CN107966234A - Based on stress distribution measuring device and method suffered by the film surface of optical fiber grating sensing - Google Patents
Based on stress distribution measuring device and method suffered by the film surface of optical fiber grating sensing Download PDFInfo
- Publication number
- CN107966234A CN107966234A CN201711188867.4A CN201711188867A CN107966234A CN 107966234 A CN107966234 A CN 107966234A CN 201711188867 A CN201711188867 A CN 201711188867A CN 107966234 A CN107966234 A CN 107966234A
- Authority
- CN
- China
- Prior art keywords
- fiber
- grating
- fiber grating
- optical fiber
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000009826 distribution Methods 0.000 title claims abstract description 47
- 239000013307 optical fiber Substances 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 15
- 239000000835 fiber Substances 0.000 claims abstract description 227
- 239000012528 membrane Substances 0.000 claims abstract description 162
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 56
- 230000008859 change Effects 0.000 claims abstract description 29
- 239000003292 glue Substances 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims description 51
- 238000009292 forward osmosis Methods 0.000 claims description 18
- 238000012545 processing Methods 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 7
- 239000012530 fluid Substances 0.000 claims description 2
- 238000002310 reflectometry Methods 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 238000005538 encapsulation Methods 0.000 claims 1
- 238000001914 filtration Methods 0.000 claims 1
- 230000003068 static effect Effects 0.000 abstract description 8
- 238000002347 injection Methods 0.000 abstract description 3
- 239000007924 injection Substances 0.000 abstract description 3
- 238000004806 packaging method and process Methods 0.000 abstract 1
- 239000002994 raw material Substances 0.000 description 19
- 238000005259 measurement Methods 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 239000012510 hollow fiber Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000009285 membrane fouling Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 238000001223 reverse osmosis Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000000108 ultra-filtration Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000013480 data collection Methods 0.000 description 2
- 238000010612 desalination reaction Methods 0.000 description 2
- 238000001471 micro-filtration Methods 0.000 description 2
- 238000001728 nano-filtration Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000003491 array Methods 0.000 description 1
- 239000003637 basic solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910021642 ultra pure water Inorganic materials 0.000 description 1
- 239000012498 ultrapure water Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
- G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
- G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
本发明公开了一种基于光纤光栅传感的膜面所受应力分布测量方法，步骤是：选择多根光纤光栅传感器，且其中任何两个光纤光栅传感器的中心波长相差不小于2nm，将多根光纤光栅传感器用单模光纤串联，对串联后的光纤光栅传感器施加预应力后使用UV胶固定在膜组件上，使每个光纤光栅传感器与膜面之间的距离在0‑1mm；将膜组件封装后与光纤光栅解调仪连接，利用光纤光栅解调仪自带的软件测得各光纤光栅传感器的中心波长的静态值和注水后的测量值和变化值，最终根据光线光栅的传感原理得到不同流速情况下膜面所受应力的分布情况，从而为进一步对膜面水力学状态的科学判断奠定了基础。
The invention discloses a method for measuring stress distribution on a film surface based on fiber grating sensing. Fiber Bragg grating sensors are connected in series with single-mode optical fibers, and after prestressing the connected fiber grating sensors, they are fixed on the membrane assembly with UV glue, so that the distance between each fiber grating sensor and the membrane surface is 0‑1mm; the membrane assembly After packaging, it is connected to the fiber grating demodulator, and the software of the fiber grating demodulator is used to measure the static value of the central wavelength of each fiber grating sensor and the measured value and change value after water injection, and finally according to the sensing principle of the fiber grating The distribution of stress on the membrane surface under different flow rates is obtained, which lays the foundation for further scientific judgment of the hydraulic state of the membrane surface.
Description
技术领域technical field
本发明涉及光纤光栅传感技术和膜法水处理技术领域，尤其涉及一种基于光纤光栅传感的膜面应力分布测量系统。The invention relates to the field of fiber grating sensing technology and membrane water treatment technology, in particular to a membrane surface stress distribution measurement system based on fiber grating sensing.
