CN201520396U - Transitional air bubble drag reduction ship - Google Patents

Abstract

Transition-grade air bubble drag-reducing ship, the bottom of the ship is equipped with a shallow step of jetting, and an air cavity is installed in the wall of the step. The bilge part is a pointed bilge with a downward pressure, and the downward pressure angle is 20-60 degrees. The height of shallow faults is 0.05-0.5 times the thickness of the local boundary layer, and the longitudinal position of shallow faults is 30-40% Lbp from the forward perpendicular. At the same time, the aspect ratio and slenderness coefficient of the original transitional boat are kept unchanged, and its wave-making resistance characteristics and other performance characteristics are not changed. It has good low wave resistance performance, seakeeping performance, bubbles are controlled within the boundary layer, good performance of bubble longitudinal movement, bubbles are not easy to escape in the bilge, and the drag reduction rate of bubbles is above 15%. Suitable for high-speed ships on water.

Description

Transitional air bubble drag reduction ship

technical field

The utility model relates to a water carrier, in particular to a drag-reducing ship with air bubbles.

Background technique

Bubble drag reduction, air film drag reduction, and microbubble drag reduction all use air bubbles or air film to change the density of the medium and change the boundary layer structure on the surface of the boat to reduce frictional resistance. Due to the law of bubble or air film movement, it is the flat-bottomed ship that is most likely to achieve high-efficiency bubble drag reduction. Therefore, research on bubble drag reduction both at home and abroad starts with planing boats with relatively large flat bottoms, and has achieved relatively high drag reduction. blocking effect.

Due to the different relative speeds of ships, there are many requirements for performance (in addition to rapidity, seakeeping, stability, maneuverability, etc. should also be considered), therefore, the requirements for the scale and characteristic line of ships are different. Most high-speed boats are in the category of transitional boats.

Since the characteristics of transitional boats are large ratio of length to width, slender hull, long distance of air bubbles moving in the longitudinal direction, it is difficult to maintain the concentration of air bubbles in the longitudinal direction; in addition, due to the characteristics of waves, the bottom of the boat has a horizontal slope, and the air bubbles are not easy to maintain. Hold, there is a lateral escape phenomenon. The characteristics of transition-class boats are unfavorable to bubble movement and maintenance, so research on bubble drag reduction for transition-class boats has not been reported at home and abroad.

Contents of the invention

The technical problem to be solved by the utility model is: to provide a boat that has the same length-to-width ratio and slenderness coefficient as the traditional transitional boat, does not change the wave-making resistance characteristics and other performance characteristics of the original ship, and rationally arranges the longitudinal position of the bubble generator. The outflow and resistance performance of the bubbles are guaranteed in the form of shallow breaks. The rise angle of the bottom of the boat is uniform and excessive, and the bilge is pressed down into a sharp bilge to overcome the lateral slope of the bottom of the boat, which is beneficial to the longitudinal movement of the bubbles and reduces the horizontal escape of the bubbles, improving the effect of drag reduction. Transition-level air bubble drag-reducing ship.

The technical solution adopted by the utility model to solve the problems of the technologies described above is:

不变，不改变其兴波阻力特性及其它性能特点。The bottom of the ship is equipped with shallow faults with air jets. The bilge part of the ship is a pointed bilge with downward pressure. The downward pressure angle is 20-60 degrees. The height of shallow faults is 0.05-0.5 times the thickness of the local boundary layer. The longitudinal position of shallow faults is 30-40% Lbp from the forward perpendicular. At the same time, the length-to-width ratio (L/B) and slenderness coefficient of the original transitional boats are maintained

No change, no change in its wave-making resistance characteristics and other performance characteristics.

