boat propeller

Abstract

A marine propeller comprises a propeller hub and blades evenly distributed on the circumference of the propeller hub. The propeller hub is shaped like a waist drum. The contour of the blade surface of each blade is formed by a hyperbola convex guiding edge, a hyperbola concave following edge and a circumferential arc edge in an enclosing mode. According to the blade surfaces of the blades, the arc chord length gradually increases from the position with the distance 0.2-0.8 times of the radius of the propeller, reaches the maximum value in the position with the distance 0.8 times of the radius of the propeller and slightly decreases from the position with the distance 0.8-1.0 times of the radius of the propeller; according to the shape of the cross section of each blade, the cross section, from the root of the blade to the position with the distance 0.2 times of the radius of the propeller, of the blade is round, and the cross section, from the position with the distance 0.2 times of the radius of the propeller to the position with the distance 1.0 times of the radius of the propeller, of the blade is an oval with the long axis gradually increasing and the short axis gradually decreasing ; the angle alpha of pitch of each blade ranges from 10 degrees to 25 degrees. The marine propeller is suitable for providing bidirectional power for moving forward and backward of a ship, can also make a double-propeller ship change a left propeller and a right propeller and has the advantage of being high in working efficiency.

Description

technical field [0001] The invention relates to a marine propeller. Background technique [0002] A marine propeller is a device that provides power for ships to sail, usually consisting of a hub and 3-6 blades evenly distributed along the circumference of the hub. The outline of the hub of a traditional marine propeller is a cone whose generatrix is ​​convex and arc-shaped, with a large head and a small tail. If the big end cuts water, the resistance will be large and eddy currents will easily occur; Different, the water cutting on both sides has different hydraulic characteristics, so it is difficult for this kind of propeller to form reverse power, and the left and right propellers cannot be interchanged; the blade surface of the blade is from 0.2 times to 0.65 times the propeller radius, and the arc chord length gradually increases The propeller is large and has a wide blade width. In this range, the propeller is not able to enter the water smoothly, and it is easy to g...

AI Technical Summary

Problems solved by technology

The outline of the hub of a traditional marine propeller is a cone whose generatrix is ​​convex and arc-shaped, with a large head and a small tail. If the big end cuts water, the resistance will be large and eddy currents will easily occur; Different, the water cutting on both sides has different hydraulic characteristics, so it is difficult for this kind of propeller to form reverse power, and the left and right propellers cannot be interchanged; the blade surface of the blade is from 0.2 times to 0.65 times the propeller radius, and the arc chord length gradually increases The propeller is large and has a wide blade width. In this range, the propeller is not able to enter the water smoothly, and it is easy to generate eddy currents and form cavitation, which intensifies the metal corrosion caused by the cavitation of the propeller and the vibration of the hull caused by the uneven rotational force. From 0.65 times to 1.0 times the propeller radius, the arc chord length gradually decreases, and as the arc chord length gradually decreases, the blade area also decreases, making the water drainage here weak, making it difficult to improve the efficiency of the propeller

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