背景技术Background technique
膜技术因其节能、高效、经济、简单方便、无二次污染等一系列优点,在水处理中已被广泛地用于苦咸水淡化、海水淡化、工业给水处理、纯水及超纯水制备、废水处理、污水回用等。但在膜法水处理如正渗透过程中，存在浓差极化和膜污染的问题，使得通量下降。通过改变操作条件(水流速度和压力等)，可以减缓浓差极化和膜污染。如果能对膜界面的所受应力进行测量，则可有效了解膜面水力学情况，控制膜污染，科学的控制水力压力和能耗，指导优化组件结构等。由于膜分离过程中膜孔尺寸大都在微米级以下，同时污染和乘积在膜表面的颗粒物往往也在微米级以下，因此分析污染物在膜面上的水力学行为无法通过通常用在较大尺度流场的水力学分析设备而获得。目前，还没有有效地的手段可以直接对膜面的所受应力进行测量，通常，对膜分离过程中膜面的分析，大多数都是通过数值模拟和计算流体力学的方法，对膜面不同位置的流速、压力和浓度进行分析。Membrane technology has been widely used in water treatment for brackish water desalination, seawater desalination, industrial water supply treatment, pure water and ultrapure water because of its advantages of energy saving, high efficiency, economy, simplicity and convenience, and no secondary pollution. Preparation, wastewater treatment, wastewater reuse, etc. However, in the process of membrane water treatment such as forward osmosis, there are problems of concentration polarization and membrane fouling, which make the flux decrease. By changing the operating conditions (water velocity and pressure, etc.), concentration polarization and membrane fouling can be slowed down. If the stress on the membrane interface can be measured, it can effectively understand the hydraulics of the membrane surface, control membrane fouling, scientifically control hydraulic pressure and energy consumption, and guide the optimization of module structure. Since the membrane pore size in the membrane separation process is mostly below the micron level, and the particles that are polluted and accumulated on the membrane surface are often also below the micron level, the analysis of the hydraulic behavior of pollutants on the membrane surface cannot usually be done on a larger scale. Obtained by the hydraulic analysis equipment of the flow field. At present, there is no effective means to directly measure the stress on the membrane surface. Usually, most of the analysis of the membrane surface during the membrane separation process is through numerical simulation and computational fluid dynamics. The flow rate, pressure and concentration of the location are analyzed.
光纤光栅结构简单，质量轻，耐腐蚀，体积小并且本身即为敏感元件，对被测物体影响小，可以用来测量处于狭窄空间的物理量变化技术，并且能够通过分布式阵列进行多点测量。由于其在外形上可构造与膜面微流体行为更为接近的尺度范畴，因此使其直接测量膜表面的水力学行为的信息成为可能。Fiber Bragg grating has simple structure, light weight, corrosion resistance, small size and is itself a sensitive element, which has little influence on the measured object. It can be used to measure physical quantity changes in narrow spaces, and can perform multi-point measurement through distributed arrays. Because it can construct a scale category that is closer to the microfluidic behavior of the membrane surface in appearance, it is possible to directly measure the information of the hydraulic behavior of the membrane surface.
目前尚未有基于光纤光栅传感技术的膜面应力分布的测量系统。At present, there is no measurement system for the stress distribution of the film surface based on the fiber grating sensing technology.
发明内容Contents of the invention
针对现有技术正渗透膜处理技术中常见的板式正渗透膜组件，本发明将光纤光栅置于正渗透膜组件内，提供一种基于光纤光栅传感的膜面所受应力分布测量装置，可以实现对同一时刻膜面不同位置所受应力进行测量。本发明主要是基于光纤光栅的特性和传感原理，采用波分复用的方法，将多根光纤光栅串联后均匀分布在膜表面，对膜分离过程中膜面不同位置所受应力分布进行分析。Aiming at the plate-type forward osmosis membrane module commonly used in the prior art forward osmosis membrane treatment technology, the present invention places the fiber grating in the forward osmosis membrane module, and provides a device for measuring the stress distribution on the membrane surface based on fiber grating sensing, which can Realize the measurement of the stress on different positions of the membrane surface at the same time. The present invention is mainly based on the characteristics and sensing principle of fiber gratings, adopts the method of wavelength division multiplexing, and evenly distributes multiple fiber gratings in series on the membrane surface, and analyzes the stress distribution at different positions on the membrane surface during the membrane separation process .
