JPS5913196Y2 - Ducted propeller with gas chamber with slit-shaped spout - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a duct propeller having an annular duct around a screw propeller.

Conventionally, ducted propellers are often employed in ships and offshore structures as a means of increasing the thrust generated.

However, with a duct propeller, as shown in Figures 1 and 2, for example, the tip of the propeller 3 is very close to the inner surface of the duct 4, so cavitation occurs mainly at the tip of the propeller blade when the propeller 3 operates. It collapses close to the inner surface of the duct, resulting in cavitation erosion on the inner surface of the duct.

In order to prevent this cavitation erosion that occurs on the inner surface of the duct, it is known that it is best to blow out gas such as air or engine exhaust gas along the inner surface of the duct from the upstream side of the propeller in the vicinity where cavitation collapses. There is.

The location where cavitation collapses is often limited to a circumferential area centered directly above the propeller, and the front and rear locations are also concentrated at the tip of the propeller blade and slightly behind it.

Therefore, it is possible to prevent the occurrence of erosion due to the collapse of cavitation on the inside of the duct by providing several spouts on the inside of the duct in this range and installing a conduit from inside the ship to blow out gas such as air. can.

1 and 2 show a first example of a conventional duct propeller, which includes vertical conduits 17a, 17b provided on both sides of the upper duct support 5, and circumferential conduits 16 provided on the outer surface of the duct. a, 16b, and jet ports 14a, 14b, 14C passing through the duct 4 from the circumferential conduit.

Outlet conduits 15 a, 15 b, 15 leading to 14 d
Gas such as air is sent from inside the ship through C and 15d, and ejected from the spout ports 14a, 14b and 14C and 14d.

3 and 4 show a second example of a conventional duct propeller, in which a vertical conduit 17 is provided penetrating the inside of the upper duct support 5, and circumferential conduits 16a, 16b and a jet nozzle. Conduit 15a, 15b, 15C, 15
d is also provided inside the duct 4.

Furthermore, FIGS. 5 and 6 show a third example of the conventional duct 1 to propeller, in which the vertical conduit 17 is passed through the upper duct 1 to the support 5 and the inside of the duct 1-4, and guided to the inner surface of the duct. A circumferential conduit 16 is disposed on the inner surface and has spout ports 14a, 14b, 14C, respectively.

14d is provided.

In addition, the above 1. 2. In all three cases, the number of spouts was 4.
The case of 1 is shown.

In all of the above-mentioned conventional technologies, in order to prevent cavitation erosion occurring on the inner surface of the duct 1, a plurality of jetting ports are arranged on the upstream side of the propeller near where cavitation collapses, and the air or engine is discharged from the jetting ports. It is characterized by emitting gas such as exhaust gas.

Cavitation collapses mainly in a limited range in the circumferential direction, centered directly above the propeller.
The number of ejection ports is not so large, and in conventional examples, there are often about 3 to 5 ejection ports.

Is the effect of preventing cavitation erosion by jetting gas such as air into the duct 1 from the inside surface improved by increasing the number of jet ports and covering the inside surface of the duct as uniformly as possible? Providing nozzles not only increases manufacturing costs, but also causes a large increase in resistance due to the large number of nozzles protruding into the inner surface of the duct.
The effect of using a ducted propeller will be lost.

Furthermore, in conventional duct propellers, the gas ejection system is entirely provided by piping, which has the disadvantage of a complicated structure.

The present invention attempts to solve the above-mentioned problems with conventional duct propellers by providing a gas chamber within the wall structure of the duct to simplify piping, and by forming the gas outlet in the form of a slit. The purpose of the present invention is to provide a duct propeller that improves the cavitation erosion prevention effect.

Therefore, the duct propeller of the present invention has an annular duct I/
A gas chamber is provided at the front end of the upper duct support and communicates with a gas supply pipe whose outside is streamlined together with the upper duct support. In order to blow out the gas from the gas chamber, the inner plate of the duct) on the upstream side of the screw propeller is provided with a 60° angle in the direction of rotation of the propeller from just above the propeller. It is characterized by a slit-shaped spout opening opening rearward over a range of 30 degrees in the opposite direction to the rotation.