The distribution of the ramp angle is: when the station number is 0, the bottom rise angle β is 5; when the station number is 0.5, the bottom rise angle β is 6.2; when the station number is 1, the bottom rise angle β is 7.8 ; When the station number is 2, its bottom rise angle β is 10.4; when the station number is 3, its bottom rise angle β is 13; when the station number is 4, its bottom rise angle β is 15.1; when the station number is When the station number is 5, its bottom rise angle β is 16; when the station number is 6, its bottom rise angle β is 17; when the station number is 7, its bottom rise angle β is 21; when the station number is 8, its bottom The rise angle β is 31; when the station number is 9, its bottom rise angle β is 48; when the station number is 9.5, its bottom rise angle β is 53; when the station number is 10, its bottom rise angle β is 54 ;

不变，不改变其兴波阻力特性及其它性能特点。At the same time, the length-to-width ratio (L/B) and slenderness coefficient of the original transitional boats are maintained

No change, no change in its wave-making resistance characteristics and other performance characteristics.

The utility model has the following advantages:

1. Low wave resistance;

2. Good seakeeping performance;

3. Better bubble control: the bubbles are controlled in the boundary layer, the longitudinal movement of the bubbles is smooth, the coverage of the bubbles is large, the bubbles are not easy to escape from the bilge, and the drag reduction rate of the bubbles is over 15%;

4. Bubbles have less influence on the propeller;

5. The boat shape is simple, easy to build boats and improve the drag reduction rate of air bubbles.

Description of drawings

It is a structural schematic diagram of the utility model.

In the figure, 1. shallow fault level, 2. air cavity.

Detailed ways

According to the law of bubble movement, the ship shape with excessively uniform bottom lift angle change is adopted, taking into account the high efficiency of bubble drag reduction and the influence of bubbles on propulsion performance, and the longitudinal position of the bubble generator is reasonably selected. According to the concept that the influence of air bubbles is within the thickness of the boundary layer, and considering the feasibility of the process, the ship is determined to be a shallow-break ship type. The height of the step is determined according to the actual height of the bubble nozzle and the feasibility of the process. An air cavity is installed in the step wall, and air is compressed into the cavity by means of a compressor or the like. The bilge is designed to have a pointed bilge for pressing down.

The main technical parameters are as follows:

Shallow fault height: 0.05 to 0.5 times the thickness of the local boundary layer

Longitudinal position of fault level: 30-40% Lbp from the forward perpendicular

Bilge downward pressure angle: 20～60

The distribution of the ramp angle is: when the station number is 0, the bottom rise angle β is 5; when the station number is 0.5, the bottom rise angle β is 6.2; when the station number is 1, the bottom rise angle β is 7.8 ; When the station number is 2, its bottom rise angle β is 10.4; when the station number is 3, its bottom rise angle β is 13; when the station number is 4, its bottom rise angle β is 15.1; when the station number is When the station number is 5, its bottom rise angle β is 16; when the station number is 6, its bottom rise angle β is 17; when the station number is 7, its bottom rise angle β is 21; when the station number is 8, its bottom The rise angle β is 31; when the station number is 9, its bottom rise angle β is 48; when the station number is 9.5, its bottom rise angle β is 53; when the station number is 10, its bottom rise angle β is 54 ;

Main scale Loa＝40m Lw＝35.535m Lbp＝35m B＝7m T＝1.2m Scale ratio Lw/B＝5.08

Claims (2)

1. transstage bubble drag-reduction ship, it is characterized in that: hull bottom is provided with jet shallow disconnected level (1), in shallow disconnected level (1) wall air cavity (2) is installed, bilge portion has the hard chine that presses down, press down angle at 20～60 degree, shallow disconnected level highly is 0.05～0.5 times of local boundary layer thickness, and shallow disconnected level lengthwise position is 30～40%Lbp apart from fore perpendicular.

2. transstage bubble drag-reduction ship according to claim 1, it is characterized in that: its ramping angle is distributed as: when station number was 0, lift angle β was 5 at its end; When station number was 0.5, lift angle β was 6.2 at its end; When station number was 1, lift angle β was 7.8 at its end; When station number was 2, lift angle β was 10.4 at its end; When station number was 3, lift angle β was 13 at its end; When station number was 4, lift angle β was 15.1 at its end; When station number was 5, lift angle β was 16 at its end; When station number was 6, lift angle β was 17 at its end; When station number was 7, lift angle β was 21 at its end; When station number was 8, lift angle β was 31 at its end; When station number was 9, lift angle β was 48 at its end; When station number was 9.5, lift angle β was 53 at its end; When station number was 10, lift angle β was 54 at its end.

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