Structural Design And Flow Field Analysis Of3-Dimensional Current Sensor For Measuring Upwelling

The development and utilization of marine resources has been rapidly developed inrecent years with the implementation of national marine strategy. Current measurementtechniques become more important because of the conventional flow measurementinstruments can not meet the growing demand for marine science and technology.Three-dimensional current velocity vector has a big difference between eachdimension component. Through the domestic and overseas research status of currentsensors we found that there is no better way to fulfill the velocity measurement whichhas great difference between three-dimension. The key issues of the research aredesigning and optimizing the structure and measuring devices of the sensor. A newthree-dimensional ocean current sensor is designed based on the simulation of flowaround classical models which can meet the measurement requirements thatthree-dimensional, transient, large differences dimensional velocity and providesupport for the acquisition of deep-sea flow.Lined with the structural design of three-dimensional ocean current sensor and basedon the decomposition of three-dimensional velocity vector, the difference dimensionalstructure design method is proposed that can measure three-dimensional flowvelocity.Variations of drag and lift of the sphere and disc with flow velocity areobtained through numerical simulation of three-dimensional flow around a sphere andlongitudinal flow around a thin disc by Fluent. A new type of three-dimensional oceancurrent sensors is designed by discussing the impact of fixed cylindrical rod to the flowaround a sphere and considering the deep-sea measurement requirements. Thehorizontal force transmission mechanism adopts a sphere structure and vertical forcetransmission mechanism uses a thin disc structure.Variations of flow around combination model with drag and lift of the sphere anddisc at different speeds are discussed through the numerical simulation of the flowaround the sensor structure. Discussing the influences on drag of the sphere and lift ofthe disc of flow around the combination with the comparison of flow field around asingle-ball or single-disc. The feasibility of the combinational structural design isverified.Strain sensor principle is used to design the force sensing unit. The size of elasticbeams of horizontal force sensing unit is optimized by Orthogonal Test and a micro-power amplifier is designed based on leverage with the usage of flexible hinge.The relationship between maximum strain and flow velocity is got by finite elementanalysis. The sensor can measure tiny upwelling—the magnitude of10-3mm/s，andquite different velocity between three-dimension by estimating the flow measurementrange.