Research On Monitoring System Of Primary Air Velocity Based On Ultrasonic Method

Along with the energy crisis and the rapid development of electric power industry, the level of automation of power plant operation, as well as safety and economy of operation, has raised to a higher demand.In China's thermal power plants, the pulverized coal boiler is used in the warehouse-style. We use hot air to send powder. Square layout of the burner is expected to establish a good aerodynamic condition, burns steady, it must maintain the four corners of primary air reasonably. Therefore, an accurate, real-time monitoring of the primary air velocity will directly affect the boiler combustion conditions. It is of great significance to guide the optimal operation and ensure the safety.After this paper introduces the various problems lying in traditional on-line monitoring technology, it proposes an on-line monitoring method of primary air velocity based on ultrasonic sensors. Through the deep study of the basic principles of ultrasonic velocity measurement, this paper proposes a method which combines the improved time difference method and correlation method. In order to verify the correctness of this approach, we design the system hardware and software. Based on the idea of flexible circuit design, we use FPGA+DSP hardware to improve system scalability and extensibility, and use MCGS to develop a man-machine interface, completing the on-line monitoring tasks.After simulation tests, this system opposed to the traditional velocity measuring system of the dynamic pressure is known to be precise and real-time character, hence in good application. It can help operators keep abreast of the boiler primary air velocity conditions, in order to take relevant measures before the flame center skews or other undesirable conditions happen, thus enhancing the safety of plant unit.