JPS59153689A - Boat propeller - Google Patents

Abstract

PURPOSE:To improve the efficiency of a propeller which consists of a plurality of vanes by making them differ from each other in a part or all of the conditions of pitch, radius, area ratio and rake angle. CONSTITUTION:A propeller consists of four propeller vanes A to D. The vanes A and C have the same conditions of radius, pitch and area ratio. Similarly, the vanes B and D have the same cinditions described above. Each of the vanes A and C and each of the other vanes B and D have the conditions of the radius, the pitch and the area ratio set approximately 80%, approximately 75% and 20%, respectively. Then the vanes A and C may generate 80% of the total thrust while the vanes C and D may generate 20% thereof. In addition, a propeller corresponding to that having the arbitrary number of vanes may be designed by appropriately changing each of the combinations of said conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of screw propellers that are generally used as propellers for ships. The purpose of this invention is to provide a marine propeller capable of exerting vibration excitation force.

Generally, screw propellers are often used as marine propulsors, and currently, four-blade propellers and six-blade propellers are most commonly used.

However, the aforementioned 4-blade and 6-blade propellers are ``symmetrical blade type'' propellers configured under the same conditions for the container, in other words, the propeller blade diameter, pitch, area ratio, or rake angle. It is.

However, in recent years, there has been a strong demand for energy-saving measures, and even for this type of propeller, there is a desire to further improve propeller efficiency.

In order to improve the efficiency of the propeller's propeller, the aforementioned ``symmetrical wing type propeller'' reduces the number of propeller blades or reduces the blade area ratio. For example, the vibrational force of the propeller is ``As the propeller rotates in the complicated water flow near the stern, the force that the propeller blades receive from the fluid fluctuates while the propeller rotates.'' This fluctuating force is transmitted to the hull, causing the hull to vibrate. This causes problems such as deterioration of habitability and damage to hull components.This fluctuating force acting on the propeller is called propeller excitation force.''As a result, vibrations at the stern of the ship continue to pose problems for the stability of the ship. There is. For this reason, in conventional commercial ships, four-blade propellers or six-blade propellers have often been applied as part of the solution to this type of problem. When designing this type of propeller, various propellers with energy-saving measures have been proposed and put into practical use.As an example, recently, a three-blade propeller with a completely reduced number of blades has been proposed. The symmetrical -7%ll propeller is being applied.

However, even with the above-mentioned "three-blade symmetrical propeller", the ability can only be demonstrated within the pre-designed range of various capacities (propeller efficiency, propeller excitation force), and the number of blades in between No comparable propeller efficiency was obtained.

The present invention was invented in view of the above-mentioned circumstances, and is an intermediate number of blades among the two-blade, four-blade, or six-blade propellers currently in practical use, in other words, two to three blades. ,
It is a marine propeller that can achieve a propeller efficiency corresponding to an intermediate number of blades such as 3 or 4 blades, and a propeller excitation force of -2m. Its characteristics are the pitch of 6 blades in a multi-blade propeller, Some or all of the conditions of the diameter-to-area ratio or the rake angle are configured to be different.

The present invention will be described in detail below based on drawings of embodiments.
The graph shown in the figure shows the change in propeller efficiency when the total number of blades is changed for a symmetrical blade type propeller obtained from the MAU type propeller design chart. wings and 6 wings and 6
The efficiency of the propeller made up of the blades is shown in the same graph η. (chain line)
Therefore, if you want to obtain propeller efficiency equivalent to the intermediate blade of the 4-blade or 6-blade propeller that is currently widely used, for example, 4 or 5 blades, the blade diameter, pitch, area ratio, or rake It can be understood that this can be achieved by designing the entire propeller under different conditions for part or all of the angle.

Specifically, as shown in the embodiment (propeller model diagram) in FIG. 2, in a four-blade propeller having four propeller blades A, B, C, and D, the blades A, C, and B The conditions for the propeller blades in which the blades and the D blades are all paired are symmetrical blades, that is, the blade diameter, pitch, and area ratio of the blades are the same.

1! The conditions for IJ, A wing and C wing are the same, and the conditions for Bj, l and Dvg are the same, and A
, c3i; (For B and D blades, the conditions of propeller blade diameter and i° latch area ratio are approximately 80%, approximately 75 inches,
It is set at about 60%. This results in a propeller efficiency equivalent to 80% of the total thrust for the p, p, and C wings, 20% of the total thrust for the B and D wings, and a propeller efficiency equivalent to 2.5 wings.

Propeller excitation force can be changed.

Furthermore, by changing the combination of diameter, pitch, area ratio, and rake, it is possible to design a propeller with any real number of blades.
A propeller with the highest propeller efficiency can be achieved at the limit of propeller excitation force where vibration is not a problem.

The above example is an example of the present invention, and each condition and propeller blade control can be set at the appropriate time to achieve propeller efficiency and propeller excitation force in accordance with the purpose. You can win.

As described above, the present invention is configured so that some or all of the conditions of the blade diameter, pitch, area ratio, or rake angle of a marine propeller are set to be different.
It is possible to obtain various performances of the intermediate blade that could not be obtained with conventional propellers, and it is highly practical as a propeller as part of energy saving for ships.

Note that the embodiment shown in FIG. 2 is one embodiment of the present invention, and the present invention is not limited to this embodiment.

[Brief explanation of drawings]

The graph in FIG. 1 is a graph showing changes in the number of propeller blades and the propeller efficiency, and FIG. 2 is an fflW diagram showing one embodiment of the propeller of the present invention. Patent author Kobe Steel, Ltd.

Claims (1)

[Claims] A marine propeller having a plurality of blades, characterized in that the propeller blades are configured such that some or all of the conditions of pitch, diameter/area ratio, or rake angle are different.