Marine propeller cap turbine with end plates on fin tips

Abstract

The marine propeller cap turbine with the end plate on the fin tip comprises a propeller cap turbine body, a propeller and a connecting structure, and six evenly-distributed fin blades are arranged on the propeller cap turbine body; the tip part of each fin is provided with an end plate opposite to the rotating direction; the connecting structure comprises twelve bolts which are used for fixedly connecting the propeller cap turbine body with a propeller hub of a propeller, and the circumferential installation position of the propeller cap turbine can be adjusted at will. According to the propeller cap turbine with the fin tip provided with the end plate, for a ship running on a ship route, the mode of installing the propeller cap turbine behind the propeller is an energy-saving mode capable of effectively saving oil consumption, and the problems that according to traditional propeller cap turbine design, the relative position between the fin blades and the propeller blades needs to be considered, certain difficulty and risks are brought to design and installation, and the design cost is lowered are solved. And the blade tip of the traditional fin blade discharges, so that the vortex energy recovery capability of the fin blade is reduced, and the synergistic effect is not obviously improved.

Description

Technical Field

[0001] The present invention relates to the field of ship propulsion devices, and particularly to a propeller cap turbine with fin tips and end plates for a propeller hub, which improves the energy-saving effect by optimizing the fin layout and end plate structure. Background Art

[0002] The rotational torque generated by the fuel consumption of the inboard main engine of the ship causes the propeller to rotate behind the ship. The blades on the propeller hub absorb the rotational force and convert it into a linear propulsion force, thereby driving the ship to overcome the frictional resistance and move forward.

[0003] The propeller rotates at high speed behind the ship and pushes the ship forward. A large amount of eddy currents will be generated at the propeller hub position. The eddy currents extend from the propeller hub and propeller cap to the rear of the propeller, which will consume the power of the main engine and cause energy loss. There are various ways to eliminate the eddy currents at the propeller hub. The propeller cap turbine is one of the more effective ones. By arranging fins on the propeller cap, the eddy currents generated by the propeller are scattered so that they no longer extend and develop, thereby achieving the purpose of saving the power of the main engine. The propeller cap turbine also absorbs the energy of the eddy currents, causing the fins to generate a certain thrust. The thrust acts on the propeller hub through the propeller cap, which can improve the operating efficiency of the propeller and achieve the purpose of increasing efficiency. Through the above two mechanisms, the propeller cap turbine can prompt the ship to reduce energy consumption and improve the operating efficiency of the propeller.

[0004] Conventional propeller cap turbines have some inherent problems in terms of installation and energy-saving mechanisms. First of all, the number of fins of the propeller cap turbine generally corresponds to the number of propeller blades, that is, a 4-blade propeller corresponds to 4 fins. When designing and installing, special attention needs to be paid to the relative position of the fins and the propeller blades. Often, a large number of design verifications are required to achieve the optimal effect. There is also a risk of deviation and error during installation, which affects the energy-saving effect. Secondly, the tip of the traditional propeller cap turbine fin discharges fluid, and the flow fields on the front and back of the fin exchange at the tip. On the one hand, this causes a certain degree of fin tip eddy currents to be generated by the propeller cap turbine itself. On the other hand, it will cause incomplete absorption of the propeller eddy current energy, and the generated fin thrust is not obvious, affecting the efficiency improvement effect.

[0005] Traditional propeller cap turbines usually use the same number of fins as the propeller (e.g., a 4-blade propeller corresponds to 4 fins), and need to be installed strictly aligned to avoid performance loss (such as CN208036573U), resulting in high design complexity and easy errors. In addition, the problem of fluid discharge at the tip of the traditional fin is significant, which is prone to generating secondary eddy currents and reducing the energy recovery efficiency. Although prior art such as CN217754065U has improved the connection structure, it has not solved the problems of fin layout and tip flow field control. Summary of the Invention

[0006] To solve the technical problems existing in the traditional propeller cap turbine, the present invention proposes a marine propeller cap turbine with fin tips and end plates.

[0007] To achieve the above object, the technical solution of the present invention is: a propeller cap turbine with end plates at the fin tips for marine use, including a propeller cap turbine body, a propeller and a connection structure. Six evenly distributed fin blades are provided on the propeller cap turbine body; end plates opposite to the rotation direction are provided at the tips of each fin blade; the connection structure includes 12 bolts for fixedly connecting the propeller cap turbine body and the hub of the propeller, and the circumferential installation position of the propeller cap turbine can be adjusted arbitrarily.

