JPH0737894U - Water jet propulsion ship intake - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an intake port of a high-performance water jet propulsion ship that enhances strength and prevents the occurrence of cavitation. [Structure] In a water intake propulsion ship, at a water intake 2 having a grid 1 at a front end opening of a suction pipeline 4 and a guide vane 8 extending rearward along the pipeline inside the pipeline 4, the guide vane is provided. The front end of 8 is integrally fixed to the rear end of the grid 1, and at least a pair of grids 1 near the wall surface of the front end opening among the plurality of grids 1 have a front-spreading asymmetrical type in which the front ends spread to each other. It should have an airfoil cross section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a water intake of a water jet propulsion ship of a ship.

[0002]

[Prior art]

 Conventionally, in a water jet propulsion ship, as shown in FIGS. 5 to 6, the guide vane 8 of the intake port 2 is attached to the wall surface of the intake port 2 separately from the grid 1. In addition, the cross-sectional shape of each conventional grid 1 is a left-right symmetrical type, as shown in FIG. 7, a rectangular shape, or a rectangular shape with rounded front and rear end corners as shown in FIG. 8, or an arc shape. The cross-sectional shape of the grid is generally the same (even at different installation locations).

[0003]

[Problems to be solved by the device]

 It is advantageous for the guide vane 8 to be as close to the grid 1 as possible in terms of the strength of the water intake port 2, and it is possible to reduce the thickness of the outer plate of the water intake port 2. However, in that case, as shown in FIG. 7, the leading edge of the guide vane 8 is located in the wake portion near the grid where the flow direction changes greatly, and cavitation 9 occurs from the leading edge. Further, as shown in FIG. 9, the flow in front of the water intake 2 for taking in water to the water jet pump 3 while the ship is accelerating is from the outside toward the inside of the water intake. Therefore, the angle of attack is positive with respect to the intake port 2 and the grid 1, and the inner surface of the intake port and the surface of the grid have a low pressure, causing cavitation 11.

The present invention has been proposed in view of such circumstances, and an object thereof is to provide a water intake port of a high-performance water jet propulsion ship that enhances strength and prevents the occurrence of cavitation.

[0005]

[Means for Solving the Problems]

 To this end, the invention of claim 1 has a grid at the front end opening of the suction pipeline of the water jet propulsion ship and an intake having a guide vane inside the pipeline that extends rearward along the pipeline. The front end of the guide vane is integrally fixed to the rear end of the grid.

According to a second aspect of the present invention, there is provided a water jet propulsion vessel, wherein the intake pipe has a grid at a front end opening of the suction pipe and a guide vane extending rearward along the pipe in the intake pipe. Among the plurality of grids, at least one pair of grids near the wall surface of the front end opening has a front-spreading asymmetric airfoil cross section in which the front ends spread out from each other.

The invention of claim 3 is characterized in that the grid of claim 2 is provided in claim 1.

[0008]

[Action]

 According to this structure, since the leading edge of the guide vane changes its flow direction greatly, the pressure is likely to be low and cavitation is likely to occur. Since the portion coincides with the front edge of the grid, the surface of the guide vane 8 has a smooth flow, and the pressure does not become low enough to cause cavitation. Also, the flow between the intake and the grid is slowed by the effect of the grid. As a result, the pressure on the inner surface of the intake is not low enough to cause cavitation. Furthermore, since the grid also follows the flow, cavitation does not occur from the grid.

[0009]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. FIG. 1A is a perspective view of the grid and guide vanes, and FIG. 2 shows a second embodiment of the present invention. FIG. 2A is a vertical sectional view of the grid, FIG. 2B is a front view of FIG. 3 is an enlarged view showing the part III in FIG. 2, and FIG. 4 is a comparison diagram comparing the negative pressure distributions of the intake according to the present invention and the conventional intake.

First, in the first embodiment shown in FIG. 1, the same reference numerals as those in FIG. 6 denote the same members as in the same drawing, and the grid 1 is composed of two blades vertically and three blades horizontally. It The guide vane 8 is integrated with the central blade of the three horizontal blades of the grid. The grid 1 acts to prevent foreign matter such as driftwood from entering the pump 3 (FIG. 5), and the guide vanes 8 have the action of rectifying the flow of water in the suction pipe line 4 and reinforcing the strength of the intake port 2. .

