JP3245000B2 - Ship - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ship provided with a ring-shaped nozzle in front of a propeller of the ship to improve the propulsion performance of the ship.

[0002]

2. Description of the Related Art A ring-shaped nozzle provided in front of a propeller of a ship includes a wedge-shaped nozzle 3a and a trapezoidal nozzle (not shown) as shown in FIG.

[0003]

[SUMMARY OF THE INVENTION The nozzle, in particular, the nozzle shown in FIG. 9, a large flow of wake coefficient w flowing near the top of the propeller plane _{(w = (V S -V a} ) / V S) Rectification, the generation of three-dimensional separation vortices generated from the bilge portion of the hull can be suppressed. Then, the hull resistance can be reduced, and the propulsion efficiency η (η = η _h · η _o · η _R ) can be improved. V _S is the ship speed, and V _a is the propeller inflow velocity. Also, η _h is called the hull efficiency, and is expressed by η _h = (1-t) / (1-w).

[0004] Further, η _o is the propeller independent efficiency in a state where it is not affected by the hull. η _R is called the propulsor efficiency ratio and is the ratio of the propeller efficiency to the propeller independent efficiency η _o with the propeller operating in the wake of the stern. Note that t is a thrust reduction rate. In order to exhibit the characteristics of the nozzle, the circulation Γ acting on the nozzle may be increased. To increase the nozzle circulation Γ
As in the case of 0, the angle of attack α of the flow flowing into the nozzle 3a may be increased, and the chord length L of the nozzle 3a may be increased.

However, in recent enlarged vessels, the wake distribution on the propeller surface is distributed as shown in FIG.
The in-plane flow direction in the propeller plane has a direction as shown in FIG. Therefore, the wedge-shaped nozzle 3a as shown in FIG. 9, the nozzle leading edge LE (see FIG. 10), will have a distribution of angle of attack α and velocity V _a as shown in FIG. 13. The horizontal axis in FIG. 13 is the angle in the circumferential direction of the nozzle, and the vertex of the nozzle, in other words, the position at 0 o'clock when the nozzle is viewed as a clock is 0 °, and the direction of the propeller from the bow is the direction of the propeller. To the right, that is, an angle measured clockwise. 180 ° from FIG.
It can be seen that the flow field is symmetric with respect to.

As shown in FIG. 10, the propulsive force F _N acting on the nozzle is a sine component of the angle β of the lift L _N acting on the nozzle, and is represented by F _N = L _N · sin β. On the other hand, the lift L _N is proportional to the circulation Γ of the nozzle, and the circulation Γ is proportional to the angle of attack α and the chord length L of the nozzle.

L _N ∝Γ∝α · V _a ² · L Therefore, the propulsion force F _N acting on the nozzle is F _N ∝α · V _a ² · L · sin β. A frictional resistance _Df acts on the nozzle cross section. The frictional resistance D _f is expressed by D _f αV _a ² · L.

Further, the force F _T acting on the _{nozzles, F T = (C 1 ·} α · sin β-C 2) · V a 2 · L≡A ·
V _a ² · L. Here, C ₁ and C ₂ are proportional constants. Therefore, in order to improve the propulsion efficiency η, the angle of attack α is large and A
Is positive, the chord length L of the nozzle is increased,
It can be seen that the chord length L of the nozzle may be reduced in the portion where the angle of attack α is small and A is negative.

[0009] Figure 14 shows the distribution of forces F _T acting on the wedge-shaped nozzle such as Figure 9. However, when the diameter of the rear end of the nozzle becomes smaller than the diameter of the propeller,
Distribution of angle of attack α and velocity V _a at the nozzle leading edge is shown in Figure 15. Then, the force F _T acting on the nozzle, FIG. 1
It looks like 6. As shown in FIGS. 14 and 16, the nozzle becomes a resistance in the vicinity of 90 ° and 270 ° clockwise from the vertex 0 ° of the nozzle, and the wedge-shaped nozzle or the trapezoidal nozzle shown in FIG. It is impossible to maximize the effect. An object of the present invention is to provide a ship provided with a ring-shaped nozzle that overcomes the above problems.

[0010]

Means for Solving the Problems That is, the present invention provides a professional
A ring-shaped nozzle is provided in front of the propeller.
Joint where the upper leading edge of the leading edge and the lower leading edge of the nozzle join
Is located in the vicinity of a horizontal plane including the propeller shaft axis , the joint portion is more propelled than the tip of the nozzle bottom.
It is characterized by approaching the la.

