9results about How to "Good drag reduction effect" patented technology

The application provides a kind of mixed laminar flow control tail optimization design method of comprehensive multi-condition and multi-constraint, comprising the following steps: according to the optimization target and constraint condition of multiple actual conditions of vertical tail, the optimization mathematical model of vertical tail is established;Design variables are constructed;The design variables include vertical tail geometric parameter design variables and vertical tail suction coefficient design variables;Based on the vertical tail reference configuration, the optimization design space of each design variable is determined;Optimization design is carried out.The application has good multi-condition and multi-constraint processing capability, can consider the balance of friction resistance and pressure difference resistance in optimization design, while ensuring that the stall characteristics of vertical tail do not deteriorate during take-off and landing stage, and the laminar flow range of airfoil does not change abruptly under small side slip state, and can consider various complex engineering constraints, thereby effectively improving the drag reduction effect of mixed laminar flow control tail, and making the design result more in line with actual engineering needs.

The invention relates to the technical field of pipelines, discloses a turbulence inhibitor of airflow, preparation and application of the turbulence inhibitor and a gas conveying method, and aims to solve the problem of over-high energy consumption caused by pipeline friction resistance in pipeline transportation of gas. The turbulence inhibitor comprises microparticles, the length of the microparticles is larger than or equal to eta and smaller than or equal to Lx, and Lx is the turbulence integral scale; eta is the Kolmogorov scale, eta = (v3 / epsilon) 1 / 4, and v is the kinematic viscosity of the airflow; epsilon is the turbulent flow energy dissipation rate. The turbulence inhibitor has the advantages of being high in applicability, excellent in drag reduction effect, economical, capable of saving energy and the like.

This invention discloses a variable cross-section tail wing suitable for FSAE racing cars, comprising a variable cross-section wing assembly, an upper sparsity wing, a first lower sparsity wing, a second lower sparsity wing, and endplates. The variable cross-section wing assembly consists of a main wing, a first flap, and a second flap; all three wings are variable cross-section wings. The variable cross-section wing is a small, continuous section raised at mid-span. The main wing, the first flap, and the second flap are sequentially mounted between the two endplates, roughly diagonally distributed, with the second flap featuring a grunt flap. The upper sparsity wing is mounted on the corner of the endplate, while the first and second lower sparsity wings are located near the bottom of the endplate. There are two endplates, symmetrically mounted on both sides, each featuring louvers, an outer edge flange, a leading edge notch, a trailing edge notch, and guide strips. The variable cross-section wing can reduce the turbulence caused by the headrest and minimize airflow slippage in the spanwise direction, resulting in a more uniform pressure distribution on the wing surface. The louver structure also reduces drag.

This invention discloses a method for preparing a superhydrophobic drag-reducing coating and its application in a manta ray-inspired submersible prototype, belonging to the technical field of underwater drag reduction and surface functional materials. The method includes: dispersing micron-sized SiO2 and nano-sized SiO2 in ethyl acetate to obtain a first dispersion; dispersing PDMS in ethyl acetate to obtain a second dispersion; mixing and stirring the first and second dispersions, then adding a curing agent and long-chain perfluoroalkyl silane PFDTES, followed by spraying and curing to obtain a PFDTES-PDMS@SiO2 coating. This invention achieves a water contact angle >150° and a roll-off angle <9° through the synergistic effect of PFDTES long-chain fluorination modification, PDMS flexible bonding, and the micro / nano dual-scale SiO2 hierarchical structure. In the manta ray-inspired submersible application, a drag reduction rate of 14.43% is achieved at a flow rate of 0.5 m / s, and the performance remains stable after 24 hours of dynamic water flow impact. This invention features a simple process, controllable cost, and is suitable for drag reduction functionalization of complex curved underwater equipment.

