Rudder blade with flow guiding side plates
By setting a guide plate at the trailing edge of the rudder blade, the vortex shedding point and wake interference are changed, solving the problem of vortex-induced vibration of traditional rudder blades and improving safety and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CSSC STARRY ENERGY SAVING TECH (SHANGHAI) CO LTD
- Filing Date
- 2023-05-25
- Publication Date
- 2026-06-26
AI Technical Summary
Traditional rudder blade designs are prone to vortex-induced vibration, which affects ship maneuverability and safety. Furthermore, existing frequency avoidance methods carry the risk of resonance and uncertainties related to structural changes.
Symmetrical guide plates are installed at the trailing edge of the rudder blade. Through the interference effect of the guide plates, the vortex shedding point and wake interference are changed, which hinders the generation of Karman vortex street and avoids vortex-induced vibration.
It effectively avoids vortex-induced vibration, improves ship navigation safety and propulsion efficiency, and reduces drag without changing the overall structure of the rudder blade.
Smart Images
Figure CN116513437B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ship rudder design, and more particularly to a rudder with a guide vane. Background Technology
[0002] In the design phase of some large ships, the design of the rudder must not only meet the ship's maneuverability requirements, but also consider the coordination between the rudder and the hull and propeller to reduce drag and improve propulsion efficiency. In order to increase the ship's propulsion efficiency, the rudder design is becoming thinner and thinner, which increases the risk of vortex-induced vibration at the trailing edge of the rudder blade. Vortex-induced vibration of the rudder blade can cause low-cycle fatigue failure, thereby affecting the ship's maneuverability and endangering the lives of the crew.
[0003] The excitation frequency of vortex shedding at the trailing edge of the rudder blade is related to the ship's speed. During operation, the ship's speed range varies greatly, resulting in a wide bandwidth for the excitation frequency of vortex shedding. If the natural frequency of the rudder blade is to be increased by improving its own stiffness, thereby avoiding the frequency forbidden zone of vortex-induced vibration, the cost would be very high. Moreover, the shape and size of the rudder blade are also subject to overall maneuverability requirements and cannot be changed arbitrarily.
[0004] The generation of vortex-induced vibration is closely related to the Kármán vortex street. Therefore, we should start by changing the way the Kármán vortex street is generated at the trailing edge of the rudder blade to avoid the formation of a regular, staggered vortex combination at the trailing edge of the rudder blade.
[0005] Traditional rudder blades feature a monotonous, smooth transition at the trailing edge, which does not alter the directionality or periodicity of the vortex motion, and the wake does not deflect. Instead, a regularly arranged, staggered vortex pattern forms at the trailing edge, generating a Karman vortex street. This causes coupled vibration between the fluid and the rudder blade, resulting in vortex-induced vibration. Traditional rudder blade trailing edge designs do not consider preventing vortex-induced vibration; the profile only needs to meet maneuverability requirements, and the plate thickness only needs to meet relevant strength requirements. Summary of the Invention
[0006] The purpose of this invention is to provide a rudder blade with a guide side plate, which can effectively avoid vortex-induced vibration and improve the safety of ship navigation.
[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:
[0008] A rudder blade with guide side plates is provided with two guide side plates at the trailing edge of the rudder blade. The two guide side plates are respectively provided on the two sides of the rudder blade and are symmetrically arranged on the rudder blade. The guide side plates are arranged along the trailing edge of the rudder blade, and the plate surface of the guide side plate is opposite to the side surface of the rudder blade. The guide side plates are spaced apart from the rudder blade.
[0009] Furthermore, the guide plate is fixedly connected to the side surface of the rudder blade via a series of connecting plates.
[0010] Furthermore, the series of connecting plates are evenly and discretely distributed along the trailing edge of the rudder blade, and the connecting plates are arranged in a horizontal state.
[0011] Furthermore, the flow guide side plate is streamlined.
[0012] Furthermore, the connecting plate is streamlined.
[0013] Furthermore, the distance between the guide plate and the trailing edge of the rudder is taken in the range of 200-300mm; the distance between the upper end of the guide plate and the upper edge of the rudder is taken in the range of 0-200mm; the distance between the lower end of the guide plate and the lower edge of the rudder is taken in the range of 0-200mm; the width of the guide plate is taken in the range of 500-800mm; and the thickness of the guide plate is taken in the range of 6-10mm. The clearance between the guide plate and the rudder is set to the width of the rudder at the front end of the guide plate.
[0014] Furthermore, the rudder blade is used in container ships, liquefied natural gas carriers, bulk carriers, or warships.