Further, the nozzle is located in front of the propeller.
Provided, and, together with through upper and lower two support members fixed to the hull, it is desirable to have a direction opposite to the direction of rotation of the twist of the propeller to the support member.

[0012]

[Operation] As described above, the joint at the leading edge of the nozzle
Closer to the propeller than to the tip of the nozzle bottom
Then, the propulsion component of the nozzle does not change much, but the component serving as the resistance is greatly reduced.

[0013] As the component which becomes the resistance of the nozzle decreases, the flow rate flowing into the nozzle also increases. And consequently,
Since the flow having a large wake coefficient w can be concentrated and rectified, the effect of the nozzle is maximized and the propulsion efficiency η
Can be further improved.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a ship, which has a ring-shaped nozzle 3 in front of a propeller 2. This nozzle 3
Has a smaller diameter toward the rear. Also, this nozzle 3
The axis Ca is coaxial with the propeller axis C,
Further, the section including a plane including the propeller shaft axis C has an airfoil shape protruding inward.

The nozzle 3 has a leading edge 4 whose upper leading edge 4
1 and a lower front edge 42, and the upper front edge 41 is closer to the propeller 2 as it goes downward. And the upper front edge 41
The joint 5 where the lower front edge 42 is joined to the propeller 2 is closer to the tip 7 of the nozzle bottom 6. And
The joint 5 is adapted to the inflection point, the inclination angle of the inclined angle theta ₁ and the nozzle lower front edge 42 of the nozzle upper leading edge 41 theta ₂
Has changed. Here, θ ₂ > θ ₁ .

Further, the joint 5 is provided with a propeller shaft center C.
Are located on the horizontal plane. In addition, this nozzle 3
The rear edge 8 is closer to the bow as it goes down.
The nozzle 3 is fixed to the hull 11 via two upper and lower support members 9 and 10. The support members 9 and 10
As shown in FIG. 2, the rear end is made thinner and has a twist in the direction opposite to the rotation direction of the propeller 2. Thus, the rotational flow in the same direction as the rotation of the propeller generated behind the propeller 2 can be reduced.

When the ring-shaped nozzle 3 is used, the force F _T acting on the nozzle has a distribution as shown by a broken line in FIG.
The solid line indicates the distribution of the force F _T acting on the wedge-shaped nozzle. As can be seen from FIG. 7, although the propulsion component of the nozzle does not change much, the component serving as a resistance greatly decreases. As the component that becomes the resistance of the nozzle decreases, the flow rate flowing into the nozzle also increases. As a result, the flow having a large wake coefficient w can be more concentratedly rectified, so that the effect of the nozzle can be maximized and the propulsion efficiency η can be further improved.

FIG. 8 shows a self-propulsion factor (η) related to the propulsion efficiency η.
_R , 1-t, and 1-w) are shown to be improved. From FIG. 8, the present invention shows that 1-t is increased, and the operation of the nozzle is more effectively performed. You can see that it is. In FIG. 8, (a) shows no nozzle,
(B) shows the case of using the wedge-shaped nozzle of FIG. 9, and (c) shows the case of the present invention.

This tendency is caused by the diameter D at the rear end of the nozzle.
Similar effects can be expected not only when _N is smaller than the propeller diameter D _P but also when _N is larger than the propeller diameter D _P. The diameter D _{N at the} rear end of the nozzle is the diameter D of the propeller
About 40 to 110% of _P is desirable. Straight at the rear end of the nozzle
The diameter D _N is less than 40% of the diameter D _P of the propeller, the flow
Speed V _a decreases throughout the circumferential direction, it acts on the nozzle
The propulsive force F _N becomes smaller. Conversely, right at the rear end of the nozzle
The diameter D _N is greater than 110% of the diameter D _P of the propeller, Fig.
Also the flow velocity V _a increases over the entire circumferential direction shown in 13
However, since the elevation angle α becomes smaller as a whole, the propulsion force F _N becomes
Small, high frictional resistance. In FIG.
3 is a rudder.

