4results about How to "Good drag reduction effect" patented technology

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 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.