[0015] The rudder blade of the present invention can effectively avoid the occurrence of vortex-induced vibration. The principle is as follows: In the rudder blade, a guide plate is provided at the trailing edge of the rudder blade. The guide plate can form a beneficial interference to the vortex shedding at the trailing edge of the rudder blade. Under the interference of the guide plate, the point of emergence of the wake vortex at the trailing edge of the rudder blade will move forward and leave the rudder blade from the position of the guide plate. The wake formed will also interfere with the vortex that originally appeared from the trailing edge of the rudder blade, causing the wake vortex to no longer periodically cross from the trailing edge of the rudder blade, thereby eliminating the Karman vortex street at the trailing edge of the rudder blade and avoiding the occurrence of vortex-induced vibration.
[0016] Compared with the prior art, the rudder blade of the present invention has the following advantages: symmetrical guide side plates are provided at the trailing edge of the rudder blade. Under the guiding effect of the guide side plates, the vortex shedding effect at the trailing edge of the rudder blade will interfere with each other, which can hinder the generation of Karman vortex street, thereby avoiding vortex-induced vibration, preventing uncontrollable situations during ship navigation, improving the safety of ship navigation, and without changing the overall structural design of the rudder blade, making it easy to implement. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the rudder blade with a flow guide side plate of the present invention;
[0018] Figure 2 This is a schematic diagram of the transverse cross-section of the rudder blade of the present invention;
[0019] Figure 3 for Figure 2An enlarged schematic diagram of the trailing edge of the rudder blade. Detailed Implementation
[0020] The present invention will be further illustrated below with specific embodiments:
[0021] This embodiment provides a rudder blade with a guide side plate for use on container ships. This rudder blade can effectively avoid vortex-induced vibration and improve the safety of ship navigation.
[0022] In other embodiments, the rudder blade can also be used on other vessels, such as liquefied natural gas carriers, bulk carriers, and other civilian vessels and warships.
[0023] See Figure 1 and Figure 2 ,
[0024] The most significant feature of the rudder blade 1 in this embodiment compared to a conventional rudder blade is that it has two guide side plates 2 at its trailing edge. These two guide side plates 2 are elongated and are respectively disposed on both sides of the rudder blade 1. Furthermore, the two guide side plates 2 are symmetrically arranged on both sides of the rudder blade 1, and the guide side plates 2 are arranged along the trailing edge of the rudder blade 1 (or, the central axis of the length direction of the guide side plates 2 is parallel to the trailing edge of the rudder blade 1). Moreover, the plate surface of the guide side plates 2 is opposite to the side surface of the rudder blade 1, and the guide side plates 2 and the side surface of the rudder blade 1 are separated by a gap.
[0025] In this embodiment, the gap between the guide plate 2 and the rudder blade 1 is referred to as the guide gap.
[0026] Specifically
[0027] For a single guide plate 2, it is fixedly connected to the side surface of the rudder blade 1 by a series of connecting plates 3.
[0028] More specifically,
[0029] The series of connecting plates 3 are fixedly connected to the side surface of the rudder blade 1 by welding. The series of connecting plates 3 are evenly and discretely distributed along the trailing edge of the rudder blade 1. Then, the flow guide plate 2 is welded together with the series of connecting plates 3, thereby realizing the fixed connection between the flow guide plate 2 and the rudder blade 1.
[0030] It should be noted that the space between two adjacent connecting plates 3 constitutes a small gap between the guide side plate 2 and the rudder blade 1. All the "space between two adjacent connecting plates 3" together constitute the guide gap between the guide side plate 2 and the rudder blade 1.
[0031] It should be noted that all the connecting plates 3 are set horizontally so that the water can flow smoothly through the guide gap between the guide side plate 2 and the rudder blade 1.
[0032] The guide plate 2 is designed in a streamlined shape, and all the connecting plates 3 are also designed in a streamlined shape so that the water flow can smoothly pass over the surface of the guide plate 2 and the connecting plates 3.
[0033] See Figure 3 ,
[0034] In this embodiment,
[0035] The axial distance between the guide side plate 2 and the trailing edge of the rudder blade 1 can be in the range of 200 to 300 mm;
[0036] The length of the guide plate 2 can be determined based on the distance between it and the upper and lower edges of the rudder blade 1. The distance between the upper end of the guide plate 2 and the upper edge of the rudder blade 1 can be taken in the range of 0 to 200 mm, and the distance between the lower end of the guide plate 2 and the lower edge of the rudder blade 1 can be taken in the range of 0 to 200 mm.
[0037] The width of the flow guide side plate 2 can be in the range of 500mm to 800mm, and the thickness of the flow guide side plate 2 can be in the range of 6mm to 10mm.
