Inlet flow channel design method, inlet flow channel and ship water jet propulsion device

Abstract

The invention belongs to the technical field of ship water jet propulsion devices, and discloses an inlet flow channel design method, an inlet flow channel and a ship water jet propulsion device. The inlet flow channel design method comprises the following steps that S1, one inlet flow channel is designed, and a horizontal straight pipe section, an arc bent pipe section and an inclined straight pipe section of the inlet flow channel are sequentially arranged; s2, a transition pipe section of the inlet flow channel in the step S1 is arranged, an arc part and a spline part are arranged on the first side, one end of the arc part is made to be tangent to an inclined straight pipe section on the first side, and the two ends of the spline part are made to be tangent to the arc part and a ship bottom plate correspondingly; a first rounding part and a second rounding part are arranged on the second side to form a lip, the first rounding part is tangent to the inclined straight pipe section, and the second rounding part is tangent to the ship bottom plate. And the radiuses R2 of the arc parts of the inlet flow channels are kept consistent, and the heights H0 of the lips are kept consistent. By means of the inlet flow channel design method, the inlet flow channel can be suitable for grids of the same specification.

Description

Technical Field

[0001] This invention relates to the field of ship waterjet propulsion technology, and in particular to an inlet flow channel design method, an inlet flow channel, and a ship waterjet propulsion device. Background Technology

[0002] Waterjet propulsion is a power system that propels a ship forward by spraying high-speed water jets to generate reaction force. Its core principle is to convert the mechanical energy of the engine into the kinetic energy of the water flow, thereby achieving efficient propulsion. It is widely used in various high-performance ships and shallow-draft vessels. Typically, when ships are navigating for extended periods in inland waterways or coastal waters with high levels of debris, a grating needs to be installed in the inlet channel of the waterjet propulsion system to prevent debris from entering the propulsion system. If the ship is navigating for extended periods in clean water or requires high-speed navigation, the grating can be removed to avoid affecting speed. The detachable grating design allows the ship to adapt to different operating environments.

[0003] In modern ship design, hull forms exhibit highly differentiated characteristics, including flat-bottomed vessels (such as inland waterway barges) and deep-V-shaped vessels (such as high-speed patrol boats). The inlet channels of each pump in a waterjet propulsion system are jointly designed based on the hull bottom profile and the geometric parameters of the inlet channels. This requires that the center positions of the lips of different longitudinal sections of the inlet channels be consistent with the distance from the hull bottom, and that the back profile be tangent to the hull bottom. For flat-bottomed vessels, this design ensures that the center positions of the lips of different longitudinal sections of the inlet channels are in the same plane, and that the back profiles of different sections remain consistent, meaning that the grid interfaces of the inlet channels can be guaranteed to be consistent. However, for deep-V-shaped vessels, existing inlet channel designs do not have the center positions of the lips of different longitudinal sections on the same horizontal plane, and the back profiles are also inconsistent. If multiple pumps are installed, each pump's inlet channel requires a separately designed grid, resulting in high costs.

[0004] Therefore, there is an urgent need to propose an inlet flow channel design method, an inlet flow channel, and a ship waterjet propulsion device to solve the above problems. Summary of the Invention

[0005] The first objective of this invention is to provide an inlet flow channel design method for designing and installing inlet flow channels for various spray pumps of a ship's waterjet propulsion device on the ship's bottom plate. This method enables the inlet flow channels to be applicable to the same specification of gratings and to the design and installation of inlet flow channels for spray pumps of different ship types.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] An inlet flow channel design method is used to design inlet flow channels for each pump of a ship's waterjet propulsion device on the ship's bottom plate. Multiple inlet flow channels are spaced laterally on the bottom plate and aligned longitudinally. The total length L and characteristic diameter D of each inlet flow channel are consistent. The inlet flow channel design method includes the following steps:

[0008] S1: The horizontal straight pipe section, the arc bend pipe section and the inclined straight pipe section of the inlet flow channel are arranged in sequence, such that the horizontal straight pipe section and the inclined straight pipe section are tangent to both ends of the arc bend pipe section, and the side of the inlet flow channel away from the bottom plate is the first side, and the side of the inlet flow channel facing the bottom plate is the second side.

