JPH07196087A - Injection energy amplifying device in water injection propulsion unit - Google Patents

Abstract

PURPOSE:To obtain remarkable large propulsion force without increasing required power when propulsion force is obtained by injecting water by using an impeller. CONSTITUTION:An acceleration pipe part 30 wherein the flow sectional area is throttled to the downstream side from a duct main body is provided on the rear part of an impeller 10 for accelerating water flow taken into the duct main body 20, and an injection nozzle 40 wherein the flow sectional area is enlarged to maintain the flow speed of the acceleration water flow is continuously provided in this order. A suction port 53 for introducing water flow into the injection nozzle by negative pressure suction force generated by acceleration on the acceleration pipe part and an introducing port 51 for introducing water flow thereto are provided outside the acceleration pipe part 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention accelerates a water flow taken from the front of a duct by an impeller rotating in the duct,
The present invention relates to a device that amplifies injection energy in a water injection propulsion device that obtains a propulsive force by injecting from an injection port at the rear of a duct.

[0002]

2. Description of the Related Art So-called screws (impellers) are known and common as propulsion devices for ships. However, since the propulsion efficiency is low, a ducted fan type propulsion device that rotates a screw in a tubular member has been developed and put into practical use.
However, the inventor of the main body doubted the ability of the conventional thruster, and as a result of repeated studies to further improve the propulsion efficiency, it was found that the use of negative pressure can generate more powerful energy. .

[0003]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned findings, and its object is to provide a new power source for injecting water by using a screw (impeller) to obtain propulsive force. Is needed to provide more propulsive energy than conventional screws.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a water jet propulsion device in which the water flow accelerated by the impeller is further accelerated to the rear of the duct main body surrounding the impeller. An injection nozzle in which an accelerating pipe section whose flow cross-sectional area is narrowed toward the downstream side is installed, the flow cross-sectional area is enlarged in order to promote the acceleration of the water flow by the accelerating pipe section, and the rear end portion of which serves as an injection port. Is continuously installed downstream of the accelerating pipe section, and an intake port for introducing a water flow into the injection nozzle by the negative pressure suction force generated by the acceleration in the accelerating pipe section is provided between the accelerating pipe section and the injection nozzle. An inlet for a water stream formed and guided to the suction port is provided outside the acceleration pipe section.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an injection energy amplifying apparatus for a water injection propulsion device according to the present invention will be described with reference to FIG. The water jet propulsion device equipped with this device is used as a propulsion device for a ship V as shown in FIG. Impeller 10
Is attached to the rotary shaft 12 and is provided for accelerating the water flow in the bottom of the ship or inside the hull.

The duct body 20 has the largest flow cross-sectional area,
It is formed in a substantially cylindrical shape surrounding the impeller 10,
It has a form according to a certain technical condition that improves the propulsion efficiency of the impeller 10. Also the duct body 2
0 has a converging wall 21 whose flow cross-sectional area is gradually narrowed on the upstream side of the impeller, and a surrounding wall 22 surrounding the impeller following the converging wall 21. 13 is a bearing that receives the rotary shaft 12 behind the impeller,
Reference numeral 14 indicates the stay.

At the rear of the duct body 20, there is provided an accelerating pipe section 30 extending downstream from the duct body. The acceleration tube section 30 is
The water flow accelerated by the impeller 10 is further accelerated, and a tapered pipe portion 31 whose flow cross-sectional area gradually decreases toward the downstream, and a parallel throat pipe portion 32 which maintains the minimum cross-sectional area and extends downstream. Consists of. The taper degree of the taper pipe portion 31 is obviously larger than that of the converging wall 21, and the throat pipe portion 32 of the accelerating portion 30 has a minimum flow cross-sectional area for accelerating the water flow as fast as possible.

An injection nozzle 40 is continuously installed downstream of the accelerating pipe section 30 with a transition section 34 having a gradually increasing flow cross-sectional area interposed. The transition portion 34 is provided based on the finding that it is effective to increase the flow cross-sectional area in order to maintain the acceleration of the water flow by the acceleration pipe portion 30, and the transition portion 34 does not have to have an inverse tapered shape as shown in the drawing. May be.

The injection nozzle 40 discharges the water flow accelerated by the accelerating pipe portion 30 into the water from the injection port 41 at the rear end to obtain high propulsion efficiency, and has a flow cross-sectional area close to that of the duct body 10. . The transition portion 34 at the front end of the injection nozzle 40
A negative pressure is formed in the vicinity because the flow velocity is high and the flow cross-sectional area is increasing. This negative pressure causes the injection nozzle 40
By appropriately sucking the water flow therein, the amount of water discharged from the jet port 41 can be increased, and the propulsion efficiency can be improved.

A plurality of suction ports 53 for introducing the water flow into the injection nozzle 40 are opened in the transition portion 34, and the water flow sucked therein can be supplied from two paths.