[0038] The clearance between the guide plate 2 and the rudder 1 ( Figure 3 The b2 indicator is set to "width of the rudder at the front end of the guide plate 2" ( Figure 3 (b1 instruction location).
[0039] The rudder blade of this embodiment can effectively avoid the occurrence of vortex-induced vibration. The principle is as follows: A guide plate 2 is provided at the trailing edge of the rudder blade 1. The guide plate 2 can form a beneficial interference to the vortex shedding at the trailing edge of the rudder blade 1. Under the interference of the guide plate 2, the point where the wake vortex appears at the trailing edge of the rudder blade 1 will move forward and leave the rudder blade from the position of the guide plate 2. The wake formed will also interfere with the vortex that originally appeared from the trailing edge of the rudder blade, causing the wake vortex to no longer periodically cross from the trailing edge of the rudder blade, thereby making the Karman vortex street at the trailing edge of the rudder blade disappear and avoiding the occurrence of vortex-induced vibration.
[0040] The technical solution of this embodiment no longer uses the traditional frequency avoidance method and does not require strengthening the rudder blade structure. The existing traditional method is frequency avoidance. If the method is to reduce the eddy current shedding frequency instead of increasing the stiffness of the rudder blade itself, it is also necessary to increase the diameter of the trailing edge round steel, making the size of the round steel very large.
[0041] Increasing the eddy current shedding frequency carries significant uncertainty, as the increased excitation frequency may resonate with the second and third modes of the rudder blade. While methods to reduce eddy intensity and eddy excitation force by interfering with the wake vortex can reduce eddy current strength, the rudder blade will still exhibit a large response when resonance is induced by the Kármán vortex street, and this does not fundamentally solve the problems caused by the Kármán vortex street.
[0042] This invention fundamentally eliminates the generation of the Kármán vortex street, rather than mitigating its adverse effects. Traditional frequency avoidance methods still carry the uncertainty of resonance, but this invention, by resolving the excitation source, eliminates the risk of resonance. Furthermore, the disappearance of the Kármán vortex street reduces drag and improves propulsion efficiency.
[0043] In the rudder blade of this embodiment, the guide plate 2 provided at the trailing edge can effectively increase the lateral flow interception volume, thereby improving the ruddering efficiency.
[0044] In summary, in the rudder blade of this embodiment, symmetrical guide plates 2 are provided at the trailing edge of the rudder blade 1. Under the guiding effect of the guide plates 2, the vortex shedding effect at the trailing edge of the rudder blade 1 will interfere with each other, thus hindering the generation of Karman vortex street, thereby avoiding vortex-induced vibration, preventing uncontrollable situations during ship navigation, improving the safety of ship navigation, and without changing the overall structural design of the rudder blade, which is easy to implement.
[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A rudder blade with a guide vane, characterized in that: Two guide plates (2) are provided at the trailing edge of the rudder (1). The two guide plates (2) are respectively provided on the two sides of the rudder (1) and are symmetrically arranged on the rudder (1). The guide plate (2) is arranged along the trailing edge of the rudder (1), and the plate surface of the guide plate (2) is opposite to the side of the rudder (1). The guide plate (2) and the rudder (1) are separated by a gap. The guide plate (2) is fixedly connected to the side surface of the rudder (1) by a series of connecting plates (3); The series of connecting plates (3) are evenly and discretely distributed along the trailing edge of the rudder blade (1), and the connecting plates (3) are set in a horizontal state; The distance between the guide side plate (2) and the trailing edge of the rudder (1) is taken in the range of 200-300mm; The distance between the upper end of the guide plate (2) and the upper edge of the rudder (1) is taken in the range of 0 to 200 mm, and the distance between the lower end of the guide plate (2) and the lower edge of the rudder (1) is taken in the range of 0 to 200 mm. The width of the flow guide plate (2) is taken in the range of 500 to 800 mm, and the thickness of the flow guide plate (2) is taken in the range of 6 to 10 mm.
2. The rudder blade with a guide vane according to claim 1, characterized in that: The flow guide side plate (2) is streamlined.
3. The rudder blade with a guide vane according to claim 1, characterized in that: The connecting plate (3) is streamlined.
4. The rudder blade with a guide vane according to claim 1, characterized in that: The clearance between the guide side plate (2) and the rudder (1) is set as the width of the rudder at the front end of the guide side plate (2).
5. The rudder blade with a guide vane according to claim 1, characterized in that: The rudder (1) is used on container ships, liquefied natural gas carriers, bulk carriers or warships.