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Sail towards a ecological marine future


In early 2023, the International Maritime Organization (IMO) set ambitious targets to achieve a ecological marine industry and net-zero emissions by 2050, a dramatic acceleration from the previous target of 2100. The industry has been sailing in rough seas since then, with widespread implications for the life cycle management of ships, from concept design to in-service operation and decommissioning. Most industry stakeholders anticipated this development, having observed the sequence of progressively stricter environmental regulations.



During the Clean Energy Action Forum 2022, American Bureau of Shipping (ABS) CEO and President Chris Wiernicki outlined so-called credible fuel pathways, which will be the main driver in ship operators' selection of new fuel types to meet zero carbon targets. The technological readiness schedule is at the heart of decision-making, which can be divided into short, medium and long-term periods. According to Wiernicki, such readiness is given if the following four pillars can be established:


  • A solid business case

  • Scalability

  • Provision and use of certifiable data

  • Mitigation of unintended consequences


Short-term solutions for a ecological marine industry


Short-term solutions are liquefied natural gas (LNG), methanol and first and second generation biofuels. According to Clarksons, 4.1% of the world's commercial fleet can use LNG as fuel. This represents 91% of the total share of the fleet capable of alternative fuels. Furthermore, the dominance of LNG is reflected in the current order books, with 33.3% opting for LNG, followed by Liquefied Petroleum Gas (LPG) with 2.3%, methanol (1.2%), ethane (0.3%) and hydrogen (<0.3%). %). Orders combining LNG with the “ammonia ready” option represent up to 10% of these orders. The main incentive for using biofuels is that the existing fuel infrastructure requires few or no adjustments. For smaller, short-sea and coastal vessels, suitable battery solutions are already available, and successful prototypes of fully electric and autonomous vessels can be referenced.


Liquefied natural gas (LNG) tanker


Medium-term solutions


The medium-term period will see further methanol advancement, with ammonia rising, as compatible engines become more available over the next two years.


Long-term projection


In the long term, green fuels (fuel produced from biomass sources through various biological, thermal and chemical processes) will be available alongside blue hydrogen, i.e. hydrogen produced from natural gas and supported by capture and carbon storage (CCS). CCS technology readiness is crucial both onboard and ashore. Classification societies are leading the way in evaluating nuclear power as an option for large commercial ships that can accommodate the technology.


Simcenter simulation chain – setting sail


Each step of the journey to achieving the net zero goal brings distinct engineering challenges to the ship's operation; to name a few:


  • Gas dispersion

  • After treatment

  • Swinging in tanks

  • Tank boiling (process of unwanted temperature increase in tanks that compromises the cryogenic state of the gas).

  • Post-treatment to reduce and remove emissions (purifiers)

  • Cryogenic gas leaks during refueling (refueling process)

  • Trip planning – fuel generation and emissions profiles


Simcenter STAR-CCM+'s multiphysics capabilities for hybrid multiphase modeling are being leveraged to provide simulation-based predictions for these problems in both concept design and forensic analysis.




At a higher systems level, Simcenter Amesim enables analysis of engine and propulsion configurations with varying levels of detail and fidelity, extending to trip planning, fuel consumption and emissions profiles.


Simcenter Amesim


The first coastal ships are already sailing completely electric, while the nautical industry has begun to embark on its electrification mission. Simcenter Amesim, Simcenter Motorsolve and Simcenter STAR-CCM+ offer many standardized solutions to consider battery pack sizing, powertrain design or help prevent thermal runaway.


Uncontrolled battery – Simcenter CFD simulation


Big ships, zero emissions, ecological marine solutions


Turning to the larger ships and workhorses of global commerce, we want to focus on how Simcenter suite simulation technology is helping engineers address short- and medium-term solutions for alternative fuels. Among the four pillars of viable fuel pathways, when it comes to ammonia, mitigating unintended consequences must be addressed early in implementation.


LNG and ammonia are stored in a cryogenic state, which means that any exposure to environmental conditions, for example through leaks during fueling, will lead to instantaneous vaporization (flash boiling), putting the crew at risk and presenting numerous environmental hazards . The sudden boiling of liquid spray from a leaking pipe into the environment occurs because the ambient pressure is below the saturation pressure of the liquid fuel. Depending on the direction of the spray and the distance from adjacent structures, dispersed vapor cloud precipitation may occur: the impact of liquid droplets remaining from the spray, mostly vaporized, and therefore highly flammable.



Case Study: Bunkering


Fueling is a critical operation on board ships at sea or in port. Successful fueling requires the safe transfer of fuel to the ship's tanks without overfilling, spills or leaks.


