Tuesday, June 8, 2010

Propeller design looks simple yet a complicated task

Learning to design propeller can be a boring subject for any engineering students. Propeller does not experience revolution in design just like computer software and other multi-media gadgets. Ship propeller, although located below the sea surface and unseen by people, in fact, plays very important role in propelling the ship throughout all of her service life. Propeller usually consists of between three to six blades that rotate around the propeller shaft. These blades suck water and push them back. As a result the displaced water creates reaction that push the ship forward. This is a simple Newton' action-reaction law. The law sounds simple but the design of the propeller is more complicated than that.
During the stages of propeller design, a designer or naval architect must understand resistance and propulsion theories of a ship, the performance of propellers working in open water and behind the hull as well as a lot of  formulas and charts related to standard propeller series.
As someone who studies marine screw propeller and ship propulsion, I can say this is one of the most complicated subjects which I have ever read when studying in naval architecture.
Computer has greatly revolutionized various fields of engineering yet the water flow behind a ship's hull, through, and around the propeller is far more complicated to be simulated on the computer screen. Every propeller has its own performance characteristic when rotating behind a ship's hull. Today, it is only higher efficiency that propeller designer has to achieve. Vibration has to be minimized to ensure that passengers can enjoy their sea voyage well. by Charles Roring