34results about How to "To achieve the purpose of drag reduction" patented technology

The invention discloses a speed boat and a manufacturing method thereof and relates to the field of water surface boats. The speed boat comprises a hull. Floating barrels are symmetrically arranged on the two sides of the hull along knuckle lines of the hull. The floating barrels are closed long tank bodies with cavities formed inside. The bottoms of the outer side faces of the long tank bodies are bent downwards. The manufacturing method of the speed boat includes the steps that a metal plate is cut and developed into the hull with the floating barrels, side floating barrels communicating with the floating barrels of the hull are welded to the two sides of a bow, the side faces of the bow are welded to the side walls of the hull, and finally, a metal plate is pressed into a tail seal to be welded to the tail of the hull. Compared with the prior art, due to the fact that the closed floating barrels with the cavities formed inside are symmetrically arranged at the positions of the knuckle lines of the hull on the two sides of the hull, in the static floating process, part of the floating barrels are submerged in water, the reserved buoyancy of the floating barrels is greatly improved, the draught of the hull is greatly reduced, and the transverse stability performance is improved; when the speed is increased, the floating barrels gradually jump out of the water surface, resistance is reduced, and a rapid sailing target is achieved; and a rigid whole is composed of the floating barrels and the hull, and the structural strength is enhanced.

The invention discloses a novel volute-less centrifugal ventilator with resistance reduction grooves. The novel volute-less centrifugal ventilator with the resistance reduction grooves comprises a wheel disc, a wheel cover, blades and the resistance reduction grooves; the blades are welded between the wheel cover and wheel disc, the blades are uniformly distributed around the axial line of the wheel cover, the resistance reduction grooves are milled after processing the blades, the wheel disc is disc-shaped, and a flange structure is arranged at the middle for mounting a motor shaft; the sections of the blades are the same curves, the parts in contact with the wheel cover conform to the molded line of the wheel cover, the resistance reduction grooves are rectangular, from 50% part of the molded line of each blade, the resistance reduction grooves are uniformly distributed on the pressure surfaces of the blades from the blade inlet to the outlet, there are 12 resistance reduction grooves, the gap between the resistance reduction grooves is 0.21 delta, each resistance reduction groove is 0.125 delta in depth and 0.25 delta in width, delta is the blade thickness, and the length direction of each resistance reduction groove runs through the whole blade. The novel volute-less centrifugal ventilator with the resistance reduction grooves reduces turbulent dissipation so as to reduce resistance, and the novel volute-less centrifugal ventilator with the resistance reduction grooves is capable of reducing the power consumption and improving the efficiency of the volute-less centrifugal ventilator.

The invention discloses a plasma suction device that can be used for drag reduction of airfoils. It includes an insulating shell, and a funnel-shaped cavity is provided at the center of the insulating shell. The wide mouth of the funnel-shaped cavity in the insulating shell is The end is provided with an annular first insulating medium layer, the center of the first insulating medium layer is provided with a disc-shaped second insulating medium layer, and there is an annular gap between the second insulating medium layer and the first insulating medium layer , the annular gap forms a suction hole, the first insulating medium layer is connected to the second insulating medium layer through several connecting rods; the narrow end of the funnel-shaped cavity in the insulating shell is provided with a one-way exhaust valve; the first insulating medium layer The lower surface of the medium layer is radiated with a lower electrode, and an upper electrode is buried inside the second insulating medium layer; the upper electrode is grounded, and the lower electrode is connected with a negative DC pulse high voltage. The plasma suction device of the invention can reduce the frictional resistance on the surface of the wing.

The invention discloses a damping device and a damping method based on the periodical step cylindrical surface. According to the damping device and the damping method, through the periodicity of reverse rotating Taylor vortices under the Taylor-Couette flow conditions, the size of the Taylor vortices is changed, and the number of the big-size Taylor vortices is reduced. By arranging periodical cylindrical surfaces with different radii on the inner wall of a shaft sleeve in the axial direction and controlling the height of the liquid level in the gap between a rotary shaft and the shaft sleeveduring Taylor-Couette flow, the rotating speed of the rotary shaft and the injection speed of working fluid are controlled to achieve the hysteresis effect of the Taylor vortices under different injection speeds. By slowly increasing the liquid level height of the working fluid between the rotary shaft and the shaft sleeve, the size and number of the Taylor vortices are changed, so that the size of the Taylor vortices is changed, and the number of the big-size Taylor vortices is reduced. Accordingly, resistance of the rotary shaft is reduced. The damping device has the characteristics that thedamping device is fast and convenient to manufacture and low in cost, and the damping method is remarkable in damping effect.

The invention discloses an underwater drag reduction bionic micro-nano structure which comprises U-shaped structures of bionic dolphin spine skin and sawtooth structures of bionic mosquito stylets. Aswimming bladder comprises a conical body structure at the front end and a cylindrical body structure at the rear end, the sawtooth structures are distributed on the surface of the conical body structure, and the U-shaped structures are distributed on the surface of the cylindrical body structure. According to the invention, the micro structures of bionic dolphin spine skin and the micro structures of bionic mosquito stylets are adopted, and the novel micro-nano combined structure is formed by combining the two micro-structures and is applied to the swimming bladder, and a good drag reductioneffect is achieved.

The invention claims a composite gas drag reducer and a preparation method thereof. The method comprises the following step of: reacting organic dibasic acid or organic binary acid anhydride, organic amine and monocarboxylic acid with a long carbon chain, thereby obtaining the composite gas drag reducer, wherein the specific steps the reaction are as follows: (1) reacting the organic dibasic acid or organic binary acid anhydride and the organic amine in an inert atmosphere, (2) adding the monocarboxylic acid with the long carbon chain to the reaction system of the finished reaction in the step (1), thereby obtaining the composite gas drag reducer via reaction. The composite gas drag reducer is obvious in drag reduction of the pipeline gas and energy conservation, and has the advantages of cheap and easily available raw material, simplicity in operation, mild reaction conditions, simple processes, low equipment requirements and easiness for industrial production.