[0009] S2: A transition pipe section for the inlet flow channel is provided. An arc-shaped portion and a spline portion are provided on the first side, such that one end of the arc-shaped portion is tangent to the inclined straight pipe section on the first side, and both ends of the spline portion are tangent to the arc-shaped portion and the bottom plate, respectively. A first rounded portion and a second rounded portion are provided on the second side to form a lip, such that the first rounded portion is tangent to the inclined straight pipe section on the second side, and the second rounded portion is tangent to the bottom plate.

[0010] The radius R2 of the arc portion of each of the inlet channels is kept consistent, and the height H0 of the lip is kept consistent.

[0011] As an optional technical solution for the inlet flow channel design method, the inlet flow channel design method further includes:

[0012] S3: In all longitudinal sections of the inlet channel, the height H0 of the lip, the radius R3 of the first rounded portion, and the radius R4 of the second rounded portion are all kept constant.

[0013] As an optional technical solution for the inlet flow channel design method, the inlet flow channel design method further includes:

[0014] S4: Connect the centers of the first rounded portions on all the longitudinal sections of the inlet channel with spline curves, and use the spline curves as trajectory lines to scan and set the reinforcing structure of the lip along the trajectory lines of the sector surface where the first rounded portions on the longitudinal sections are located.

[0015] As an optional technical solution for the inlet flow channel design method, the inlet flow channel design method further includes:

[0016] S5: In the inlet channel, the intersection of the inclined straight pipe segment on each longitudinal section and the first rounded portion is used as the first cutting point. The first cutting line formed by all the first cutting points and the first cutting surface formed by the vertical direction divide the lip into the first body and the first filling body.

[0017] The first connecting portion of the grille is made to have the same shape as the first filler so that the first connecting portion can be adapted to the first body. When the grille needs to be installed, the grille and the first body are connected with a first fastener; when the grille does not need to be installed, the first filler and the first body are connected with the first fastener to fill the position of the first connecting portion.

[0018] As an optional technical solution for the inlet flow channel design method, step S5 also includes:

[0019] Several first threaded holes are drilled in the same horizontal plane along a direction perpendicular to the first cutting surface, and the first threaded holes are drilled in conjunction with the first connecting part of the grid.

[0020] As an optional technical solution for the inlet flow channel design method, the inlet flow channel design method further includes:

[0021] S6: Using the same cutting method as in step S5, in the inlet channel, the intersection of the inclined straight pipe segment and the arc portion on each of the longitudinal sections is used as the second cutting point. The second cutting line formed by all the second cutting points and the second cutting surface formed by the vertical direction are used to cut the arc portion into the second body and the second filler.

[0022] The second connecting portion of the grille is made to have the same shape as the second filler so that the second connecting portion can be adapted to the second body. When the grille needs to be installed, the grille and the second body are connected with a second fastener; when the grille does not need to be installed, the second filler and the second body are connected with the second fastener to fill the position of the second connecting portion.

[0023] As an optional technical solution for the inlet flow channel design method, step S6 also includes:

[0024] Several second threaded holes are drilled in the same horizontal plane along a direction perpendicular to the second cutting surface. The second threaded holes are drilled in conjunction with the second connecting part of the grid.

[0025] A second objective of the present invention is to provide an inlet channel that can accommodate a removable grille of the same specification.

[0026] To achieve this objective, the present invention adopts the following technical solution:

[0027] An inlet flow channel is provided on the outer side of the bottom plate. The inlet flow channel is designed using the above-mentioned inlet flow channel design method. The total length L of each inlet flow channel on the bottom plate is equal, the characteristic diameter D of each inlet flow channel is equal, the radius R2 of the arc portion of each inlet flow channel is equal, and the height H0 of the lip of each inlet flow channel is equal.

[0028] As an optional technical solution for the inlet channel, the lip of the inlet channel includes a first body and a first filler that are detachably connected. The first filler is flush with the inner wall surface of the inlet channel, and the first connecting part of the grille has the same shape as the first filler so that the first body and the first connecting part are adapted to each other. The arcuate portion includes a second body and a second filler that are detachable. The second filler is flush with the inner wall surface of the inlet channel, and the second connecting part of the grille has the same shape as the second filler so that the second body and the second connecting part are adapted to each other.

[0029] A third objective of the present invention is to provide a ship waterjet propulsion device in which the inlet channels of multiple spray pumps are adapted to a grid of the same specification.

[0030] To achieve this objective, the present invention adopts the following technical solution:

[0031] A ship waterjet propulsion device includes multiple spray pumps, each of which is provided with the aforementioned inlet channel, which is installed on the outer side wall of the ship's bottom plate.

