Research And Design Of Partially Filled Pipe Electromagnetic Flowmeter

In the field of process control, measurements of flux, fluid-velocity and liquid level are necessary. The traditional flow-meter in partially filled pipe leads to erroneous results and even can be irritating to use. With intellectualization and informatization of modern production, the demand of measurements in multiphase flow and partially filled pipe has continued to pick up, especially in industries of sewage, oil and chemical materials. The related research is gradually becoming hot spot problems in flow-meter.According to the demand of flux's measurment, this dissertation develops an simplified and improved electromagnetic flow-meter based on the capacitance tomography technology. This flow-meter is able to make real time high-accuracy measurement to the liquid level, and also achieves the unfilled pipe flux value by integrating with the fluid-velocity of the electromagnetic flow-meter. Firstly, it discusses the sensor system of novel electromagnetic flow-meter, including its flow rate sensor and liquid level sensor. Based on the capacitance tomography technology, it constructs six electrodes with the same parameter between the insulation pipe's ektexine and pipe shield, which can be combined to form three liquid level sensors with different symmetric constructions. For measuring the tiny capacitance, it builds the data collection and signal processing system derived from the sensor chip PCap01 by the comparison of different measurements. In addition, it devises a mathematical model of liquid level measurement sensor system due to the capacitance's special symmetric construction, depending on the mathematical relation between capacitance and height. Then, it simulates a mathematical model mentioned above and obtains tendency of three capacitance following liquid level's changes. Moreover, it designs a software and hardware of partially filled pipe electromagnetic flow-meter system, including tiny capacitance collection system andfluid-velocity measuring system, which performs the novel prototype of partially filled pipe electromagnetic flow-meter.Eventually, it obtains a capacitance-liquid-level curve of three sensors in different height by examining prototypes. By comparing and analyzing the measuring and simulating results, the consequence suggests that measured results are in agreement with theory results in the tendency and laws. It proves practicality and worth of the novel design of measurement and the electromagnetic flow-meter. Meanwhile, there are many strengths of this meansurement, like wide measuring range, high sensitivity, less error by practice,following that it has a strong engineering practice signifficance.