[0008] Further, the end plates extend radially along the fin blades, and the length is 4%-6% of the diameter of the propeller cap turbine body;

[0009] Further, the maximum chord length of the fin blades is 30%-34% of the diameter of the propeller cap turbine, and the maximum thickness is 5%-7% of the maximum chord length.

[0010] Further, the pitch angle of the fin blades is the same as the pitch angle at 0.7R of the propeller, where R is the radius of the propeller.

[0011] Further, the extending direction of the end plates is opposite to the rotation direction of the propeller, and the thickness of the end plates is 20%-30% of the maximum thickness of the fin blades.

[0012] Further, the airfoil of the fin blades is a NACA0016 symmetric airfoil.

[0013] Further, the diameter of the propeller cap turbine body does not exceed 28% of the diameter of the propeller.

[0014] Further, the bolt holes of the connection structure are the same as the bolt holes at the small end of the hub of the propeller, and the circumferential distribution angles can be freely matched.

[0015] Further, the roots of the fin blades and the propeller cap turbine body are fixed by integral casting or welding.

[0016] Further, the end edges of the end plates are streamlined rounded corners, and the radius of the rounded corners is 2%-4% of the length of the end plates.

[0017] The beneficial effects of the present invention are:

[0018] A propeller cap turbine with end plates at the fin tips proposed by the present invention. For ships operating on routes, installing a propeller cap turbine behind the propeller is an energy-saving method that can effectively save fuel consumption. It solves the problem that the traditional design of the propeller cap turbine needs to consider the relative position between the fin blades and the propeller blades, which brings certain difficulties and risks to the design and installation, and the tip leakage of the traditional fin blades reduces the ability of the fin blades to recover the eddy current energy, resulting in an insignificant improvement in the efficiency enhancement effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an assembly drawing of the propeller cap turbine, the propeller and the bolts;

[0020] Figure 2 is the three-dimensional view of the marine fin-tip with end-plate propeller cap turbine of the present invention;

[0021] Figure 3 is the schematic diagram of a single propeller cap turbine fin blade (including the smooth cap);

[0022] Figure 4 is the rear view of the propeller cap turbine;

[0023] Figure 5 is the side view of the propeller cap turbine;

[0024] Figure 6 is the connection bolt diagram of the propeller cap turbine and the propeller. Specific embodiments

[0025] The present invention will be further described below in conjunction with the drawings and embodiments.

[0026] As Figure 1 , as shown in Fig. 6, a marine fin-tip with end-plate propeller cap turbine of the present invention mainly includes 1 propeller cap turbine 1, a propeller 2, and 12 bolts 3 (for connecting with the propeller). During installation, first confirm that the small end of the propeller 2 has 12 bolt holes, and confirm that the bolt hole specifications are the same as those on the propeller cap turbine 1. Align the bolt holes on the propeller cap turbine 1 with those on the propeller 2, and the circumferential position can be adjusted arbitrarily. Connect and fix the propeller 2 and the propeller cap turbine 1 through 12 bolts 3 to ensure that the propeller 2 and the propeller cap turbine 1 rotate together, so that the propeller cap turbine 1 can play an energy-saving role.

[0027] A 6-blade fin-tip with end-plate propeller cap turbine of the present invention, as Figures 2 to 5 shown, 6 fin blades 4 can cover the entire surface of the propeller cap turbine 1 without increasing torque consumption. As Figure 4 shown, during design, only the pitch angle of the fin blades needs to be ensured, and there is no need to pay extra attention to the circumferential relative position between the fin blades 4 and the propeller blades. Similarly, during installation, there is no need to consider the circumferential installation angle either, which reduces the installation difficulty and avoids the risks of misalignment and incorrect installation. End plates 5 in the opposite direction of the rotation direction are arranged at the fin tips of the fin blades 4. On the one hand, the fin-tip end plates 5 can isolate the flow field exchange at the tips, prevent the generation of disturbing eddies at the tips of the propeller cap turbine 1, and reduce energy loss; on the other hand, the end plates 5 can significantly reduce the tip leakage flow, keep the high-pressure field always in the fin tip region, thereby enhancing the efficiency of the propeller cap turbine in recovering the propeller hub vortex, increasing the thrust of the propeller cap turbine, and improving the efficiency enhancement effect. Increase the chord length at the fin tips of the fin blades to further increase the thrust range and improve the effect.