[0032] The beneficial effects of this invention are:

[0033] The inlet flow channel design method provided by this invention is used to design inlet flow channels for each pump of the ship's waterjet propulsion device on the ship's bottom plate. Multiple inlet flow channels are arranged laterally at intervals and aligned longitudinally on the bottom plate to ensure consistent water jetting from each pump. First, horizontal straight pipe sections, arc-shaped bend pipe sections, and inclined straight pipe sections are sequentially installed to complete the main body of the inlet flow channel. The tangential connection of each pipe section ensures a smooth and continuous inner wall surface of the inlet flow channel, reducing water flow resistance. Then, the transition pipe section of the inlet flow channel is set, with an arc section and a spline section on the first side. The arc section is tangent to the inclined straight pipe section for a smooth transition, and the two ends of the spline section are tangent to the arc section and the bottom plate, respectively, to complete the smooth transition between the back side of the inlet flow channel and the bottom plate. Since the position of each inlet flow channel on the bottom plate is different, the distance H between the axis of the inlet flow channel and the bottom plate may be different. Therefore, each inlet flow channel needs to be corrected with a different spline section to ensure a smooth transition between the back side of the inlet flow channel and the bottom plate. On the second side, a first rounded section and a second rounded section are set to form a lip, which completes the smooth transition between the inner side of the inlet flow channel and the bottom plate. Specifically, by keeping the radius R2 of the arc section of each inlet flow channel consistent and the height H0 of the lip consistent, the distance from the inner lip to the arc section of each inlet flow channel is consistent. This ensures that the installation position and installation space of the inlet flow channel grid are consistent, allowing inlet flow channels with different transition pipe section shapes to be adapted to the same specification of grid, i.e., suitable for universal grids.

[0034] This inlet flow channel design method only requires keeping the radius R2 of the arc portion of the inlet flow channel consistent and the height H0 of the lip consistent. It does not require considering the shape of the ship's bottom plate. Therefore, this inlet flow channel design method can be applied to the design and installation of the inlet flow channel of the spray pump on the bottom plate of different ship types. Attached Figure Description

[0035] Figure 1 This is a flowchart of the inlet flow channel design method provided by the present invention;

[0036] Figure 2 This is a profile drawing of the ship bottom plate provided by the present invention;

[0037] Figure 3 This is a schematic diagram of the arrangement of the spray pump provided by the present invention on the bottom plate of the ship;

[0038] Figure 4 This is a side view of the inlet flow channel provided by the present invention (only each pipe segment is shown);

[0039] Figure 5 This is a comparison diagram of the lip height of multiple inlet channels provided by the present invention;

[0040] Figure 6 This is an assembly drawing of the inlet flow channel and the bottom plate provided by the present invention;

[0041] Figure 7 yes Figure 6 A magnified view of a portion at point A;

[0042] Figure 8 This is an isometric view of the inlet flow channel provided by the present invention;

[0043] Figure 9 This is a cutting diagram of the inlet flow channel at the lip provided by the present invention;

[0044] Figure 10 This is a cross-sectional view of the inlet channel after lip cutting provided by the present invention.

[0045] Figure 11 This is a cut view of the inlet flow channel on the second side provided by the present invention;

[0046] Figure 12 yes Figure 11 A magnified view of the area at point B;

[0047] Figure 13 This is an assembly drawing of the inlet flow channel and the grille provided by the present invention;

[0048] Figure 14 This is a schematic diagram of the structure of the grille provided by the present invention;

[0049] Figure 15 This is an exploded view of the inlet flow channel after the grille has been removed, as provided in an embodiment of the present invention.

[0050] Figure 16 yes Figure 15 A magnified view of the area at point C;

[0051] Figure 17 yes Figure 15 A magnified view of a section at point E.

[0052] In the picture:

[0053] 1. Bottom plate; 10. Grating; 11. First connecting part; 12. Second connecting part; 100. Horizontal straight pipe section; 200. Circular arc bend pipe section; 300. Inclined straight pipe section; 400. Transition pipe section; 411. Circular arc part; 412. Spline part; 420. Lip; 421. Reinforcing structure; 431. First filler; 432. Second filler. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention and not the entire structure.

[0055] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0057] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0058] This embodiment provides an inlet flow channel design method, which is used to design and install the inlet flow channels of various spray pumps of the ship's waterjet propulsion device on the bottom plate. This method enables the inlet flow channels to be applicable to the same specification of grating and to the design and installation of inlet flow channels for spray pumps of different ship types.