Hereinafter, with reference to the drawings, an embodiment of the present invention will be described.
To explain a duct propeller equipped with a gas chamber with a shaped jet port, Fig. 7 is a side view of the propeller, and Fig. 8 is a side view of the duct propeller.
A cross-sectional view along the line Ill-Vllll, FIG. 9 is I in FIG.
10 is a sectional view taken along line X-IX in FIG. 8, and FIG. 11 is a sectional view taken along line XIM in FIG. 9, showing the screw propeller under the stern water surface. An annular duct 1-4 is provided around the duct 3, which is formed from the duct inner surface plate 4C and the duct I/outer surface plate 4d.

A vertical conduit 17 as a gas supply pipe passing through the upper duct support 5 is provided in front of the front bone plate 5a of the support 5, and is configured in a streamlined shape together with the support 5 having fairing plates 5i and 5j. has been done.

Also, between the duct inner surface plate 4C and the duct outer surface plate 4d, there is a gas chamber 2 into which air or gas such as engine exhaust gas is guided.
5 is provided, and the lower end of the vertical conduit 17 passes through the duct outer surface plate 4d to reach the inside of the duct 4, and communicates with the gas chamber 25 via a communication port 26.

The gas chamber 25 is formed to be separated from other parts by the intermediate rib plates 4h and 4i of the duct, the gas chamber top plate 4j, and the gas chamber duct inner surface plate 4k, and is arranged over a range described below along the circumferential direction of the duct. has been done.

At the rear end of the gas chamber 25, that is, at the downstream end of the inner surface plate 4 of the gas chamber duct, a slit-shaped spout 24 opening toward the rear is provided in the circumferential direction range in which the gas chamber 25 is formed. A slight gap (step) is formed between the duct inner plates 4C, 4 over this range.

The duct inner surface plate 4C in the portion without the gas chamber is formed into a continuous streamlined shape as shown in FIG.

The dimensions of the nozzle 24 may be simply made constant in the circumferential direction, but considering that gas is more likely to be spewed out from the nozzle 24 in the vicinity of the communication port 26, the amount of gas jetted out per unit time is set. In some cases, the dimensions of the slit-shaped ejection openings 24 in the rib 1 may be changed so that the gas film is constant in the circumferential direction, or the gas film is thicker in areas where cavitation erosion occurs intensively.

The circumferential range in which the gas chamber 25 and the jet nozzle 24 are installed is 6 in the direction of rotation of the propeller, centered directly above the propeller 3.
0°, and about 30° in the opposite direction to the propeller rotation.

The vertical conduit 17 is led to a compressor or high-pressure tank as a gas supply source (not shown) inside the ship, and gases such as air or engine exhaust gas are passed through the vertical conduit 17, the communication port 26, and the gas chamber 25. It can be ejected from the ejection port 24.

Blind plates are provided at both ends of the gas chamber 25 in the circumferential direction to prevent the gas from being sent to areas other than where it is needed.

In the present invention, the vertical conduit 17 as a gas supply pipe is provided at the front end of the upper duct support 5 so that the outside thereof is streamlined together with the support 5.
There is no increase in hull resistance, and maintenance and repair of the conduit 17 is easy.

Further, even if the conduit 17 is damaged, there is an advantage that there is no risk of water intrusion inside the support body 5 due to backflow of seawater.

In Figures 7 to 11, numeral 1 is the hull, 2 is the rudder, 3a is the propeller blade cross section, 4a is the front bone plate, 4b is the rear bone plate, 4
e is the longitudinal bone plate, 4f, 4g are the intermediate bone plates, 5b is the posterior bone plate,
5C and 5d are side plates, 5e is a vertical bone plate, 5f and 5g are intermediate bone plates, 5h is a horizontal bone plate, 6 is a propeller shaft, 7 is a propeller cap, 8 is a stern boss, 9a is an upper stern frame,
9b is a lower stern frame, 10 is an upper rudder support, 11
12 is a support for the lower duct 1, and 13 is a rudder handle.

