Leveraging cross-domain simulation to realize a high-performance, sustainable vessel design

Meeting the demand for enhancements

Wärtsilä Corporation (Wärtsilä) is a Finnish company that is a global leader in innovative technologies and lifecycle solutions for the marine and energy markets. It supplies innovative, sustainable and high-performance, next-generation propulsion systems for large-scale vessels such as bulk carriers and cruise ships to high-speed ferries. Wärtsilä equipment is used on over 41,500 vessels worldwide.

Although its existing equipment provides superior performance, there is an ongoing demand to provide enhancements, especially with the latest tightening of emissions regulations by the International Marine Organization (IMO), which is striving for net-zero greenhouse gas emissions by 2050. Starting in 2023, the Energy Efficiency Existing Ship Index (EEXI) required owners to optimize the performance of existing vessels. This is in addition to carbon intensity integrators (CII) regulations already in effect in 2023 and the European Union Emissions Trading system (ETS) regulations set for 2024. Clearly, the global marine sector is focused
on reducing emissions and continually improving efficiency.

“Emission regulations are becoming more stringent and rightfully so,” says Petra Stoltenkamp, product performance manager at Wärtsilä. “When it comes to vessel design and integration issues, we are leading the way to better emissions performance thanks to our holistic approach.

“From the propulsion side, there are so many variables to consider when seeking to become more sustainable: fleet management and route optimization, new technology like
wind-assisted, hybrid and electrified propulsion while keeping in mind the biggest variable of all – sea conditions.”

The team has considerable experience simulating sea conditions. Over 25 years ago, Wärtsilä adopted computational fluid dynamics (CFD) simulation to replace physical towing tank testing. Today, thanks to the extensive use of Simcenter™ STAR-CCM+™ software for CFD and Simcenter Amesim™ software for system simulation, the team can incorporate extra layers of critical hydro-dynamic performance information into its design process and engineering decisions, including ship speed, resistance, propeller performance, etc.

Traditionally, complex CFD models were used to develop propulsion systems. The marine industry was focused on speed and overall performance; in other words, how fast could you get your tanker, cruise ship or mega container ship from points A to B. This has all changed with the new regulations; now engineers need to know how the propeller system performs in various conditions and operation scenarios. Every bit of data and information counts and can make the difference between an efficient and sustainable solution and one that falls short.

"Our CFD work in Simcenter STAR-CCM+ provides excellent engineering details, but we realized we needed something more – another way from the start to rapidly handle all those hydrodynamic and other performance elements,” says Stoltenkamp. “This was when we started co-simulating with Simcenter Amesim.”

Simcenter is part of the Siemens Xcelerator business platform of software, hardware
and services.

“Our Simcenter CFD simulation is very important, it’s still the starting point to create a baseline,” says Stoltenkamp. “But we also needed an efficient solution to consider other factors and performance conditions and see how the propeller was reacting. This is where our co-simulation tool was vital. We could even integrate some customer feedback into the loop at an early stage – which is a real competitive advantage.”

“One of the key issues still today in the marine industry is the holistic approach to vessel design,” says Norbert Bulten, who is also a product performance manager for Wärtsilä. “For the most part, everybody is doing their own thing and then the integrator is performing magic to get it all to work together. With so many suppliers, engineers, naval architects, designers and partners working on a single vessel, a holistic perspective early in the engineering process is the only way to gain real insight into vessel performance and make better, more sustainable decisions earlier in the design process.”

Enhancing dynamic positioning capability

One example of the importance of using Simcenter co-simulation was being able to simulate the dynamic positioning capability of a vessel. Consisting of a complex computer-controlled system of sensors, propellers and thrusters, a dynamic positioning system allows a vessel to maintain a constant position during all types of conditions, including rough seas and high wind and waves. The dynamic positioning (DP) capability indicates up to what condition a vessel can keep constant position to perform its operation. It is especially useful for drill ships or wind turbine installation vessels (WTIVs) when the ship needs to stay at a specific location no matter what the circumstances.

“Way before the keel laying ceremony, you need to design all sorts of systems that affect overall performance,” explains Stoltenkamp. “The dynamic positioning is one of these components in the overall performance. This is where we can step in using Simcenter for a cross-domain simulation. It helps us design exactly what we need from a performance standpoint.

A new customer-centric tool

As simulation pioneers, especially in the CFD field, Bulten, Stoltenkamp and their team realized they could enhance their holistic engineering approach and develop a customer engagement tool leveraging the power of a cross-domain simulation.

The team started working on the system level by selecting classic CFD performance criteria like resistance, ship speed and propulsion methods and automated them using a few variables in Simcenter Amesim. Using the Simcenter WebApp Server, the team developed an in-house tool called OPTI-DP™ to make system-level simulation available to everyone in the process from cross-domain Wärtsilä project engineers to the customer’s technical experts.

“Thanks to our Simcenter tools, we can innovate and learn so much about the real performance of our products,” says Stoltenkamp. “But not everyone is a CFD specialist, so we needed to develop an easy-to-access tool that contained all the Simcenter simulation information. We wanted to show the benefits of a design change or invention in a language that our customers understand. This resulted in our OPTI-DP engagement tool™.

“Our sales teams really appreciate this as well. They can work with the customer to customize the vessel early on and find solutions to current problems and challenges.”

“Our web-based OPTI-DP tool basically combines the results from the two Simcenter software packages to get a reasonable ‘yes’ or ‘no’ answer within seconds,” explains Bulten. “You can see where to make the best possible trade-offs without taking days to rework a complex CFD model.”

Stoltenkamp adds: “Our OPTI-DP tool enhances not only our internal cross-domain team discussions, but also discussions with our customers. With this tool, we can propose more sustainable solutions to our customers in seconds on the stationary vessel design. It is an excellent example of the power of system-level simulation.”

Innovation meets customer expectations

Wärtsilä acknowledges systems-level work in the early development stages has been a success factor. Not only are decisions easier and cheaper to make, but the insights gained can lead to inventions, innovative solutions and increased customer satisfaction.

Sustainable alternatives

This way of working isn’t just for power and dynamic positioning capability: The team at Wärtsilä also uses it to characterize all types of equipment, including new hybrid systems, electric propulsion and wind-assisted propulsion, a technology still in its infancy.

“We use this tool internally as well to work with different teams so we can build a complete ship with the best configuration for thruster placement,” says Bulten. “Not only are we meeting the customer’s performance targets, but we also immediately see where we can save on fuel consumption by 10 or even 20 percent. This is a significant environmental savings and is very attractive commercially.

“Working on the entire digital twin with the customer is our focus. We no longer look at what our product does individually, but instead look at how can we improve the complete vessel design and get the best solution overall.”

Looking into the future

Wärtsilä is focusing on using the OPTI-DP web application to further enhance performance. They plan to expand their system-level simulation approach into other areas of ship development, including maneuvering and system integration, and using a digital twin to continually push sustainability and the decarbonization progress to contribute to a more sustainable marine sector.