为了解决上述技术问题，本发明提出的一种基于光纤光栅传感的膜面所有应力分布测量装置，其基本方案是，包括固定在膜组件内的多个光纤光栅传感器，所述多个光纤光栅传感器与所述膜组件相互之间的位置和连接关系是，多个光纤光栅传感器按照沿膜组件工作时的水流方向且在廊道区域范围内分布布置，多个光纤光栅传感器与所述膜组件的膜面之间的距离在0-1mm；各光纤光栅传感器的光栅波长互不重叠；多个光纤光栅传感器依次用单模光纤串联；串联后的光纤光栅传感器的一端为自由端，串联后的光纤光栅传感器的另一端通过单模光纤与一光纤光栅解调仪的输入端相连接；所述光纤光栅解调仪的输出端连接至一台计算机，所述计算机内安装有数据采集模块及数据处理模块，所述数据采集模块采用与所述光纤光栅传感解调仪配套的软件；所述数据处理模块根据光纤光栅的传感原理通过采集到的上述多个光纤光栅传感器的光栅波长的变化得出所述膜组件膜面所有应力的分布。In order to solve the above-mentioned technical problems, the present invention proposes a device for measuring all stress distributions on the membrane surface based on fiber grating sensing. The basic solution is to include a plurality of fiber grating sensors fixed in the membrane assembly, and The position and connection relationship between the sensor and the membrane module is that a plurality of optical fiber grating sensors are arranged along the water flow direction of the membrane module and distributed within the scope of the corridor area, and the plurality of optical fiber grating sensors and the membrane module The distance between the film surfaces is 0-1mm; the grating wavelengths of each fiber grating sensor do not overlap each other; multiple fiber grating sensors are connected in series with single-mode optical fiber; one end of the fiber grating sensor after series is a free end, and the The other end of the fiber grating sensor is connected to the input end of a fiber grating demodulator through a single-mode optical fiber; the output end of the fiber grating demodulator is connected to a computer, and a data acquisition module and a data acquisition module are installed in the computer. Processing module, the data acquisition module adopts the software matched with the fiber grating sensor demodulator; the data processing module passes the change of the grating wavelength of the above-mentioned multiple fiber grating sensors collected according to the sensing principle of the fiber grating The distribution of all stresses on the membrane surface of the membrane module is obtained.
本发明中提出的一种基于光纤光栅传感的膜面所有应力分布测量装置，其组合方案是，包括多套固定有多个光纤光栅传感器的膜组件，膜组件均为中空纤维膜或是平板膜或是卷式膜；每套固定有多个光纤光栅传感器的膜组件中，所述多个光纤光栅传感器与所述膜组件相互之间的位置和连接关系是，多个光纤光栅传感器按照沿膜组件工作时的水流方向且在廊道区域范围内分布布置，多个光纤光栅传感器与所述膜组件的膜面之间的距离在0-1mm；各光纤光栅传感器的光栅波长互不重叠；多个光纤光栅传感器依次用单模光纤串联，从而形成一套固定有多个光纤光栅传感器的膜组件；将各套固定有多个光纤光栅传感器的膜组件的光纤光栅的两自由端用单模光纤连接，连接方式是串联或并联或串并联；将连接后的多套固定有多个光纤光栅传感器的膜组件中的光纤光栅的一端通过单模光纤与一光纤光栅解调仪的输入端相连接；所述光纤光栅解调仪的输出端连接至一台计算机，所述计算机内安装有数据采集模块及数据处理模块，所述数据采集模块采用与所述光纤光栅传感解调仪配套的软件；所述数据处理模块根据光纤光栅的传感原理通过采集到的上述多个光纤光栅传感器的光栅波长的变化得出所述膜组件膜面所有应力的分布。A device for measuring all stress distributions on the membrane surface based on fiber grating sensing proposed in the present invention, its combination scheme includes multiple sets of membrane components fixed with multiple fiber grating sensors, and the membrane components are all hollow fiber membranes or flat plates film or rolled film; in each set of film components fixed with multiple fiber grating sensors, the position and connection relationship between the multiple fiber grating sensors and the film component is that the multiple fiber grating sensors are arranged according to the The direction of the water flow when the membrane module is working is distributed and arranged within the range of the corridor area, the distance between multiple fiber grating sensors and the membrane surface of the membrane module is 0-1mm; the grating wavelengths of the fiber grating sensors do not overlap each other; Multiple fiber grating sensors are connected in series with single-mode optical fibers to form a set of membrane components fixed with multiple fiber grating sensors; the two free ends of the fiber gratings of each set of membrane components fixed with multiple fiber grating sensors are single-mode Optical fiber connection, the connection mode is series or parallel or series-parallel; one end of the fiber grating in the membrane module fixed with multiple fiber grating sensors is connected to the input end of a fiber grating demodulator through a single-mode fiber Connect; the output end of the fiber grating demodulator is connected to a computer, and a data acquisition module and a data processing module are installed in the computer, and the data acquisition module adopts a matching device with the fiber grating sensor demodulator Software; the data processing module obtains the distribution of all stresses on the membrane surface of the membrane module through the collected changes in the grating wavelengths of the above-mentioned multiple fiber grating sensors according to the sensing principle of the fiber grating.
