JP3263555B2 - Marine propeller device with stator fins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marine propeller device and, more particularly, to a marine propeller device with a stator fin that utilizes a rotating flow generated behind a propeller to improve propeller efficiency.

[0002]

2. Description of the Related Art FIG. 6 shows a stern of a ship equipped with a normal propeller. Propeller 4 rotates through a propeller shaft 3 by a main unit 2, by accelerating the surrounding fluid backwards, it generates a thrust T _p as a reaction. In FIG. 1, reference numeral 1 denotes a hull, 4a denotes a propeller blade, 4b denotes a propeller boss, 5 denotes a rudder, and 6 denotes a wake behind the propeller.

[0003]

Propeller 4 [SUMMARY OF THE INVENTION] is by accelerating the surrounding fluid in the rear, not only generates a thrust T _P, the rotational flow of the rotary and the same direction of the propeller in the propeller slipstream 6 Induce. This rotational flow does not contribute to the thrust T _P , and the propulsion efficiency of the propeller 4 is reduced by the amount of the rotational energy.

According to the present invention, a stator fin for improving the propulsion efficiency of a propeller by utilizing the rotational flow is provided, and a moment generated when the stator fin is operated is reduced as much as possible. An object of the present invention is to provide a marine propeller device with a stator fin which is simple and low in cost.

[0005]

In order to achieve the above-mentioned object, a marine propeller device with a stator fin according to the present invention is provided.
In a marine propeller device, the marine propeller device includes a stator fin including a plurality of fins disposed behind the propeller and fixed to and supported by a hull so as to project radially from a center axis of the propeller shaft. The fin torsion angle and fin cross-sectional shape are set at the root fin portion within a range corresponding to 70 to 100% of the radius so as to generate a rotational flow in the direction opposite to the propeller rotation direction. Is characterized in that the fin torsion angle and the fin cross-sectional shape are set so as to generate a rotational flow in the same direction as the propeller rotation direction in the tip fin portion connected to the fin.

[0006]

In the above-described marine propeller device with a stator fin according to the present invention, the rotational flow generated from the propeller is straightened by the root fin portion serving as a central portion excluding the tip fin portion of the stator fin disposed behind the propeller. The effect of turning into a flow is provided, which most effectively converts the energy of the rotating flow into thrust and increases the propulsion of the hull. At the same time, a large moment in the same direction as the rotation direction of the propeller is generated due to the action of the root fin portion, but each tip fin portion of the stator fin generates a rotational flow in the same direction as the rotation direction of the propeller. ,
Since a moment in the direction opposite to the direction of rotation of the propeller is generated, the moment generated by the root-side fin portion is canceled.

The tip fin portion of the stator fin simultaneously generates a resistance component to cancel the thrust generated at the root fin portion as the center portion of the stator fin, but the resistance component is quantitatively reduced. Since it is small, the action of increasing the thrust is performed on the whole stator fin.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a marine propeller device with a stator fin as one embodiment of the present invention, FIG. 2 is a rear view of FIG. 3 is an explanatory diagram showing a cross section of a root fin portion of a stator fin and a velocity vector of water flow, FIG. 4 is an explanatory diagram showing a cross section of a tip fin portion of the stator fin and a velocity vector of water flow, and FIG. 2 is a graph showing the propulsion efficiency of the marine propeller device with a stator fin in comparison with the case without a stator fin.

In FIG. 1, a propeller 4 has a propeller shaft 3.
, And is driven by the main engine 2 through the main engine 2. In this embodiment, a right-rotating propeller is shown. Propeller 4 and rudder 5
A stator fin composed of a plurality of fins 8 projecting radially from the center line of the propeller shaft is provided between the fins 8, and each fin 8 is attached to a stator fin boss 9. In this embodiment, the stator fin boss 9 is supported by the hull 1 via the rudder horn 7 that supports the rudder 5.
Other means may be used for support.

Each fin 8 of the stator fin has a root fin portion (a propeller radius of 70 mm from the propeller axis center line).
The fin torsion angle and the fin cross-sectional shape are set so as to generate a rotational flow in the direction opposite to the rotational direction of the propeller 4) in the fin portion 8a within a range corresponding to 100%. That is, the root-side fin portion 8a has its cross-sectional shape and pitch angle γ set as shown in FIG. 3 so as to have an appropriate angle of attack α with respect to the wake from the propeller blade 4a. .

On the other hand, the tip-side fin portion 8b connected to the root-side fin portion 8a has a sectional shape and a pitch angle γ such that a rotational flow in the same direction as the propeller rotation direction is generated as shown in FIG. It is set so as to have an appropriate angle of attack α for a flow without a rotational flow after the propeller.