[0028] As Figure 2As shown in the figure, a 6 - blade propeller - cap turbine with end plates. The maximum diameter of the propeller - cap turbine 1 should not exceed 28% of the corresponding propeller diameter. The maximum chord length of the fin blade 4 should be 32% of the propeller - cap turbine diameter. The maximum thickness of the fin blade 4 is 6% of the maximum chord length. The airfoil of the fin blade is selected as NACA0016. The pitch angle is the same as the pitch angle at 0.7R of the propeller, where R is the propeller radius. The protruding length of the fin - tip end plate 5 is 5% of the propeller - cap turbine 1 diameter. The diameter of the propeller - cap body is the same as the small - end diameter of the propeller hub. The length of the propeller - cap body is determined by the arrangement of the fin blades.

[0029] As Figure 3 shown, a single propeller - cap turbine fin blade (including the smooth cap). Through Figure 3 it can be seen that there is an end plate at the tip of the propeller - cap turbine fin blade, which is opposite to the rotation direction. The end plate can prevent the tip leakage, isolate the flow - field exchange, and play a role in increasing thrust and reducing eddy currents. The length of the end plate should not be too long, otherwise the strength is difficult to guarantee. The protruding length is based on 5% of the propeller - cap turbine diameter.

[0030] Example 1: During installation, the propeller - cap turbine is fixed to the propeller hub with 12 M20 bolts, and no circumferential alignment is required. The pitch angle of the fin blade is set as the pitch angle at 0.7R of the propeller (such as 15°), and the length of the end plate is 5% (25 mm) of the propeller - cap diameter (500 mm). Tests show that the eddy - current energy recovery efficiency is increased by 12%, and the main - engine fuel consumption is reduced by 0.35%.

[0031] Example 2: The thickness of the end plate is 25% (7.5 mm) of the maximum thickness of the fin blade (30 mm), and the diameter of the propeller - cap turbine is set as 25% (500 mm) of the propeller diameter (2 m). Through flow - field simulation, the end plate effectively inhibits 90% of the tip leakage, and the thrust increases by 8%.

[0032] The innovation points of the fin - tip with - end - plate propeller - cap turbine of the present invention:

[0033] 1. In the prior art, the fin and the propeller blade need to be aligned (the included angle is 17° - 18°). The present invention cancels the alignment requirement and realizes full - circumference coverage through a 6 - blade layout.

[0034] 2. An end - plate structure is added to solve the problem of traditional fin - tip leakage.

[0035] 3. The prior art relies on the connection of hexagonal inserts. The present invention adopts a standardized bolt - hole design, which has strong adaptability and is convenient for maintenance.

[0036] 4. Through the geometric optimization of the end plate, the thrust - increasing effect is significantly higher than the 0.75 - pitch design of the prior art.

[0037] The technical effects of the fin - tip with - end - plate propeller - cap turbine of the present invention:

[0038] 1. The installation error tolerance is improved, and the manual adjustment time is reduced by more than 50%.

[0039] 2. The eddy current energy recovery efficiency is increased by 10%-15%, and the host fuel consumption is reduced by 0.3%-0.5%.

[0040] 3. The end plate structure enables the thrust gain to reach 5%-8%, and extends the service life of the propeller.

[0041] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be realized that all the equivalent replacements and obvious changes made by using the description and illustration content of the present invention should be included in the protection scope of the present invention.

Claims

1. A propeller cap turbine with an end plate for a marine fin tip, comprising a propeller cap turbine body, a propeller and a connecting structure, characterized in that: The propeller cap turbine body is provided with 6 evenly distributed fins; the tip of each fin is provided with an end plate opposite to the rotation direction; the connection structure includes 12 bolts for fixing the propeller cap turbine body to the propeller hub, and the circumferential installation position of the propeller cap turbine can be adjusted arbitrarily.

2. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The end plate extends radially along the fin blade, and the length thereof is 4%-6% of the diameter of the propeller cap turbine body.

3. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The maximum chord length of the fin blade is 30%-34% of the diameter of the propeller cap turbine, and the maximum thickness is 5%-7% of the maximum chord length.

4. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The pitch angle of the fin blade is consistent with the pitch angle of the propeller at 0.7R, where R is the radius of the propeller.

5. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The extending direction of the end plate is opposite to the rotating direction of the propeller, and the thickness of the end plate is 20%-30% of the maximum thickness of the fin blade.

6. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The fin blade airfoil is a NACA0016 symmetrical airfoil.

7. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The diameter of the propeller cap turbine body does not exceed 28% of the propeller diameter.

8. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The bolt holes of the connection structure have the same specifications as the bolt holes at the small end of the propeller hub, and the circumferential distribution angles can be freely matched.

9. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The root of the fin blade is fixed to the propeller cap turbine body by integral casting or welding.

10. The propeller cap turbine with end plate for marine fin tip according to claim 1, characterized in that: The end edge of the end plate is a streamlined fillet, and the fillet radius is 2%-4% of the length of the end plate.

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