进一步讲，本发明中，所述光纤光栅传感器的带宽为0.2nm、反射率高于90％、栅区长度为10mm且加涂覆、光纤光栅传感器的中心波长范围为1530nm-1570nm，所述光纤光栅传感器的中心波长仅受温度和应变的影响。Further speaking, in the present invention, the bandwidth of the fiber grating sensor is 0.2nm, the reflectivity is higher than 90%, the gate length is 10mm and coated, and the center wavelength range of the fiber grating sensor is 1530nm-1570nm. The center wavelength of grating sensors is only affected by temperature and strain.
所述膜组件是超滤膜、中空纤维膜、正渗透膜组件和反渗透膜组件的任何一种。The membrane module is any one of ultrafiltration membrane, hollow fiber membrane, forward osmosis membrane module and reverse osmosis membrane module.
所述光纤光栅解调仪采用动态光纤光栅解调仪。The fiber grating demodulator adopts a dynamic fiber grating demodulator.
所述数据采集模块采用与动态光纤光栅解调仪配套的软件，所述数据采集模块设置的数据采集频率为每秒采集1-1000个数据。The data acquisition module adopts software matched with the dynamic fiber grating demodulator, and the data acquisition frequency set by the data acquisition module is 1-1000 data per second.
所述正渗透膜组件是板式正渗透膜组件，所述板式正渗透膜组件包括原料液侧盖板、汲取液侧盖板和FO膜，所述原料液侧盖板内侧设有原料液凹槽、原料液垫片、原料液进水口和原料液出水口，所述汲取液侧盖板内侧设有汲取液凹槽、汲取液垫片、汲取液进水口和汲取液出水口；所述多个光纤光栅传感器与所述膜组件相互之间的位置和连接关系是，多个光纤光栅传感器按照沿膜组件工作时的水流方向分布布置在所述原料液侧盖板内侧面或所述汲取液侧盖板内侧面，对每个光纤光栅传感器均施加预应力后并与所述FO膜的膜面之间的距离在0-1mm，所述原料液侧盖板或汲取液侧盖板与所述光纤光栅传感器之间用UV胶固定；将所述原料液侧盖板和所述汲取液侧盖板扣合后用螺栓连接件固定，从而使多个光纤光栅传感器与所述正渗透组件固定。The forward osmosis membrane module is a plate-type forward osmosis membrane module, and the plate-type forward osmosis membrane module includes a raw material liquid side cover plate, a draw liquid side cover plate and an FO membrane, and a raw material liquid groove is arranged inside the raw material liquid side cover plate , a raw material liquid gasket, a raw material liquid water inlet and a raw material liquid water outlet, the inside of the side cover plate of the drawn liquid is provided with a drawn liquid groove, a drawn liquid gasket, a drawn liquid water inlet and a drawn liquid outlet; the plurality of The position and connection relationship between the fiber grating sensor and the membrane module is that a plurality of fiber grating sensors are arranged on the inner side of the raw material liquid side cover plate or the draw liquid side according to the distribution along the water flow direction when the membrane module is working. The inner surface of the cover plate, after applying prestress to each fiber grating sensor and the distance between the membrane surface of the FO membrane is 0-1mm, the raw material liquid side cover plate or the draw liquid side cover plate and the The fiber grating sensors are fixed with UV glue; the raw material liquid side cover plate and the drawing liquid side cover plate are fastened and then fixed with bolt connectors, so that multiple fiber grating sensors are fixed with the forward osmosis component.