Next, the thrust generating mechanism of the marine propeller device with stator fins of this embodiment will be described.
Although shows the velocity vectors of the cross-sectional shape and flow of the base side fin portions 8a of stator fins, synthesis rate W of the circumferential flow V _t by rotating the axial flow V _x accelerated by the propeller wings 4a is , Root side fin part 8
When a α angle of attack flows into a, lift L _a and drag D _a
Occurs. Axial component of the resultant force between the lift L _a and drag D _a is thrust generated T _s of the root-side fin portions 8a.
Further, the circumferential direction component is a rotating force F, is this rotational moment M _a root side fin portions 8a obtained by multiplying the distance l _a from the center of the stator fins boss 9 expressed by [Expression 1] .

[Number 1] M _a = F × l _a

FIG. 4 shows the sectional shape of the tip fin portion 8b of the stator fin and the velocity vector of the water flow.
Since the distal end fin portion rotating flow by the propeller 4, 8b is not or less, the circumferential velocity V _t may be considered to be almost zero.

[0014] Thus, for the axial velocity V _x, setting the pitch angle γ to have α appropriate angle of attack, lift L _b and the drag D _b is generated, the stator fins boss 9 to lift L _b When multiplied by the distance l _b from the center of rotation moment M _b acting on the distal end side fin portion 8b is expressed by [equation 2] expression.

[Number 2] Thus _{M b = L b × l b} , the rotational moment M acting on each fin 8 is represented by [Expression 3] expression.

## EQU3 ## M = M _a −M _b

If M is large, it is necessary to make the supporting structure of the stator fin boss 9 and the rudder horn 7 for supporting the fin boss strong, which increases the cost. Therefore, M is made small so that M becomes acceptably small. _{Since b} may be set and l _b is larger than l _a , the tip fin portion 8b of the stator fin may be shorter than the root fin portion 8a.

On the other hand, the resultant thrust T of the propeller device with the stator fin is expressed by the following equation (4).

The [number 4] _{T = T p + T s -D} b. Here, T _p is the thrust of the propeller.

The base side fin portion 8a of the stator fins is greater than the tip-side fin portion 8b, and since the inflow velocity is large, the T _s> D _b. Therefore, since the T> T _p, in marine propeller device with stator fins examples will generate a large thrust than conventional propeller device. Further, since the moment acting on each fin 8 of the stator fins can be appropriately reduced, there is an advantage that the structure is simplified and the cost is reduced.

[0018]

As described above, according to the marine propeller device with a stator fin of the present invention, the following effects can be obtained. (1) The propulsion efficiency of the propeller is increased by using the rotational flow downstream of the propeller by the root fin part of the stator fin behind the propeller, while the rotational moment generated at the root fin part is connected to the root fin part The rotational moment generated by the fin portion on the tip side is offset. (2) By canceling the rotational moment in the above item (1),
The effect of simplifying the support structure of the stator fin is obtained, and there is an advantage that the cost is reduced accordingly.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a marine propeller device with a stator fin as one embodiment of the present invention.

FIG. 2 is a rear view taken along the line AA of FIG. 1;

FIG. 3 is an explanatory diagram showing a cross section of a root fin portion of a stator fin of the apparatus of FIG. 1 and a velocity vector of a water flow.

FIG. 4 is an explanatory diagram showing a cross section of a tip fin portion of a stator fin of the apparatus of FIG. 1 and a velocity vector of a water flow.

FIG. 5 is a graph showing the propulsion efficiency of the apparatus of FIG. 1 in comparison with the case without a stator fin.

FIG. 6 is a longitudinal sectional view showing a conventional marine propeller device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hull 2 Main engine 3 Propeller shaft 4 Propeller 4a Propeller blade 5 Rudder 6 Propeller wake 7 Rudder horn 8 Fin 8a Root side fin part 8b Tip side fin part 9 Stator fin boss

Claims (1)

(57) [Claims] 1. A marine propeller apparatus, comprising: a stator fin comprising a plurality of fins disposed behind a propeller and fixedly supported on a hull so as to project radially from a center line of a propeller shaft; In the root fin portion within a range corresponding to 70 to 100% of the propeller radius from the axis center line, the fin torsion angle and the fin cross-sectional shape are set so as to generate a rotational flow in a direction opposite to the propeller rotation direction. A marine propeller with a stator fin, characterized in that a fin torsion angle and a fin cross-sectional shape are set at a tip-side fin portion connected to the root-side fin portion so as to generate a rotational flow in the same direction as the propeller rotation direction. apparatus.