CN2377170Y - Tailpiece ship - Google Patents

Abstract

The utility model relates to ship manufacturing technology. The stern of the ship is designed so that the vertical surface connects with the horizontal ship bottom plate, the stern is provided with an empennage, and an air channel is provided between the stern and the empennage, and the underwater part of the empennage is designed as a paraboloid, so that when the ship is sailing, the tail does not generate pressure less than atmospheric pressure. Negative pressure area, while the negative pressure area is generated when the conventional ship stern is sailing, so that the average pressure of the entire stern is negative pressure, so the utility model can reduce the pressure difference between the bow and the stern when the ship is sailing, and the speed of the ship can be increased. economic and social benefits.

Description

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The utility model relates to ship manufacturing technology.

In the prior art, ships are mainly divided into two types: floating fast ships and displacement conventional ships. Float-up fast boats include hovercraft, hydrofoil boats, and gliding boats. When these ships sail, all or part of them rise above the water surface to eliminate or reduce the pressure difference resistance generated by the water on the bow and tail when the ship sails to increase the speed. Due to the manufacturing cost Expensive, poor stability when sailing and cannot be widely promoted, let alone be made into a large ship. Conventional ships mainly have bulbous bows with large tonnage and wedge-shaped tails, as shown in Figure 1, and barge-shaped bows and tails with small tonnages, as shown in Figure 2. The navigation resistance of this type of conventional ships includes air resistance and water viscosity. The stagnation force, the head-to-tail pressure difference resistance, etc., among which the pressure difference resistance is the main factor that the ship's speed cannot be increased. At present, the bow of conventional ships has undergone long-term improvement (such as the bulbous bow shape of large-tonnage ships), and the bow pressure has decreased, but the tail pressure cannot be increased, and the pressure difference resistance between the bow and the tail cannot be significantly reduced. Therefore, it is necessary to increase the tail pressure. Can effectively increase the speed.

The purpose of the utility model is to improve the shape of the stern, and add an empennage at the stern, and use the empennage to receive the kinetic energy left by the stern when the ship sails to increase the pressure of the stern, thereby reducing the pressure difference resistance and increasing the speed. In order to show that the pressure at the stern of the empennage ship is greater than that of the conventional ship, a qualitative analysis is first made on the magnitude and distribution of the pressure at the stern of the conventional ship.

Fig. 3 is a tail pressure magnitude and distribution diagram when a barge (middle longitudinal sectional view) sails at a speed V. The thin solid line in the figure is the boundary line of the pressure area, the thick solid line is the tail contour line, and the dotted line is the horizontal surface line. There is a shaded area between the thin solid line and the contour line. The arrow pointing to the contour line in the shaded area is greater than one standard atmospheric pressure, and the arrow pointing to the thin solid line in the shaded area is less than one standard atmospheric pressure. This is called a negative pressure area. The current of the water moves forward with the ship and consumes energy in the form of eddies. The length of the arrow segment represents the absolute value of the pressure. The thin solid line intersects the contour line at point N. The pressure at point N is equal to a standard atmospheric pressure. When the ship accelerates forward, point N moves down, and vice versa. When it is zero, point N rises to the horizontal plane line, that is to say, there is no negative pressure area at the tail when the ship is stationary, and the ship must have a certain speed so that the sum of the pressures in the upper and lower pressure areas of point N is a standard atmospheric pressure, which is greater than this The sum of velocity and pressure must be less than one standard atmospheric pressure. To prove this conclusion, it is only necessary to prove that the area above point N is a negative pressure zone when the ship is sailing, and a simple experiment may be done to prove it.

Connect a hose to the water faucet, open the water valve, and let the water flow out from the horizontal nozzle at a certain speed, as shown in Figure 4, you can see the state of the water after it flows out of the nozzle, and then use a barge similar to the shape of the tail of the barge The thumb is attached to the mouth of the nozzle, as shown in Figure 5, it can be seen that the water flow rises along the thumb, and the pressure of the area where the water flow rises is a negative pressure area that is less than a standard atmospheric pressure. This is because the air under the thumb is taken away by the water flow ( There is friction when air and water move relative to each other), and the formed negative pressure zone is filled by water, and this negative pressure zone expands with the speed of water flow. If the nozzle is tilted up at an angle to do the same test, the result is the same. This just proves the above-mentioned conclusion that the area above the N point is a negative pressure zone, and also proves that after the tail geometry of the underwater part of the ship is determined, there is always a certain speed, so that the average pressure of the tail is equal to a standard atmospheric pressure, and greater than this determined The speed is less than one standard atmospheric pressure, and the greater the speed, the smaller the average pressure. Here it is one of the main reasons why the ship cannot effectively increase the speed of the ship. The wedge-shaped stern is the same, so I won't repeat them here.