所述光纤光栅传感器的个数为6个，相邻光纤光栅传感器的光栅之间的相距为1cm，相邻光纤光栅传感器的光栅波长相差2～3nm。6个光纤光栅传感器的光栅波长分别为1556nm、1553nm、1550nm、1548nm、1546nm、1544nm。The number of the fiber grating sensors is 6, the distance between gratings of adjacent fiber grating sensors is 1 cm, and the grating wavelength difference of adjacent fiber grating sensors is 2-3 nm. The grating wavelengths of the six fiber grating sensors are 1556nm, 1553nm, 1550nm, 1548nm, 1546nm, and 1544nm.
本发明中还提出了基于光纤光栅传感的膜面所有应力分布测量方法，利用上述基于光纤光栅传感的膜面所有应力分布测量装置，步骤如下：The present invention also proposes a method for measuring all stress distributions on the film surface based on fiber grating sensing, using the above-mentioned measuring device for all stress distributions on the film surface based on fiber grating sensing, the steps are as follows:
步骤一、选择多根光纤光栅传感器，且其中任何两个光纤光栅传感器的中心波长相差不小于2nm，将多根光纤光栅传感器用单模光纤串联，对串联后的光纤光栅传感器施加预应力后使用UV胶固定在膜组件上，使每个光纤光栅传感器与膜面之间的距离在0-1mm；将膜组件封装后与所述光纤光栅解调仪连接，利用所述光纤光栅解调仪自带的软件测得各光纤光栅传感器的中心波长的静态值；Step 1. Select multiple fiber Bragg grating sensors, and the difference between the center wavelengths of any two fiber Bragg grating sensors is not less than 2nm, connect multiple fiber Bragg grating sensors in series with single-mode optical fibers, and apply prestress to the series fiber Bragg grating sensors before use UV glue is fixed on the membrane assembly, so that the distance between each fiber grating sensor and the membrane surface is 0-1mm; after the membrane assembly is packaged, it is connected to the fiber grating demodulator, and the fiber grating demodulator is used to automatically The software with the belt measures the static value of the center wavelength of each fiber grating sensor;
步骤二、将一水泵的出水口与膜组件的入水口相连，利用该水泵向膜组件的入水口注水，设定流速大于0且小于0.5m/s，在该流速范围内自小到大选定多个流速，按照选定的多个流速循环进行步骤三和步骤四的过程，直至完成多个流速下的数据采集后执行步骤五；Step 2. Connect the water outlet of a water pump to the water inlet of the membrane module, use the water pump to inject water into the water inlet of the membrane module, and set the flow rate to be greater than 0 and less than 0.5m/s, within the flow rate range from small to large Set multiple flow rates, and perform the process of step 3 and step 4 according to the selected multiple flow rates, until the data acquisition at multiple flow rates is completed and step 5 is executed;
步骤三、数据采集模块以每秒采集1-1000个数据的采集频率采集每个光纤光栅传感的中心波长，光纤光栅传感解调仪对采集到的波长信号解调后，所述光纤光栅解调仪自带的软件在注水过程中实时获得各光纤光栅传感器的中心波长的测量值；Step 3: The data acquisition module collects the center wavelength of each FBG sensor at a collection frequency of 1-1000 data per second, and after the FBG sensor demodulator demodulates the collected wavelength signal, the FBG The software that comes with the demodulator obtains the measured value of the central wavelength of each fiber grating sensor in real time during the water injection process;
步骤四、将步骤三获得的测量值减去步骤一获得的静态值，得到各个光纤光栅传感器在每一时刻的中心波长的变化值；求取采集时段内所得的各个光纤光栅传感器在每一时刻的中心波长的变化值的平均值，将该平均值作为该时段内每个光纤光栅传感器的中心波长的变化值；Step 4, subtract the static value obtained in step 1 from the measured value obtained in step 3 to obtain the change value of the center wavelength of each fiber grating sensor at each moment; The average value of the change value of the center wavelength of the fiber grating sensor, the average value is used as the change value of the center wavelength of each fiber grating sensor in this period;
步骤五、使用作图软件，以光纤光栅传感器距离膜组件入水口的距离为横坐标，以步骤四获得的采集时段内每个光纤光栅传感器的中心波长的变化值为纵坐标，绘制出采集时段内不同流速下各个光纤光栅传感器的中心波长变化分布图；Step 5. Using the drawing software, take the distance between the FBG sensor and the water inlet of the membrane module as the abscissa, and use the change value of the center wavelength of each FBG sensor in the collection period obtained in step 4 as the ordinate to draw the collection period The distribution diagram of the central wavelength change of each fiber grating sensor at different flow rates in the interior;
步骤六、利用步骤五获得的采集时段内不同流速下各个光纤光栅传感器的中心波长变化值，根据光线光栅的传感原理得到不同流速情况下膜面所受应力的分布情况。Step 6. Using the change values of the center wavelength of each FBG sensor at different flow rates within the collection period obtained in step 5, the distribution of the stress on the membrane surface under different flow rates is obtained according to the sensing principle of the FBG.
