Ventilation drag reduction device and marine ventilation drag reduction system including same

A ventilation drag reduction device that is installed at a position flush with the bottom of a hull to form an insulating gas layer on the bottom of the hull, comprising a main housing, a first rectification assembly, a second rectification assembly, and a flow isolating assembly, wherein:

• along a direction from left to right, the main housing is composed of a first segment, a second segment, a third segment, and a fourth segment that are sequentially connected and communicated from end to end;
• along a direction from left to right, the longitudinal cross-sectional areas of the first segment and the third segment remain unchanged, while the longitudinal cross-sectional areas of the second segment and the fourth segment tend to be smaller;
• the first segment is configured as an inlet end, and a top wall thereof is provided with an air inlet;
• the first rectification assembly is composed of a plurality of first rectification plates vertically arranged in a cavity of the second segment and spaced apart in a left-right direction;
• a plurality of first ventilation holes are evenly distributed on the first rectification plate;
• the second rectification assembly is composed of at least one second rectification plate vertically arranged in a cavity of the third segment;
• a plurality of second ventilation holes are formed on the second rectification plate near a top wall thereof;
• the flow isolating assembly is arranged in a cavity of the third segment and located on the right left side of the second rectification assembly;
• the flow isolating assembly is composed of a plurality of flow isolating plates that are all parallel to the second rectification plate and are displaced from each other along the up-down direction;
• the fourth segment is configured as an outlet end, and a bottom wall thereof is provided with an air outlet;
• the ventilation drag reduction device further includes a rectification filler;
• the rectification filler is embedded in the cavity of the third segment, and is provided with a rectification flow channel which completely penetrates along its length direction;
• along a gas flow direction, the rectification flow channel is sequentially composed of a contraction cavity, a horizontal constant section cavity, and a down-folded exhaust cavity;
• the ventilation drag reduction device further includes a deflection plate;
• the deflection plate is hinged in the rectification filler to communicate or block the horizontal constant section cavity and the down-folded exhaust cavity;
• in a working state, high-pressure gas is continuously supplied to the air inlet, and the deflection plate performs a deflection motion under the action of an external gas thrust to communicate the horizontal constant section cavity and the down-folded exhaust cavity;
• in a non-working state, the supply of high-pressure gas to the air inlet is suspended, and the deflection plate is reset under the action of gravity to block the horizontal constant section cavity and the down-folded exhaust cavity;
• corresponding to the horizontal constant section cavity, an inclined limit wall is formed in the down-folded exhaust cavity;
• the deflection angle of the deflection plate is controlled between 0° and 60°;
• and when the deflection plate is horizontal against the inclined limit wall, the deflection angle of the deflection plate is 60°;
• the top wall of the fourth segment is arc-shaped, and the arc radius r is controlled at 300-350 cm;
• and
• the ventilation drag reduction device further includes a flow stabilizing assembly;
• the flow stabilizing assembly is arranged in the cavity of the fourth segment, and consists of a plurality of first horizontal flow stabilizing plates, second horizontal flow stabilizing plates, and third horizontal flow stabilizing plates that are displaced from and parallel to each other in a left-right direction;
• the first horizontal flow stabilizing plate and the third horizontal flow stabilizing plate are both fixed on a right side wall of the second rectification plate, and are kept in a non-abutting state with the top wall of the fourth segment;
• and the second horizontal flow stabilizing plate is fixed on the top wall of the fourth segment, and is kept in a non-abutting state with the second rectification plate.