Simulation can help in the first stages of the supply process


At the beginning of the fueling process is planning the trip to determine the amount of fuel to be supplied. Simcenter Amesim's marine library allows you to connect your engine and powertrain model to the voyage and maneuver simulation environment, accounting for hotel loads, auxiliary engine fuel consumption, wind, waves, and current effects on power characteristics.





After determining the amount of fuel, including the reserves to be filled, planning begins as to which tanks will receive the fuel. Here, a model of the tanks, pipes and valves, ballast system and fuel intake through the supply itself is essential for predicting and monitoring performance and ensuring the desired hydrostatics of the ship. These items and action plans for leaks or spills are typically discussed at the pre-bunker conference – which can be digitally supported by rapid time models for quick responses to what-if scenarios.


The key to success


The Simcenter Flomaster simulation environment allows you to generate result envelopes for different supply scenarios, but can also be used upstream in the design phase to size pumps and lines to achieve the ideal time for filling, emptying and sounding tanks. Ultimately, critical metrics from the simulation can be automatically entered into the petroleum ledger in accordance with MARPOL Annex I.



Avoid possible system failures and hazards


The interest now is in possible system failures and dangers to the crew and the environment. Models can be configured to produce explicit responses to relevant regulations, for example IMO IGC and IGF codes for LNG. LNG is generally stored at around -162°C and presents cryogenic hazards such as frostbite and human skin burns, and fire and explosion risks during the transition to a gaseous state within the flammable range. In the case of ammonia, skin burns, irritation and inflammation of the crew's respiratory system and eyes may occur. High concentrations of gas in the air, especially in confined spaces, can lead to explosions or fatal results to human life.



Learn how CFD simulation can help you analyze unintended consequences


To better understand the dangers of flash spray boiling and gas dispersion, we analyzed the problem of refueling at sea, where we simulated the cryogenic dispersion of ammonia from a tube due to a leak during fueling. Using simulations with Simcenter STAR-CCM+, the complex physics of the instantaneous boiling of cryogenic gas dispersion can be studied. Metrics sought include the extent of the plume, the concentration of ammonia at certain points and whether or not rain will occur. While outdoor deck workers are unlikely to be exposed to fatal concentration levels exceeding 2,000 ppm for 30 minutes or more, stinging or burning sensations in the eyes and respiratory system may occur from exposure to as little as 70 ppm above. in the same time frame, according to the National Institute of Health.


These levels are not unattainable within closed rooms such as engine compartments, which highlights the importance of employing simulation technology for risk assessment and countermeasure design.



In our fictional supply scenario, liquid ammonia was discharged from a leak horizontally in the receiving vessel's supply infrastructure at a pressure of 8 bar, causing rapid dispersion into the environment. Over the course of 10 seconds, approximately 1 ppm can be measured in typical locations for work operations. No rain was detected on the deck, that is, the entire leaked mass passed into a gaseous state.


Stay integrated – all hands on deck for a ecological marine future



In this post, engineering problems related to ecological marine targets were presented, from conceptual design to onboard operation and assisting in the generation of mandatory documentation. There will certainly be implications of your specific component or problem studies for fundamental aspects of overall ship design. In the likely event that you become overwhelmed by the complexity and interconnectivity of spanning the design space, Simcenter HEEDS will provide nautical reference points for port solutions.


Reveal the ultimate solution: Leverage your insights for the best results


The role of Simcenter HEEDS is twofold. On the one hand, its workflow manager acts as a spider in the web of Simcenter CAE tools through real-time I/O mapping and administration. Additionally, its multidisciplinary design optimization can be leveraged in the subtool, holistic process, or a combination of both. Setting realistic optimization constraints and leveraging the powerful Simcenter HEEDS post-processing suite to gain key insights will be critical to a safe return to port.


Time to anchor


There is an ocean of engineering problems when it comes to the design and operation of ships and floating platforms, and Simcenter has many more tools available than those mentioned in the blog in question. Have you ever wondered about the safety and comfort of passengers on your speedboat? Simcenter Madymo is the beacon to follow.


Move full steam ahead towards your ecological marine future using performance engineering integrated with Simcenter.


 

If you are navigating towards a sustainable future in the maritime industry, it is time to act. CAEXPERTS is here to help you chart your course toward short, medium and long-term solutions for greener shipping. Join us for a strategic conversation about the challenges and opportunities that await, and discover how we can help you successfully navigate this new landscape. Schedule your meeting with us now and prepare for a journey towards a more sustainable future for our industry.



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