与现有技术相比，本发明的有益效果是：Compared with prior art, the beneficial effect of the present invention is:
本发明是利用光纤光栅传感器作为传感基元，采用波分复用的方法，将多根光纤光栅串联后置于板式正渗透膜组件内，使其与膜面接触，用于对膜的微界面研究中，进行分布测量，对膜面不同位置所受的应力进行分析。基于光纤的这种膜面所受应力的分析方法，解决微界面、小空间无法有效实时反馈膜面所受应力情况的问题。并通过光纤光栅解调仪对测量的信号进行解调，将信号转化成光栅中心波长的变化，进而分析处理，构成基于光纤光栅传感技术的膜面应力分布测量系统。The present invention uses the fiber grating sensor as the sensing element, adopts the method of wavelength division multiplexing, puts a plurality of fiber gratings in series and places them in the plate type forward osmosis membrane module, makes it contact with the membrane surface, and is used for micronization of the membrane. In the interface research, the distribution measurement is carried out to analyze the stress on different positions of the membrane surface. The analysis method of the stress on the membrane surface based on optical fiber solves the problem that micro-interfaces and small spaces cannot effectively feedback the stress on the membrane surface in real time. The measured signal is demodulated by the fiber grating demodulator, and the signal is converted into the change of the central wavelength of the grating, and then analyzed and processed to form a film surface stress distribution measurement system based on fiber grating sensing technology.
附图说明Description of drawings
图1是本发明基于光纤光栅传感的膜面所受应力分布测量装置的框图；Fig. 1 is the block diagram of the present invention based on the suffered stress distribution measuring device of the film surface of fiber grating sensing;
图2是本发明基于光纤光栅传感的膜面所受应力分布测量装置一实施例的主视剖视图；Fig. 2 is the front cross-sectional view of an embodiment of the device for measuring the stress distribution on the film surface based on fiber grating sensing in the present invention;
图3是图2所示测量装置的俯视图；Fig. 3 is the top view of measuring device shown in Fig. 2;
图4是本发明测量方法一实施例得出的光纤光栅传感器的中心波长变化分布图。Fig. 4 is a distribution diagram of the center wavelength variation of the fiber grating sensor obtained by an embodiment of the measurement method of the present invention.
具体实施方式Detailed ways
下面结合附图和具体实施例对本发明技术方案作进一步详细描述，所描述的具体实施例仅对本发明进行解释说明，并不用以限制本发明。The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the described specific embodiments are only for explaining the present invention, and are not intended to limit the present invention.
本发明的设计思路是，基于光纤光栅的特点和光纤光栅传感原理，将光纤光栅置于膜组件内，用于对膜的微界面研究中，进行分布测量，对膜面不同位置所受的应力进行分析。基于光纤的这种膜面所受应力的分析方法，解决微界面、小空间无法有效实时反馈膜面所受应力情况的问题。The design idea of the present invention is that, based on the characteristics of the fiber grating and the sensing principle of the fiber grating, the fiber grating is placed in the membrane assembly, and used for the distribution measurement of the micro-interface of the membrane. stress analysis. The analysis method of the stress on the membrane surface based on optical fiber solves the problem that micro-interfaces and small spaces cannot effectively feedback the stress on the membrane surface in real time.