的速度航行时，以船为参考系，可看出尾流全部脱离尾板，自N点以抛物线状向后射流，见图中的细实线(这里没有考虑船尾两侧水流向中间流动，以及船底水流粘滞力对尾流形状的影响，因为这种影响是次要的)。这种尾流是一种由势能转为动能的能量，如不利用，将在船尾以波浪形式消耗掉。因此在船尾设置一尾翼来接收能量，如图7，使船尾部平均压强增加，首尾压差减小，达到有效提高船速的目的。The utility model is that the conventional stern is changed into a stern board and the bottom plate is vertically connected, and the connection point N is a sharp angle, as shown in Figure 6, and the design draft is h. When the ship takes

When sailing at the speed of , taking the ship as the reference system, it can be seen that the wake completely breaks away from the stern flap and jets backward in a parabolic shape from point N, as shown in the thin solid line in the figure (here, the flow of water on both sides of the stern to the middle is not considered, and the effect of the viscous force of the bottom water flow on the shape of the wake, since this effect is secondary). This wake is a potential-to-kinetic energy that, if not utilized, will be dissipated in waves at the stern of the ship. Therefore, an empennage is installed at the stern to receive energy, as shown in Figure 7, so that the average pressure at the stern increases, and the pressure difference between the fore and aft decreases, so as to effectively increase the speed of the ship.

Further description will be made below by means of drawings and examples.

Fig. 8 is a schematic diagram of an embodiment of the utility model.

In the figure (1) is the hull, an empennage (3) is arranged behind the stern (2), and an air passage (4) is arranged between the stern and the empennage, the air passage can make the atmosphere pass smoothly and reach the NA. The stern and the empennage are connected by rods or other means, as long as the rigidity can be guaranteed, it is not shown in this figure. The part below the empennage draft is designed as an empennage paraboloid (5), and the empennage parabola is determined according to the design ship speed V, which is gentler than the wake paraboloid (6) formed by the speed V navigation of a tailless ship. When the ship accelerates to V at zero speed, the water level of the air channel also drops from the horizontal plane to NA. In this state, the pressure on the empennage parabola is shown in the shaded area in the figure, which is greater than or equal to the atmospheric pressure (two points AB equal to atmospheric pressure).

According to the schematic diagram of Fig. 8 (middle longitudinal sectional view), this empennage ship can be made into a wider, flatter hull without affecting the empennage function.

If the power of the newly added ship makes the speed V of the ship increase, there is always a speed Vm (Vm>V), so that the wake under the empennage parabola is completely separated from the parabola, and at this time the space between the empennage parabola and the wake parabola is filled with air ( As shown in Figure 9), and communicate with the atmosphere behind the air channel and empennage. The pressure of the empennage parabola in this state is equal to a standard atmospheric pressure. If the air channel is closed, the ship starts to have a speed relative to the still water, and point B will generate a negative pressure zone, and expand to point A with the increase of ship speed until point N, which is the same as that of a conventional ship. Therefore, the combined use of the air channel and the empennage can effectively increase the speed of the ship.

In summary, the air channel and empennage are the key points of the utility model. Compared with the conventional ship, the stern of the utility model does not produce a negative pressure zone, so the tail pressure increases (compared with the conventional ship), and the pressure difference between the head and the tail is greatly reduced. The speed of the ship is reduced, the speed of the ship is effectively improved, and the manufacturing cost does not increase, and it can be widely used on ships of different sizes and tonnages, and the economic and social benefits are remarkable.

Claims (1)

The empennage ship includes an empennage behind the stern, which is characterized in that an air channel that can communicate with the atmosphere is arranged between the stern and the empennage, and the underwater part of the empennage is designed as an empennage paraboloid.

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