Research On Measuring Principle And Structure Design Of New Thrust Flow Transducer

This paper is a technology applied research which is funded by two projects. The one is specialized research fund for the doctoral program of higher education of 2009 called "The Research of Application and Mechanism on All-weather Automatic Monitoring Hydrological Information Based on the Physical Property Difference of Air, Ice and Water"(Item Number:20091402110004).The other one is outstanding graduate innovation project in Shanxi province of 2009 called " The Research of Remote Telemetry System for Hydrological Information and Ice Disaster Based on GSM/GPR"(ItemNumber:80010402100171).Rivers, lakes and havens as water resources and important carrier of water environment are paid more attention by the society. River's water environment closely related to industrial and agricultural production and people's lives involved society, economic, resources, environment and other aspects. The management of river's water environment as a complex systemic project needs to use economic management, social management, capital investment, science and technology and many other means. In recent years, because of the emergence of serious big floods, new requirements of the hydrological forecast have been raised. Flow measurement is a very important project in hydrological forecast.In winter the Yellow River is covered with ice. It is difficult to measure velocity of water under ice sheet of rivers in the winter. Because the environment temperature is generally about 20 degrees below zero. In addition, water which is under ice sheet of rivers includes frazil slush. Most of flow meters are used to measure velocity of rivers which are not frozen. Literature search and actual survey results show that whether at home or abroad sub-ice current meter is hardly any.After referring to the measurement principles of current flow meters, the experimental apparatus of new thrust flow transducer based on the properties of particle phase is proposed in this paper. The traction cable's pull force which is given by the floating ball in the fluid is first measured by the experimental apparatus. Then the force situations of rigid floating ball are used to calculate fluid thrust on the floating ball. Finally, velocity can be gotten by empirical formula between fluid velocity and fluid thrust on the floating ball.Based on the above idea, the author designs the experimental device of new thrust flow transducer. The experimental device is made up with the sensitive components, the transfer structure and the displacement detection structure. A steel ball is the sensitive component of the experimental device; the sensitive spring and the traction wire compose the transfer structure of experimental device; laser, optical receiving device and dodging laser devices compose the displacement detection department.In addition, after finishing the design of experimental device of new thrust flow transducer, the on-site detection system of which MSP430F1611 microcontroller is the core is designed to complete real-time calculation of test data, display, storage and communication. The on-site detection system can communicate with upper management computer or water level and ice thickness sensor through the RS232 serial communication interface.The author develops real-time data acquisition program, data processing program, data display program, and data storage program in the MSP430 IAR Embedded Workbench environment.In December 2009 and March 2010, the experimental device of new thrust flow transducer is applied to engineering test about detection water flow below ice sheet of the Yellow River in Toudaoguai hydrological station which is in Tuoketuo county of Hohhot of Inner Mongolia. The data collected through on-site which is analyzed shows that the detection principle of the experimental device is feasible and the experimental device is simple and low cost. It can not only be used for automatic measuring in velocity of water including frazil slush which is under ice sheet of rivers, water channels, lakes and oceans in freezing conditions, but also be used for measuring in surface velocity of rivers, water channels, lakes and oceans. This provides a new detection technology to automatically detect the parameters of ice-water conditions.