The application discloses a preparation method of ultrahigh molecular weight poly-alpha-olefin, which uses one or more alpha-olefins as polymerization monomers, and carries out polymerization reaction under the action of a catalyst at-30-30 DEG C; the catalyst comprises a main catalyst, a cocatalyst and an external electron donor; the main catalyst is a solid catalyst component, which comprises magnesium, titanium, chlorine and an internal electron donor, and the mass ratio of the four is 1:10-100:20-400:1-5; the internal electron donor contains at least one dihydric alcohol ester compound; the cocatalyst is an alkyl aluminum compound; the external electron donor is selected from organosiloxane; and the molar ratio of the main catalyst (calculated according to titanium): the cocatalyst (calculated according to aluminum): the external electron donor (calculated according to silicon) is 1:10-500:0-500. The poly-alpha-olefin prepared by the method has a weight average molecular weight close to 10 million, and the drag reduction agent prepared from the poly-alpha-olefin has excellent drag reduction performance.

An arc plasma-enhanced trench turbulent friction drag reduction device is provided, comprising a trench wall (1) and an arc electrode assembly (2). The trench wall (1) is formed by multiple trenches extending along the flow direction and equidistantly distributed along the spanwise direction. The arc electrode assembly (2) is arranged in an array on the trench wall (1). A corresponding drag reduction method is also provided: a sensor is placed in the flow field to collect flow field data and inputs the data into a controller; the controller analyzes the data and selects the working mode and parameters accordingly; the sensor collects flow field data again to gather flow field information after arc discharge; the controller analyzes the data again, measures the surface friction resistance, and compares the change in friction resistance before and after arc discharge. If the expected drag reduction effect is achieved, the operation ends; otherwise, it returns to the second step to select a new working mode or discharge state. This invention combines actively controllable arc plasma discharge with passive trench flow control technology, which can achieve effective drag reduction under complex inflow conditions in actual flight.

The application discloses a liquid static pressure bearing with oil sealing surface air cushion drag reduction structure, which comprises a bearing body, an oil sealing surface air cushion drag reduction structure, a circumferential oil return groove and an axial oil return groove. A plurality of oil sealing surface air cushion drag reduction structures are arranged on the circumferential and axial holes of the bearing body. Each oil sealing surface air cushion drag reduction structure is composed of a rectangular oil sealing surface, a rectangular oil inlet groove, an oil inlet hole and a plurality of air inlet holes. The air inlet holes are densely distributed on the rectangular oil sealing surface close to the rectangular oil inlet groove. An air flow control unit is arranged in each air inlet hole. The circumferential oil return groove separates the circumferentially distributed oil sealing surface air cushion drag reduction structures, and the axial oil return groove separates the axially distributed oil sealing surface air cushion drag reduction structures. The oil sealing surface air cushion drag reduction structure can be widely applied to liquid static pressure linear bearings, radial bearings and thrust bearings, has good drag reduction effect and compact structure, and can obtain a liquid static pressure bearing with low heat generation, high stiffness and super-precision.

The application discloses a bogie bottom drag reduction cladding plate and a high-speed train bogie, and the cladding plate comprises a torsion bar cladding plate for cladding a torsion bar of a bogie frame, a first cladding plate for connecting a cross beam on one side of the torsion bar, and a second cladding plate for connecting a cross beam on the other side of the torsion bar. The first cladding plate and the torsion bar cladding plate form a first flow guide slope, the second cladding plate and the torsion bar cladding plate form a second flow guide slope, and the flow guide directions of the first flow guide slope and the second flow guide slope are symmetrically arranged. The application guides the airflow originally acting on the region near the center pin hole and the torsion bar to the lower side of the torsion bar cladding plate, optimizes the partial cladding and flow guide of the originally complex and abrupt bottom profile near the center pin hole and the torsion bar, forms a relatively continuous bottom flow guide surface, weakens the direct interference between the airflow and the complex components of the bottom, reduces the local flow separation, backflow and vortex intensity, improves the bogie bottom flow field distribution, and further achieves the purpose of reducing the aerodynamic drag of the bogie region.