[0059] Specifically, such as Figure 1 As shown, the inlet flow channel design method includes the following steps:

[0060] S0: Multiple inlet channels are arranged laterally on the bottom plate 1 and aligned longitudinally. The total axial length L and characteristic diameter D of each inlet channel are kept consistent, so that the water spraying of each spray pump is consistent.

[0061] S1: Begin designing one of the inlet channels, sequentially setting up a horizontal straight pipe section 100, a circular arc bend pipe section 200, and an inclined straight pipe section 300 for the inlet channel, so that the horizontal straight pipe section 100 and the inclined straight pipe section 300 are tangent to both ends of the circular arc bend pipe section 200, thus completing the main body of the inlet channel. The tangential connection of each pipe section makes the inner wall surface of the inlet channel smooth and continuous, reducing water flow resistance.

[0062] S2: A transition pipe section 400 for the inlet flow channel is provided. An arc portion 411 and a spline portion 412 are provided on the first side, so that one end of the arc portion 411 is tangent to the inclined straight pipe section 300 on the first side for a smooth transition. Both ends of the spline portion 412 are tangent to the arc portion 411 and the bottom plate 1 respectively, thus completing the smooth transition between the back side of the inlet flow channel and the bottom plate 1. Since the position of each inlet flow channel on the bottom plate 1 is different, the height H of the axis of the inlet flow channel (i.e., the distance between the axis position and the bottom plate 1) may be different. Therefore, each inlet flow channel needs to be corrected with a different spline portion 412 to make the back side of the inlet flow channel smoothly transition with the bottom plate 1. A first rounded portion and a second rounded portion are provided on the second side to form a lip 420. The first rounded portion is tangent to the inclined straight pipe section 300 on the second side, and the second rounded portion is tangent to the bottom plate 1. The smooth transition between the inner side of the inlet flow channel and the bottom plate 1 is completed through the lip 420. By ensuring that the radius R2 of the arc portion 411 of each inlet channel is kept consistent, and the height H0 of the lip 420 is kept consistent, the distance from the lip 420 to the arc portion 411 in each inlet channel is consistent. Consequently, the installation position and installation space of the grid 10 in the inlet channel are consistent, so that each inlet channel with a different shape of the transition pipe section 400 can be adapted to the same specification of grid 10, that is, it is suitable for universal grid 10.

[0063] The inlet flow channel design method only requires that the radius R2 of the arc portion 411 of the inlet flow channel be kept consistent, and the height H0 of the lip 420 be kept consistent. It does not need to consider the shape of the bottom plate 1. Therefore, the inlet flow channel design method can be applied to the design and installation of the inlet flow channel of the spray pump on the bottom plate 1 of different ship types.

[0064] It should be noted that the transverse direction refers to the width direction of the bottom plate 1, and the longitudinal direction refers to the length direction of the bottom plate 1; the side of the inlet channel away from the bottom plate 1 is the first side, and the side of the inlet channel facing the bottom plate 1 is the second side.

[0065] It is also worth noting that step S0 above involves determining the location of the inlet flow channel. Taking modeling as an example, for instance... Figure 2As shown, under normal circumstances, the stern profile provided by the overall unit is the inner wall of the bottom plate 1, while the inner wall of the spray pump inlet channel is the side in contact with water and should be smoothly connected to the outer wall of the bottom plate 1. Therefore, it is first necessary to offset the inner wall profile of the bottom plate 1 provided by the overall unit along the normal direction by one plate thickness to obtain the outer wall of the bottom plate 1. The inlet channel is then set on the outer wall of the bottom plate 1. Then, the layout diagram of the spray pump is consulted to determine the number of spray pumps and their lateral and vertical positions, such as... Figure 3 As shown, three spray pumps are arranged laterally. The lateral arrangement distances need to take into account the water competition phenomenon in the inlet channel. Subsequently, the distribution of the water flow streamline entering the inlet channel is observed through CFD simulation. After multiple iterations and overall confirmation, the stern arrangement position of the spray pumps is determined.