As shown in FIG. 4, when the Costa valve 14 is attached to the rudder 13, the hull resistance can be further reduced by a synergistic effect with the nozzle 3. The Costa valve 14 includes a head 15 and a body 16, the head 15 is fixed to a rudder horn 17, and the body 16 is
It is fixed to. Further, the rear end face 20 of the cap 19 and the valve head 15 are arranged so that a step does not occur between the cap 19 attached to the propeller boss 18 and the Costa valve 14.
Are near the same diameter, so that the flow can flow smoothly.

Also, as shown in FIG.
2, the degree of twisting of the support members 9a and 10a may be increased. Further, as shown in FIG.
The lower support member 10b may have a straight structure along the propeller shaft axis C by applying a twist to only the lower support member 10b. When the nozzle 3 is viewed from right beside, the joint portion 5 has a propeller shaft center C.
Although it is located on the upper side, the joint portion 5 is located slightly above the propeller axis C, or
The same effect can be obtained even if it is positioned slightly below.

The trailing edge 8 and lower leading edge 42 of the nozzle 3
May be vertical. Further, the chord length of the nozzle at the joint 5 may be minimized in accordance with the flow field.
In FIG. 1, L ₁ is the chord length at the top of the nozzle, L ₂
Is the chord length at the bottom of the nozzle.

[0023]

As described above, the present invention relates to a ship provided with a ring-shaped nozzle in front of the propeller of the ship, wherein the nozzle has an upper front edge and a lower front edge,
The upper front edge is closer to the propeller side downward, and at the junction where the upper front edge and the lower front edge are joined, the inclination angle of the nozzle upper front edge and the inclination angle of the lower front edge are changed. Since the nozzle is positioned near the horizontal plane including the axis of the propeller shaft, the propulsion component of the nozzle is not changed much, but the resistance component is greatly reduced, and the flow rate flowing into the nozzle is also increased. As a result, the flow having a large wake coefficient w can be more concentratedly rectified, so that the effect of the nozzle can be maximized and the propulsion efficiency η can be further improved.

[Brief description of the drawings]

FIG. 1 is a side view of a ship according to the present invention.

FIG. 2 is a sectional view of a main part of the ship according to the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a side view showing another example of the ship according to the present invention.

FIG. 5 is a rear view of a ring showing another example of a support member that supports the nozzle.

FIG. 6 is a rear view of the ring showing an example in which only the upper support member is twisted.

7 is a distribution diagram of the force F _T acting on the nozzle.

FIG. 8 is an explanatory diagram showing a difference between self-propelled elements of the present invention and Conventional Examples 1 and 2.

FIG. 9 is a side view of a conventional ship having a wedge-shaped nozzle.

FIG. 10 is a diagram illustrating the function of a nozzle.

FIG. 11 is a wake distribution diagram in a propeller plane.

FIG. 12 is a vector diagram of an in-plane flow direction in a propeller plane.

FIG. 13 is a distribution diagram of the attack angle α and the flow velocity Va in the nozzle circumferential direction.

14 is a distribution diagram of the force F _T acting on the nozzle.

FIG. 15 shows the angle of attack α when the nozzle diameter is smaller than the propeller diameter.
FIG. 4 is a distribution diagram of the flow velocity Va in the nozzle circumferential direction.

[16] the nozzle diameter is a distribution diagram of the force F _T acting on the nozzle when less than the propeller diameter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ship 2 Propeller 3 Ring-shaped nozzle 4 Nozzle leading edge 5 Joint 6 Nozzle bottom 7 Nozzle bottom tip 41 Upper leading edge 42 Lower leading edge C Propeller axis

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akihiko Fujii 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Co., Ltd. (72) Inventor Hiroki Takahashi 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Incorporated company (56) References JP-A 56-147195 (JP, U) JP-A 3-17996 (JP, U) JP-A 62-52598 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B63H 5/16 B63H 1/20

Claims (2)

(57) [Claims] 1. A ring-shaped nozzle is provided in front of a propeller.
Equipped, and the upper leading edge of the leading edge of the nozzle and the lower leading edge of the nozzle
The joint that joins the edge is a horizontal plane that includes the propeller axis.
In a ship located in the vicinity, the joint is formed at the nozzle bottom.
A ship characterized by bringing the propeller closer to the propeller than the tip of the part . 2. A method nozzle <br/> le provided in the front of the propeller, it is fixed to the hull through upper and lower two support members, the rotational direction opposite to the direction of twist of the propeller to the support member 2. The ship according to claim 1 , wherein the ship is provided.