in 2004 and headquartered in North Carolina, Roush Yates is the exclusive engine builder to Ford Performance. With nearly 400 wins across the two NASCAR series, Roush Yates is regularly powering cars to victory and championships. So how do they do it? In addition to state-of-the-art test facilities and a team of brilliant engineers and technicians, incorporating advanced modeling software like CONVERGE into their design process is one of their key strategies for winning.

Design Considerations

Designing racing engines is obviously a different beast than designing engines for everyday passenger vehicles. Each engine must be tailored to the specific tracks where it will be raced, with the goal of eking out every bit of performance possible. To achieve this, you need to consider a variety of factors, including the length of the track (typically ranging from 1/2 mile to over 2 miles), the vehicle traction available, differences in driver style, climate conditions, and even elevation.

“It’s very interesting to design for those types of different environments to make sure we’re doing the most we can to bring the best engine we can to each track,” says Jamie McNaughton, Technical Director at Roush Yates Engines.

Power isn’t the only necessity in a racing engine, either; the engines also need to be durable. While these engines won’t be racking up hundreds of thousands of miles, they need to be at peak performance while being driven under extreme conditions for up to three races and numerous practice sessions, which can add up to some 1,500 miles. All the power in the world won’t help you win if your engine breaks down mid-race!

So, you need performance, reliability, and durability. No pressure, right? Now add in the fact that you’re also working on a very short timeline. While the design cycle for a passenger vehicle engine might be on order of three years, in the NASCAR world, you’re working with timelines as short as 8-12 months. And there’s a lot that needs to be packed into those months, from planning and analysis to testing and production—any tools that can help speed up your design process can be a major advantage.

The Role of CFD

So how does Roush Yates leverage CFD in their engine design process?

Per the rules of NASCAR racing, manufacturers are working with homologated parts, i.e., parts that have been officially approved by the organization. Manufacturers can tweak these parts, but they can’t go off and make something brand new. That means that Roush Yates’ engineers are working within well-defined boundaries to try to find minor modifications that result in small but meaningful gains in power and performance.

This is where CFD shines. “Finding the last 0.5% that we’re looking for requires comprehensive 3D modeling,” says Jamie.

Roush Yates uses CONVERGE to model a variety of powertrain components, including intake manifolds, cylinder head ports, exhaust systems, intake systems, and cooling systems. To improve the engine’s gas exchange process, they use CONVERGE to analyze intake manifold flow losses, tune the manifold, and model the exhaust systems. Furthermore, they conduct cooling system evaluations to ensure that the coolant flow rate and system pressure are correct for the engine specifications and the tracks being raced.

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