Optimizing moon pool design and performance with advanced simulation engineering

Delivering complex solutions

How to design a hole in a boat is certainly not the first thing that springs to mind when you talk about naval architecture and marine engineering. But when you are designing 100-meter drill ships, high tech fall-pipe vessels or marine research boats that need direct access to the ocean floor, that is a different story.

So what does a drill ship or fall-pipe vessel have in common with a marine research boat? The answer: a moon pool. A moon pool is an opening in the hull that gives access to the water below. In the case of marine research vessels, it allows technicians and researchers to lower scientific equipment and even submarines directly into the ocean. In the case of drilling vessels, a moon pool takes the grunt work out of advanced geotechnical projects. With a drill tower and moon pool, drilling vessels can perform drilling and subsea well services directly from the bottom of the vessel. For fall-pipe vessels like the Simon Stevin, the moon pool provides a way to deposit rock via a long pipe directly on the seabed, which is useful for activities such as land reclamation and port infrastructure work.

A moon pool is an innovative design concept and being a hole in a boat, one that can cause some performance issues as well. Designing and engineering an effective moon pool requires sophisticated simulation, including computational fluid dynamics (CFD) and optimized design.

This is where Vuyk Engineering Rotterdam (Vuyk) excels. The firm specializes in complex maritime engineering projects, such as finding design and engineering solutions for high tech performance issues, providing tailor-made vessel designs and conversions as well as equipment design and marine operations engineering. With years of marine engineering experience, the Vuyk specialists have engineered some of the most complex and highly technical solutions for leading shipbuilders and marine industry players around the globe.

Specialized yet flexible

As a supplier to numerous shipyards and marine customers, Vuyk has the in-house expertise to work with a variety of specialized software tools for stability calculations, structural engineering, multibody and hydrodynamic simulation as well as standard computer-aided design (CAD) solutions. The team also uses in-house developed software and customized spreadsheets and calculations, which is still typical in the marine industry.

Enter the CFD experts

Optimizing a moon pool design means finding the right balance between hundreds of possibilities, including customer specifications, cost options and various performance factors. And since moon pools are usually one-of-a-kind, these can differ greatly from vessel to vessel. Moon pools can typically cause issues such as unwanted water flows, increased resistance, increased fuel consumption and additional turbulence. The team at Vuyk realized that they had to cover a lot of angles to engineer a moon pool properly so they decided to launch a study using HEEDS™ software.

One of the CFD specialists on the Vuyk team had already worked on optimizing a specific moon pool design for a drilling vessel using Simcenter™ STAR-CCM+™ software, an integrated solution for CFD-focused multiphysics simulation. HEEDS and Simcenter STAR-CCM+ are part of the Siemens Xcelerator business platform of software, hardware and services. After completing five simulation studies, the specialist managed to take the resistance level of the moon pool on the vessel’s hull down by 2.4 percent. But looking at the big design picture, one of his colleagues realized that with the right tool they could bring it down even more. That tool turned out to be HEEDS.

Using HEEDS to explore solutions

HEEDS is design space exploration software that interfaces with all types of CAD and commercial computer-aided engineering (CAE) packages as well as in-house and customized tools. Since HEEDS is focused on efficiently exploring various solutions and assessing performance according to final design objectives, it seemed to be an excellent tool for the challenge. HEEDS provides a big picture overview of the engineering work and various software packages and tools and is used to optimize the overall design and engineering process. In other words, it can enhance the quality of engineering no matter what tools or solutions are used.

From good to great engineering

Knowing that there was room for improvement, the team used HEEDS to investigate further. Running a design exploration loop in HEEDS revealed better design options, trimming the overall resistance by more than 1 percent from the previous resistance level.

Decreasing resistance by more than 3 percent can mean a lot for huge drilling and fall-pipe vessels and exploration ships. It translates into an immense fuel savings and overall annual cost reduction of potentially millions of euros – not to mention the environmental impact of not burning all that fossil fuel.

“Using HEEDS doesn’t necessarily save time,” says Erwin Put, director of operations, Vuyk Engineering Rotterdam. “It’s the quality of the engineering and final design that results in big-picture savings like less fuel consumption, lighter overall design and better structural performance.”

Achieving the optimal design

He adds, “HEEDS can handle optimization across all kinds of software packages, including nonstandard and our in-house tools. These in-house tools and the knowledge that comes with them are an important competitive advantage for us.”

This optimization means the best-possible design is achieved within the time and budget constraints of a project, which is always the challenge at Vuyk.

“Our customers set the technical specifications,” says Put. “We work within these boundaries according to a specific budget and timeline. It is our goal to come up with the best possible solution within those boundaries. The marine industry is still an extremely customer-centric and customized industry. You have to understand the huge amount of capital invested in a single vessel project. The customer has a wish list when it comes to performance. By the time we come into the picture, our time and budget is limited.”

Quality engineering provides a competitive advantage

Time and budget issues will always be there, but using quality optimization techniques like HEEDS means that Vuyk isn’t competing on price or an hourly rate; they are competing on the quality of the engineering they deliver and the time it takes them to do it.

“Working with HEEDS requires a different mindset as an engineer,” says Put. “You need a big picture view as an engineer. You need to think about the whole design and where it would work best to apply certain improvements.

“HEEDS allows you to innovate more and gives you better insight into the design. Our team makes the right trade-offs to get to the best-possible design. HEEDS is an excellent tool to help really understand the issues. But you need to know your design goal and what exactly you are trying to optimize. It doesn’t work miracles. You need quality input to get the right results and get to the best possible design.”