[0066] Figure 4 This is a side view of the completed inlet channel design. Other components of the inlet channel are omitted here; only the connections between the various pipe sections are shown. The following are defined: characteristic diameter D of the inlet channel; axial height H of the inlet channel; axial length L of the inlet channel; inclination angle α of the inlet channel; height H0 of the lip 420 (i.e., the distance between the center of the first rounded portion and the axis); length L1 of the horizontal straight pipe section 100; radius R1 of the first side arc bend pipe section 200, and radius R2-D of the second side arc bend pipe section 200; length L2 of the first side inclined straight pipe section 300; length L3 of the second side inclined straight pipe section 300; radius R2 of the arc portion 411; axial length L4 of the spline portion 412; radius R3 of the second rounded portion; radius R4 of the second rounded portion; and axial length L0 of the inlet of the bottom plate 1.

[0067] The values ​​of the parameters mentioned above are existing technologies in this field and will not be described in detail here.

[0068] Figure 5 This is a comparison diagram of the lip height of the three inlet channels of three spray pumps after installation, using this inlet channel design method.

[0069] This inlet flow channel design method also includes:

[0070] S3: In all longitudinal sections of this inlet channel, the height H0 of the lip 420, the radius R3 of the first rounded portion, and the radius R4 of the second rounded portion are all kept constant. That is, this ensures a smooth circumferential transition between the inner side of the inlet channel and the inlet of the bottom plate 1. Figure 6 and Figure 7 The method is shown to produce the lip 420 profile of the inlet channel in various longitudinal sections.

[0071] Furthermore, this inlet flow channel design method also includes:

[0072] S4: Connect the centers of the first rounded portions on all longitudinal sections of the inlet channel using spline curves. Using the spline curves as the trajectory lines, scan the sector surface containing the first rounded portions on the longitudinal sections along the trajectory lines to set the reinforcing structure 421 of the lip 420, such as... Figure 8 As shown, a reinforcing structure is provided around the outside of the first rounded portion, with the same arc shape as the first rounded portion. The reinforcing structure 421 can increase the structural strength at the inlet lip 420.

[0073] Furthermore, this inlet flow channel design method also includes:

[0074] S5: In the inlet channel, the intersection of the inclined straight pipe section 300 on each longitudinal section with the first rounded part is used as the first cutting point. The first cutting line formed by all the first cutting points and the first cutting surface formed by the vertical direction divide the lip 420 into the first body and the first filling body 431.

[0075] The first connecting portion 11 of the grille 10 is made to have the same shape as the first filler 431 so that the first connecting portion 11 can be adapted to the first body. When the grille 10 needs to be installed, the grille 10 and the first body are connected with the first fastener; when the grille 10 does not need to be installed, the first filler 431 and the first body are connected with the first fastener to fill the position of the first connecting portion 11.

[0076] Traditional inlet channel designs use bolts and nuts to install multiple grids (10 bars), which are independent of each other and vary in length. However, after the grids are removed, bolt connection interfaces remain on the inner wall of this type of inlet channel, causing flow separation and cavitation, which affects propulsion efficiency. This new inlet channel design cuts out a first filler 431 from the inlet channel. The inlet channel with the first filler 431 removed leaves an installation interface for the grids 10, specifically on the side of the first body facing the first filler 431. The first connecting part 11 of the grid 10 is fitted to the first body and also acts as the first filler 431, further smoothing the inner wall of the inlet channel and reducing water flow resistance. After the grids 10 are removed, the first filler 431 is reinstalled and secured with fasteners. The first filler 431 fills the installation interface of the grids 10 and prevents perforation by residual fasteners, thus avoiding any impact on the propulsion efficiency of the water jet propulsion device.

[0077] Specifically, the first fastener is drilled as follows: several first threaded holes are drilled in the same horizontal plane along the direction perpendicular to the first cutting surface, and the first threaded holes are drilled in conjunction with the first connecting part 11 of the grid 10.

[0078] Using the same method, another mounting port for the grille 10 installed on the inlet flow channel is set up, specifically as follows:

[0079] S6: In the inlet channel, the intersection of the inclined straight pipe section 300 on each longitudinal section and the arc portion 411 is used as the second cutting point. The second cutting line formed by all the second cutting points and the second cutting surface formed by the vertical direction divide the arc portion 411 into the second body and the second filling body 432.

[0080] The second connecting portion 12 of the grille 10 is made to have the same shape as the second filler 432 so that the second connecting portion 12 can be adapted to the second body. When the grille 10 needs to be installed, the grille 10 and the second body are connected with the second fastener; when the grille 10 does not need to be installed, the second filler 432 and the second body are connected with the second fastener to fill the position of the second connecting portion 12.