The first is a method for supplying a water flow from the upstream inside the duct body 20, as shown in FIG. In this case, a plurality of water flow inlets 51 are opened on the outer circumference and upstream of the acceleration pipe section 30. The water flow flowing in the duct has the highest speed in the center, and the flow whose height is lowered in contact with the wall surface is sucked from the inlet 51. To supply this water flow, the outer side of the acceleration pipe portion 30 is covered and surrounded by the pipe portion 33 to form a bypass passage 52. In the case of FIG. 1, the duct body 20, the cover tube portion 33, and the injection nozzle 40 are integrated,
The components of the accelerating tube section 30 are mounted in the cover tube section 33 to form the amplifying apparatus A according to the present invention.

The second method of supplying the water flow to the suction port 53 is to attach the water flow from the outside of the duct (FIG. 2). Therefore, the space between the duct body 20 and the acceleration pipe section 30 is completely closed, An introduction port 51 is opened near the boundary between the duct body 20 and the covering pipe portion 33. In the case of this example, the bypass passage 52 is not always necessary, and the inlet 51 may be provided directly to the inlet 53. In FIG. 2, other configurations may be the same as in the example of FIG. 1, so reference numerals are used and description thereof is omitted.

When the engine operates and the impeller 10 rotates in the apparatus of the present invention thus constructed, the water flow flowing in the apparatus is accelerated by the impeller 10 and then immediately accelerated again in the accelerating pipe section 30, so that the injection nozzle 40 Due to the negative pressure generated near the transition portion at the front end, the water flow is forcibly sucked into the injection nozzle 40 from the suction port 53 by the negative pressure.

By this suction, the water flow in the duct body is forcibly sucked from the suction port 53 and flows into the injection nozzle 40,
An injection port 41 that merges with the main water flow that has passed through the acceleration pipe section 30.
Is injected into the water from. At the same time, in the example of FIG. 1, the water flow in the duct body 20 is carried away from the vicinity of the impeller, so that the negative pressure applied to the impeller 10 and the engine that drives it can be significantly reduced. Further, it is possible to delay the occurrence of cavitation due to the impeller.

[0015]

Since the present invention is configured as described above, the water flow is forcibly sucked into the injection nozzle from the suction port by the negative pressure suction force accelerated by the impeller and further generated by the acceleration in the acceleration pipe section. As a result, the amount of injected water can be increased by almost the amount of forced suction water, so that the propulsion output can be significantly increased while maintaining the required power. Further, the present invention has the following features. 1) The engine load is light at the same speed. 2) At the same speed, the economy of the engine increases. 3) The rise to obtain a constant thrust is quick. 4) Since there are no moving parts, productivity is good and there is no risk of breakdown.

[Brief description of drawings]

FIG. 1A is a vertical sectional view showing a first embodiment of an injection energy amplifying device according to the present invention. (B) The rear view of the above.

FIG. 2 (a) is a longitudinal sectional view showing a second embodiment of the device according to the present invention. (B) The rear view of the above.

FIG. 3 (a) is a schematic side view of a ship equipped with the device according to the present invention. (B) The rear view of the above.

Claims (6)

[Claims] 1. A water injection propulsion device for accelerating a water flow taken from the front part of a duct by an impeller rotating in the duct and injecting it from an injection port at the rear part of the duct to obtain propulsion force,
In order to further accelerate the water flow accelerated by the impeller, at the rear part of the duct body surrounding the impeller, an acceleration pipe part whose flow cross-sectional area is narrowed toward the downstream side of the duct body is installed, and the acceleration pipe part The flow cross-sectional area is enlarged to maintain the acceleration of the water flow, and the injection nozzle whose rear end is the injection port is continuously installed downstream of the acceleration pipe section, and the negative A structure in which a suction port for introducing a water flow into the injection nozzle by a pressure suction force is formed between the acceleration pipe section and the injection nozzle, and a water flow introduction port leading to the suction port is provided outside the acceleration pipe section. For amplifying injection energy in a water injection propulsion device having a valve. 2. The duct main body has the largest flow cross-sectional area among the duct main body, the accelerating pipe portion and the injection nozzle, and the minimum flow cross-sectional area portion of the accelerating portion is the smallest. The injection energy amplifying device in the water injection propulsion device according to claim 1, wherein the amplification device is set so as to take an intermediate value. 3. The accelerating pipe section is composed of a taper pipe section whose flow cross-sectional area gradually decreases toward the downstream side and a throat pipe section which extends downstream with the minimum cross-sectional area thereof. The injection energy amplifying device for a water injection propulsion device according to claim 1, wherein the injection energy is continuous with the injection nozzle via a gradually enlarged transition portion. 4. A cover pipe portion surrounding the outside of the acceleration pipe portion is provided, and an outer surface of the acceleration pipe portion and an inner surface of the cover pipe portion form a bypass passage, and an upstream end of the bypass passage is an inlet port. The apparatus for amplifying injection energy in a water injection propulsion device according to claim 1, wherein the downstream end thereof is an intake port. 5. The injection energy amplifying device for a water injection propulsion device according to claim 4, wherein the intake port is open on the upstream side of the bypass passage so as to communicate with the water flow inside and outside the duct body. 6. The injection energy amplifying device for a water injection propulsion device according to claim 4, wherein the suction port is provided on the upstream side of the bypass passage so as to communicate with a water flow flowing from the outside of the duct body.