According to the first embodiment described above, by integrating the front end of the guide vane 8 with the grid 1, cavitation on the guide vane 8 is less likely to occur. Moreover, since the strength of the intake port 2 is also increased, it is possible to reduce the plate thickness of the wall surface of the intake port 2 and reduce the weight of the hull 5.

Next, in the second embodiment shown in FIG. 2, the cross-sectional shape of the left-right pair and / or the upper-bottom pair of grids that are closest to the wall surface of the intake port 2 has an asymmetric airfoil shape 1 respectively. a. The cross-sectional shapes of the other grids are left-right symmetric cross-sections 1b.

According to such a grid structure, the water flow 10 flows between the intake port 2 and the guide vane 8 as shown by the arrow in FIG. 3, so the pressure of the water flow is shown by the solid line in FIG. Since there is no negative pressure, cavitation does not occur due to the inner surface of the intake and the grid 1a. Therefore, it is possible to prevent erosion from occurring in the water intake 2 and the grid 1, which is a problem due to the occurrence of cavitation. Further, it also solves the problem that the suction capacity of the pump 3 is lowered due to the cavitation generated in the intake port.

[0014]

[Effect of device]

 In short, according to the invention of claim 1, in the water intake having the grid at the front end opening of the suction pipeline of the water jet propulsion ship and the guide vane extending rearward along the pipeline inside the pipeline. By integrally fixing the front end of the guide vane to the rear end of the grid, a high-performance water jet propulsion ship intake port that increases strength and prevents cavitation can be obtained. Since cavitation on the id vanes is less likely to occur and the strength of the water intake is stronger, the wall thickness can be made thinner and the hull can be made lighter. Therefore, the present invention is extremely useful industrially. .

According to the second aspect of the present invention, the water intake port of the water jet propulsion ship has a grid at the front end opening and a water intake port having a guide vane inside the pipe line and extending rearward along the pipe line. In at least one of the plurality of grids, at least a pair of grids near the wall surface of the front end opening has a front-spreading asymmetric airfoil cross-section with the front ends expanding from each other. Since this can prevent the occurrence of erosion of the intake and grid based on this, this proposal is extremely useful in industry.

According to the third aspect of the present invention, by providing the grid of the second aspect in the first aspect, it is possible to reduce the weight of the hull and enhance the durability of the intake port and the grid. The present invention is extremely useful in industry.

[Brief description of drawings]

FIG. 1 shows a water intake of a first embodiment of the present invention. FIG. 1A is a perspective view of the grid and guide vanes, and FIG. 1B is a vertical sectional view of FIG. 1A. is there.

FIG. 2 shows a second embodiment of the present invention and is shown in FIG.
Is a vertical cross-sectional view of the grid, FIG. 7B is a front view of FIG. 7A, and FIG. 7C is a partially enlarged view of FIG.

FIG. 3 is an enlarged view showing a part III in FIG.

FIG. 4 is a comparison diagram comparing negative pressure distributions of an intake according to the present invention and a conventional intake.

FIG. 5 is a side view of a hull showing a watercraft equipped with a conventional water jet.

6 is a perspective view showing the water intake port of FIG. 5. FIG.

7 is a vertical cross-sectional view of an intake port showing cavitation of the guide vane in FIG.

FIG. 8 is a view showing a cross section of a conventional grid.

FIG. 9 is a cavitation on the inner surface of the intake port and the grid of FIG.
FIG.

[Explanation of symbols]

 1 grid 1a asymmetric cross-section grid 1b symmetrical cross-section grid 2 intake 3 pump 4 suction line 5 hull 6 strut 7 pod 8 guide vane 9 cavitation 9a grid bottom 9b grid top 10 water flow between intake and grid 11 cavitation

Claims (3)

[Scope of utility model registration request] 1. A water intake having a grid at a front end opening of a suction pipe line of a water jet propulsion ship and a guide vane extending rearward along the pipe line inside the pipe line, the front end of the guide vane being provided. An intake structure for a water jet propulsion ship, which is integrally fixed to the rear end of the grid. 2. An intake port having a grid at a front end opening of a suction pipeline of a water jet propulsion ship and having a guide vane extending rearward along the pipeline inside the pipeline, among a plurality of grids. An intake structure for a water jet propulsion ship, characterized in that at least a pair of grids near the wall surface of the front end opening have a front-spreading asymmetrical airfoil cross section in which the front ends spread out from each other. 3. The water intake structure for a water jet propulsion ship according to claim 1, wherein the grid according to claim 2 is provided.