[0081] Furthermore, in the same manner, the perforation of the second fastener is processed, and several second threaded holes are drilled in the same horizontal plane along the direction perpendicular to the second cutting surface. The second threaded holes are drilled to match the second connecting part 12 of the grille 10.

[0082] Figures 9 to 17 The method for cutting the installation interface of the grid 10 on the inlet flow channel and the assembly of the inlet flow channel and the grid 10 are shown.

[0083] This embodiment also provides an inlet channel that can accommodate a detachable grille of the same specification.

[0084] Specifically, the multiple inlet channels on the bottom plate 1 are all designed using the aforementioned inlet channel design method. The total length L of each inlet channel on the bottom plate 1 is equal, the characteristic diameter D of each inlet channel is equal, the radius R2 of the arc portion 411 of each inlet channel is equal, and the height H0 of the lip 420 of each inlet channel is equal. Therefore, the installation position and installation space of the grid 10 of the inlet channel are consistent, so that the different shapes of the inlet channels of the transition pipe section 400 can be adapted to the same specification of grid 10, that is, they are suitable for the universal grid 10.

[0085] Furthermore, the lip 420 of the inlet channel includes a detachably connected first body and a first filler 431. The first filler 431 is flush with the inner wall surface of the inlet channel. The first connecting portion 11 of the grille 10 has the same shape as the first filler 431 so that the first body and the first connecting portion 11 are adapted to each other. The arc portion 411 includes a detachable second body and a second filler 432. The second filler 432 is flush with the inner wall surface of the inlet channel. The second connecting portion 12 of the grille 10 has the same shape as the second filler 432 so that the second body and the second connecting portion 12 are adapted to each other. When the grille 10 needs to be installed, both the first filler 431 and the second filler 432 are disassembled. The first connecting part 11 of the grille 10 is connected to the first body, and the second connecting part 12 of the grille 10 is connected to the second body. The first connecting part 11 and the second connecting part 12 can act as the first filler 431 and the second filler 432 to continue to make the inner wall surface of the inlet flow channel smooth and reduce water flow resistance. After the grille 10 is disassembled, the first filler 431 and the second filler 432 are connected to the first body and the second body respectively, that is, the first filler 431 and the second filler 432 are reinstalled to fill the original installation interface of the grille 10 and maintain the smoothness and continuity of the inner wall surface of the inlet flow channel.

[0086] In this embodiment, the grille 10 is connected by a first fastener and a second fastener. Therefore, the first body, the first filler 431 and the first connecting part 11 have corresponding first threaded holes. The first fastener passes through the first threaded hole to connect the first body and the first filler 431, or to connect the first body and the first connecting part 11. The second body, the second filler 432 and the second connecting part 12 have corresponding second threaded holes. The second fastener passes through the second threaded hole to connect the second body and the second filler 432, or to connect the second body and the second connecting part 12.

[0087] The inlet channel ensures that after the grille 10 is disassembled, there are no residual first threaded holes, thus avoiding affecting the propulsion efficiency of the water jet propulsion device.

[0088] This embodiment also provides a ship waterjet propulsion device, wherein the inlet channels of multiple spray pumps of the ship waterjet propulsion device are adapted to a detachable grid of the same specification.

[0089] Specifically, the ship's waterjet propulsion device includes multiple spray pumps, each of which is equipped with the aforementioned inlet channel. The inlet channel is installed on the outer side wall of the bottom plate 1, and each inlet channel can be equipped with a grid 10 of the same specification.

[0090] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An inlet flow channel design method, used to design and install inlet flow channels for each pump of a ship's waterjet propulsion device on the bottom plate (1), wherein multiple inlet flow channels are arranged laterally at intervals and aligned longitudinally on the bottom plate (1), and the total length L and characteristic diameter D of each inlet flow channel are consistent, characterized in that, The inlet flow channel design method includes the following steps: S1: The horizontal straight pipe section (100), the arc bend pipe section (200), and the inclined straight pipe section (300) of the inlet flow channel are arranged in sequence, such that the horizontal straight pipe section (100) and the inclined straight pipe section (300) are tangent to the two ends of the arc bend pipe section (200), the side of the inlet flow channel away from the bottom plate (1) is the first side, and the side of the inlet flow channel facing the bottom plate (1) is the second side; S2: A transition pipe section (400) for the inlet flow channel is provided. An arc portion (411) and a spline portion (412) are provided on the first side, such that one end of the arc portion (411) is tangent to the inclined straight pipe section (300) on the first side, and both ends of the spline portion (412) are tangent to the arc portion (411) and the bottom plate (1) respectively. A first rounded portion and a second rounded portion are provided on the second side to form a lip (420), such that the first rounded portion is tangent to the inclined straight pipe section (300) on the second side, and the second rounded portion is tangent to the bottom plate (1). The radius R2 of the arc portion (411) of each of the inlet channels is kept consistent, and the height H0 of the lip (420) is kept consistent.

