A New Flow-Meter Design Based On Fiber Bragg Gratings

Flow rate same as temperature, liquid level, and pressure, is important data that is commonly measured in industry. At the same time, high accuracy of flow measurement is fundamental for economic account settlement in Industry. It also guaranteed the high efficiency of productivity in enterprise. The flow measurement is closely connected with energy quantification, environmental protection, and scientific research. Especially when the level of energy consumption and the degree of production automation in industry are higher than ever in today’s society, the influences and effects of flow measurement in national economics are even more prominent. The fiber grating is accomplished by creating a periodic distribution in the fiber core to form spatial phase grating. It essentially formed a narrow band(transmissive or reflective) filter or mirror within the core. The advantage of using Fiber grating are: reflection of a wide range of bandwidth; Small in size; minimum additional loss;easy to integration into a wide variety of systems; Ideal for hash environment Fiber Bragg grating is used in a number of applications, including telecommunication(fiber lasers, Fiber filters, etc.) and fiber sensors(straining, temperture, speed, and accelaration measurement,ect.)This article started with introducing the research background and significance of the study. It then introduced several new sensor instruments that integrated the technology of fiber grating and flow measurement. Followed with basics theory of Fiber Bragg Grating and theories of applying target flow-meter in measurement. By integrating these two theories,the author analyzed and established the specific equation for the center wavelength and flow equation. Based on this theoretical foundation, the author designed a new type of fiber grating sensor with target flow-meter. The sensor was attached on the triangular cantilever by high temperature resistant AB glue. When the cantilever was deformed by the impact of liquid, the center wavelength of the FBG would be drifted.Construction of the experimental platform,using FBGA demodulator instrument.The author observed and analyzed the changes of the center wavelength of FBA, and thus analyzed and determined the function of the flow and the amount of the shift of center wavelength of FBG. This article also established the internal connection between these two. Therefore, the flow can be estimated by calculating the quantity of the shift of the center wavelength of FBG.In order to overcome the problems of temperature cross-sensitivity, this study utilized two identical FBG, with the same center wavelength. It application is effective to temperature compensation. This type of flow senor can be used in an environment of which temperate has significant impact on flow capacity.