When the propeller 3 is in operation, gas such as air supplied from a gas supply source in the ship via the vertical conduit 17, the connection D26 and the gas chamber 25 is ejected from the sleeve I-shaped ejection port 24, thereby mainly propeller blades. Cavitation generated at the tip can be prevented from collapsing close to the inner surface of the duct 1-4.

In this way, the occurrence of cavitation erosion on the inner surface of the duct 4 is prevented, but in the present invention, the slit-shaped jet port 24 that opens toward the rear is formed continuously over the above-mentioned range along the circumferential direction. By forming a continuous air film in an appropriate range along the inner surface of the duct 1-4, it is possible to more effectively prevent cavitation erosion from occurring on the inner surface of the duct 4. Since the shaped jet nozzle 24 is a continuous opening, its size can be made small, so the gap between the duct inner plates 4c, 4 can be extremely small. Compared to ducted propellers, the resistance can be significantly reduced.

Further, according to the duct I propeller of the present invention, the gas chamber 25 is defined between the inner surface plate 4C and the outer surface plate 4d of the duct 4, so the piping structure is simpler than in the case of a conventional pipe system only. It also has the advantage of being significantly simplified.

[Brief explanation of drawings]

Figures 1 and 2 show an example of a conventional Duc I propeller, with Figure 1 being a side view and Figure 2 being II-I of Figure 1.
It is a cross-sectional view taken along arrow I, and Figures 3 and 4 show other examples of conventional ducted propellers. Figure 3 is a side view thereof, and Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. 5 and 6 show still other examples of conventional duct propellers.
The figure is a side view, FIG. 6 is a sectional view taken along the vI-■■ arrow in FIG. 5, and FIGS. 7 is a side view thereof, FIG. 8 is a sectional view taken along the line Vllll-Vllll in FIG. 7, FIG. 9 is a sectional view taken along the line IXIX in FIG. 8, and FIG. The figure is a sectional view taken along line XX in FIG. 8, and FIG. 11 is a sectional view taken along line XI-II in FIG. 9. 1... Hull, 2... Rudder, 3...
・Propeller, 3a...Propeller blade cross section, 4...
...Duct, 4a...Anterior bone plate, 4b...
...Posterior bone plate, 4C...Duct inner surface plate, 4
d...Dan l-external plate, 4e...Vertical bone plate, 4f, 4g, 4h, 4i...
Intermediate bone plate, 4j... Gas chamber top plate, 4k...
... Gas chamber duct inner surface plate, 5 ... Upper duct 1
To support body, 5a...Anterior bone plate, 5b...
・Posterior bone plate, 5C, 5d...Side plate, 5e...
...Vertical bone plate, 5f, 5g...Intermediate bone plate, 5
h...Horizontal bone plate, 5i, 5j...Fairing plate, 6...Propeller shaft, 7...
・Propeller cap, 8...Stern boss, 9a・
...Upper stun frame, 9b...Lower stun frame, 10...Upper rudder support, 11
... lower rudder support, 12 ... lower duct support, 13 ... rudder handle, 24 ... spout, 25 ... Gas chamber, 17... Vertical conduit as a gas supply pipe, 26... Connection port between the conduit and the gas chamber.

Claims (1)

[Scope of utility model registration request] A gas chamber is provided with an annular duct consisting of an inner surface plate and an outer surface plate around a screw propeller, and communicates with a gas supply pipe provided at the front end of an upper duct support and having a streamlined outer side with the upper duct support. is formed between the inner surface plate and the outer surface plate of the duct, separated from other parts, and is a portion of the inner surface plate of the duct on the upstream side of the screw propeller in order to blow out gas from the same gas chamber. 60 degrees in the direction of rotation of the propeller from directly above the propeller.
A ducted propeller equipped with a gas chamber with a slit-like ejection port, characterized in that a slit-like ejection port is formed rearward over a range of 30° in the opposite direction to the rotation.