2. The inlet flow channel design method according to claim 1, characterized in that, The inlet flow channel design method also includes: S3: In all longitudinal sections of the inlet channel, the height H0 of the lip (420), the radius R3 of the first rounded portion, and the radius R4 of the second rounded portion are all kept constant.

3. The inlet flow channel design method according to claim 2, characterized in that, The inlet flow channel design method also includes: S4: Connect the centers of the first rounded portions on all the longitudinal sections of the inlet channel with spline curves, and use the spline curves as trajectory lines to scan and set the reinforcing structure (421) of the lip (420) along the trajectory lines of the sector surface where the first rounded portions on the longitudinal section are located.

4. The inlet flow channel design method according to claim 3, characterized in that, The inlet flow channel design method also includes: S5: In the inlet channel, the intersection of the inclined straight pipe section (300) on each longitudinal section with the first rounded part is used as the first cutting point. The first cutting line formed by all the first cutting points and the first cutting surface formed by the vertical direction divide the lip (420) into the first body and the first filling body (431). The first connecting part (11) of the grille (10) is made to have the same shape as the first filler (431) so that the first connecting part (11) is adapted to the first body. When the grille (10) needs to be installed, the grille (10) and the first body are connected with the first fastener; when the grille (10) does not need to be installed, the first filler (431) and the first body are connected with the first fastener to fill the position of the first connecting part (11).

5. The inlet flow channel design method according to claim 4, characterized in that, Step S5 also includes: Several first threaded holes are drilled in the same horizontal plane along a direction perpendicular to the first cutting surface. The first threaded holes are drilled in conjunction with the first connecting part (11) of the grid (10).

6. The inlet flow channel design method according to claim 4, characterized in that, The inlet flow channel design method also includes: S6: Using the same cutting method as in step S5, in the inlet channel, the intersection of the inclined straight pipe section (300) on each longitudinal section with the arc portion (411) is used as the second cutting point. The second cutting line formed by all the second cutting points and the second cutting surface formed by the vertical direction divide the arc portion (411) into the second body and the second filling body (432). The second connecting part (12) of the grille (10) is made to have the same shape as the second filler (432) so that the second connecting part (12) is adapted to the second body. When the grille (10) needs to be installed, the grille (10) and the second body are connected with the second fastener; when the grille (10) does not need to be installed, the second filler (432) and the second body are connected with the second fastener to fill the position of the second connecting part (12).

7. The inlet flow channel design method according to claim 6, characterized in that, Step S6 also includes: Several second threaded holes are drilled in the same horizontal plane along a direction perpendicular to the second cutting surface. The second threaded holes are drilled in conjunction with the second connecting part (12) of the grid (10).

8. An inlet flow channel, wherein the inlet flow channel is disposed on the outer side of the bottom plate (1), characterized in that, The inlet channel is designed using the inlet channel design method according to any one of claims 1-7. The total length L of each inlet channel on the bottom plate (1) is equal, the characteristic diameter D of each inlet channel is equal, the radius R2 of the arc portion (411) of each inlet channel is equal, and the height H0 of the lip (420) of each inlet channel is equal.

9. The inlet flow channel according to claim 8, characterized in that, The lip (420) of the inlet channel includes a detachably connected first body and a first filler (431). The first filler (431) is flush with the inner wall of the inlet channel. The first connecting portion (11) of the grille (10) has the same shape as the first filler (431) so that the first body and the first connecting portion (11) are adapted to each other. The arc portion (411) includes a detachable second body and a second filler (432). The second filler (432) is flush with the inner wall of the inlet channel. The second connecting portion (12) of the grille (10) has the same shape as the second filler (432) so that the second body and the second connecting portion (12) are adapted to each other.

10. A ship waterjet propulsion device, comprising multiple jet pumps, characterized in that, Each of the spray pumps is provided with an inlet channel as described in any one of claims 8 and 9, the inlet channel being installed on the outer side wall of the bottom plate (1).

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