本发明提出的一种基于光纤光栅传感的膜面所受应力分布测量装置，如图1所示，包括膜组件、光纤光栅传感器、光纤光栅解调仪、数据采集模块和数据处理模块，所述的数据采集模块和数据处理模块安装在一计算机中。多个光纤光栅传感器固定在膜组件内，所述多个光纤光栅传感器与所述膜组件相互之间的位置和连接关系是，多个光纤光栅传感器按照沿膜组件工作时的水流方向且在廊道区域范围内分布布置，多个光纤光栅传感器与所述膜组件的膜面之间的距离在0-1mm；相邻光纤光栅传感器的光栅之间的距离不受限制，各光纤光栅传感器的光栅波长互不重叠；多个光纤光栅传感器依次用单模光纤串联；串联后的光纤光栅传感器的一端为自由端，串联后的光纤光栅传感器的另一端通过单模光纤与一光纤光栅解调仪的输入端相连接；所述光纤光栅解调仪的输出端连接至一台计算机，所述计算机内安装有数据采集模块及数据处理模块，所述数据采集模块采用与所述光纤光栅传感解调仪配套的软件；所述数据处理模块根据光纤光栅的传感原理通过采集到的上述多个光纤光栅传感器的光栅波长的变化得出所述膜组件膜面所受应力的分布。A device for measuring stress distribution on a film surface based on fiber grating sensing proposed by the present invention, as shown in Figure 1, includes a film assembly, a fiber grating sensor, a fiber grating demodulator, a data acquisition module and a data processing module. The above data collection module and data processing module are installed in a computer. A plurality of fiber grating sensors are fixed in the membrane assembly, and the position and connection relationship between the plurality of fiber grating sensors and the membrane assembly is that the plurality of fiber grating sensors are arranged along the water flow direction of the membrane assembly and in the gallery The distance between multiple fiber grating sensors and the membrane surface of the membrane module is 0-1mm; the distance between the gratings of adjacent fiber grating sensors is not limited, and the gratings of each fiber grating sensor The wavelengths do not overlap each other; multiple fiber grating sensors are connected in series with single-mode fiber; one end of the fiber grating sensor after series is a free end, and the other end of the fiber grating sensor after series is connected to a fiber grating demodulator through a single-mode fiber The input end is connected; the output end of the fiber grating demodulator is connected to a computer, and a data acquisition module and a data processing module are installed in the computer, and the data acquisition module is demodulated with the fiber grating sensor The supporting software of the instrument; the data processing module obtains the distribution of the stress on the membrane surface of the membrane module through the collected changes of the grating wavelengths of the above-mentioned multiple fiber grating sensors according to the sensing principle of the fiber grating.
本发明中，膜组件均为中空纤维膜或是平板膜或是卷式膜；按孔径为可以是微滤、超滤、纳滤、反渗透和正渗透膜组件的任何一种。如图2和图3所示，以膜组件为板式正渗透膜组件为例，所述板式正渗透膜组件包括原料液侧盖板12、汲取液侧盖板22和FO膜3，所述原料液侧盖板10内侧设有原料液凹槽11、原料液垫片12、原料液进水口13和原料液出水口14，所述汲取液侧盖板20内侧设有汲取液凹槽21、汲取液垫片22、汲取液进水口23和汲取液出水口24；以将6个光纤光栅传感器固定在原料液侧盖板10内侧面为例，所述6个光纤光栅传感器与所述膜组件相互之间的位置和连接关系是，6个光纤光栅传感器按照沿膜组件工作时的水流方向分布布置在所述原料液侧盖板10内侧面，所述光纤光栅传感器4的带宽为0.2nm、反射率高于90％、栅区长度为10mm且加涂覆、光栅波长范围为1530nm-1570nm，所述光纤光栅传感器4的中心波长仅受温度和应变的影响。相邻光纤光栅传感器3的光栅之间的相距为1cm，相邻光纤光栅传感器4的光栅波长相差2～3nm，6个光纤光栅传感器3的光栅波长分别为1556nm、1553nm、1550nm、1548nm、1546nm、1544nm。对每个光纤光栅传感器均施加预应力后并与所述FO膜3的膜面之间的距离在0-1mm，所述原料液侧盖板10或汲取液侧盖板20与所述光纤光栅传感器之间用UV胶5固定；将所述原料液侧盖板10和所述汲取液侧盖板20扣合后用螺栓连接件6固定，从而使6个光纤光栅传感器4与所述正渗透组件固定。6个光纤光栅传感器依次用单模光纤串联；串联后的光纤光栅传感器的一端为自由端，串联后的光纤光栅传感器的另一端通过单模光纤与一光纤光栅解调仪的输入端相连接；所述光纤光栅解调仪的输出端连接至一台计算机，所述计算机内安装有数据采集模块及数据处理模块。