Marine engineering and shipbuilding
Marine engineering and shipbuilding is an industry that has existed for centuries, which includes the design, construction, and maintenance of ships and other vehicles used for transportation on water. Since ancient times, transportation by sea has played an important role for humans because most of the earth’s surface is covered by water, and for transporting cargo between countries and continents, due to the high cost of air transportation, the best and cheapest option for us is shipping by sea. In addition to transportation on the surface of the waters, during the First World War, governments thought of navigating the waters through subsurface movement for safety. which led to the construction of submarines, which is one of the components of the naval power of any country, its subs.
Therefore, the development of this industry is important for engineers. In this article, we will introduce marine engineering and shipbuilding and discuss some CFD applications in the design and development of shipbuilding and marine engineering in general.
Marine engineering has various trends, of which the shipbuilding industry is one of its trends. Shipbuilding is an essential part of the marine engineering field, which includes the construction and development of ships and submarines and light and heavy floats from raw materials such as steel and wood. And aluminum.
Marine engineering examines the process of designing, building, and maintaining ships and other marine vessels used for water transportation. Marine engineers are responsible for developing the systems that make a ship function properly, while shipwrights are responsible for building the ship itself. Technological advances have made marine engineering and shipbuilding increasingly important in recent years, leading to the construction of more efficient ships for unique and more optimal needs, requiring less expense and carrying heavier loads than before. In addition, today’s marine engineers can use computer-aided design (CAD) and computational fluid dynamics (CFD) analysis software to create more complex and practical designs. In the past, this was not possible for engineers.
The future of marine engineering and shipbuilding looks bright with continuous advancements in computer-aided design and analysis software that allows us to build better ships faster than ever, leading to more optimal designs. And reduce the cost of maintenance of vessels to a much greater extent. Marine engineering is an efficient field in today’s society because we need to design faster ships with excellent safety to meet the needs of today’s human society in water transportation.
Application of CFD in marine engineering
Most engineering problems with boats, ships, and submarines are related to water flow. Aero-Hydrodynamics Forces on these vehicles play the most important role in designing their appearance and performance. These forces are also the main forces on sails and propellers, which are among the tools of propulsion systems. Internal combustion engines, air conditioning, piping systems, gas, oil, and condensate charging and discharging facilities and procedures (in tankers and ships, including gas tanks) are also important engineering issues in shipbuilding industries. The common denominator of all these problems is the presence of fluid and its flow, and as a result, it will be obvious to use computational fluid dynamics tools, CFD, to solve them. In general, CFD applications in shipbuilding and submarine construction industries can be introduced in the following areas.
CFD analysis in aero-hydrodynamics
The most important design parameter of all surface and subsurface water transport vehicles is affected by the simultaneous application of wind and water forces on their bodies. In such problems, the priority is the simulation of incompressible, two-phase, and turbulent flows. However, the simulation of the above flow regimes and the solution of six degrees of freedom equations for boats and ships are also much more complete and highly recommended. In summary, the most important CFD applications in this field are:
The simulation and solution of the flow field in the two-phase physics of weather and air, which is true in all vessels, can be used to calculate the force from the fluid side to the vessels and small sailing and motor ships or large cargo ships and These forces can be drag force or lift force or buoyancy force. These forces are the main design parameters in the body of small and large vessels.
In addition, when the weather is stormy and intense winds blow, or when a storm and enormous waves collide with ships, the main issue is the stability of vessels and ships to prevent them from sinking. CFD can also help us in investigating this phenomenon. Also, by solving the air flow field on sailing vessels, we can measure the propulsive force provided by the sails and find out about their functional conditions and correctness. We can also optimize the sails with more targeted simulations to achieve higher propulsion forces.
We also know that submarines are underwater for most of their working time, so the physics of single-phase water flow is important. We can calculate drag and buoyancy forces by simulating the flow around submarines. Another challenge that is very important in the design of subsurface vessels is the pressure caused by the water column on the vessel’s body. CFD can help us investigate this issue.
Rudders are blades installed at the end of ships and float for steering and maneuverability. Checking the performance of this equipment in different working conditions is very important for ship designers; since the laboratory solution is costly and time-consuming, CFD methods are the best option for designing and checking the performance of these vanes.
We know that cargo ships are one of the most important vessels carrying cargo using containers. Increasing the number of containers on ships can increase the drag force on the vessel due to the increase in contact surface with airflow, which will also change the stability of the ship’s buoyancy. With CFD, we can check these changes and prevent accidents from happening.
CFD analysis in the propulsion system
Ships with fossil fuel engines account for most of the vessels in the world. Boats and sailing vessels are also in second place in abundance, and the number of ships equipped with nuclear fuel is also high. Of course, electric motors are also used in submarines. The applications of CFD in all fossil fuel-based and most nuclear fuel engines are similar to their application in piston engines. Among other essential applications of CFD in the propulsion system of boats, ships, and submarines, the following can be mentioned:
• Optimizing the shape, dimensions, and arrangement of sails to achieve the highest aerodynamic efficiency
• Simulating, studying, and checking the performance of the propellers of the engines in different working conditions
• Simulating and investigating the effects of cavitation on the corrosion and lifespan of the propellers
• Optimizing the design of ships’ chimneys in the type of emission of exhaust gases from their engines
CFD analysis in facilities
The facilities of a giant ship are as comprehensive, diverse, and scattered as the facilities of a city. The flow of different fluids affects these facilities, which include various flow regimes such as multi-phase, turbulent, porous areas, circulation, and many other cases. Due to the extensiveness of the details, only the headings of CFD applications in ship and submarine installations and air conditioning are limited here.
• Simulation of airflow and calculation of wind forces on masts and cranes in the main deck of the ship
• Simulating, studying, and checking the performance of different parts of desalination systems
• Simulation, study, and investigation of the fire, smoke emission, and fire spread
• Simulating, studying, and checking the performance of fire extinguishing systems
• Simulation, study, and investigation of piping, water supply, sewage, and sewage treatment systems
• Simulating, studying, and checking the filling and emptying of oil, gas, and condensate tanks in ships carrying oil, condensate, and gas materials.
• Simulating, studying, and investigating turbulence in the fuel tank of ships, submarines, and tanks containing oil, gasoline, and condensate in vessels carrying oil and condensate.
• Simulating, studying, and checking the performance of air conditioning on the lower deck of the ship
• Simulating, studying, and checking air conditioning performance in the bridge room.
• Simulating, studying, and checking the performance of air conditioning in passenger and crew cabins
• Simulating, studying, and checking the performance of air conditioning in public places such as restaurants and halls
• Simulating, studying, and checking the performance of air conditioning in engine houses