In the present invention, the membrane modules are all hollow fiber membranes or flat membranes or rolled membranes; according to the pore size, they can be any one of microfiltration, ultrafiltration, nanofiltration, reverse osmosis and forward osmosis membrane modules. As shown in Figure 2 and Figure 3, taking the membrane module as an example of a plate-type forward osmosis membrane module, the plate-type forward osmosis membrane module includes a raw material liquid side cover plate 12, a draw liquid side cover plate 22 and an FO membrane 3, and the raw material The inner side of the liquid side cover plate 10 is provided with a raw material liquid groove 11, a raw material liquid gasket 12, a raw material liquid water inlet 13 and a raw material liquid water outlet 14. Liquid gasket 22, drawing liquid inlet 23 and drawing liquid outlet 24; taking 6 fiber grating sensors fixed on the inner surface of the raw material liquid side cover plate 10 as an example, the 6 fiber grating sensors and the membrane assembly are mutually The position and connection relationship among them is that 6 fiber grating sensors are arranged on the inner side of the raw material liquid side cover plate 10 according to the distribution along the water flow direction when the membrane module is working, and the bandwidth of the fiber grating sensor 4 is 0.2nm, reflection The ratio is higher than 90%, the length of the grating area is 10mm and coated, and the wavelength range of the grating is 1530nm-1570nm. The central wavelength of the fiber grating sensor 4 is only affected by temperature and strain. The distance between the gratings of adjacent fiber grating sensors 3 is 1 cm, and the grating wavelengths of adjacent fiber grating sensors 4 differ by 2 to 3 nm. 1544nm. After each fiber grating sensor is prestressed and the distance from the film surface of the FO membrane 3 is 0-1mm, the raw material liquid side cover plate 10 or the draw liquid side cover plate 20 is connected to the fiber grating sensor The sensors are fixed with UV glue 5; the raw material liquid side cover plate 10 and the drawing liquid side cover plate 20 are fastened and fixed with bolt connectors 6, so that the 6 fiber grating sensors 4 are connected to the forward osmosis Components are fixed. Six fiber grating sensors are connected in series with single-mode optical fibers in sequence; one end of the series-connected fiber grating sensors is a free end, and the other end of the series-connected fiber grating sensors is connected to the input end of a fiber grating demodulator through a single-mode fiber; The output end of the fiber grating demodulator is connected to a computer, and a data acquisition module and a data processing module are installed in the computer.
本发明中，所述光纤光栅解调仪7采用美国Micron Optics公司生产型号为SM130的动态光纤光栅传感解调仪，所述数据采集模块采用与美国Micron Optics公司的且与型号为SM130的动态光纤光栅解调仪配套的软件，所述数据采集模块设置的数据采集频率为每秒采集1-1000个数据。所述数据处理模块根据光纤光栅的传感原理通过采集到的上述6个光纤光栅传感器的光栅波长的变化得出所述膜组件膜面所受应力的分布。In the present invention, the fiber grating demodulator 7 adopts the dynamic fiber grating sensor demodulator produced by Micron Optics Company of the United States as SM130, and the data acquisition module adopts the dynamic sensor demodulator of SM130 produced by Micron Optics Company of the United States. The supporting software of the fiber grating demodulator, the data acquisition frequency set by the data acquisition module is 1-1000 data per second. The data processing module obtains the distribution of the stress on the membrane surface of the membrane module through the collected changes of the grating wavelengths of the six fiber grating sensors according to the sensing principle of the fiber grating.
本发明中，还可以是将多套固定有多个光纤光栅传感器的膜组件连接起来形成检测阵列，即一种基于光纤光栅传感的膜面所受应力分布测量装置，包括多套固定有多个光纤光栅传感器的膜组件，膜组件均为中空纤维膜或是平板膜或是卷式膜；按其孔径为可以是微滤、超滤、纳滤、反渗透和正渗透膜组件中的同一种；每套固定有多个光纤光栅传感器的膜组件中，所述多个光纤光栅传感器与所述膜组件相互之间的位置和连接关系是，多个光纤光栅传感器按照沿膜组件工作时的水流方向且在廊道区域范围内分布布置，多个光纤光栅传感器与所述膜组件的膜面之间的距离在0-1mm；相邻光纤光栅传感器的光栅之间的距离不受限制，各光纤光栅传感器的光栅波长互不重叠；多个光纤光栅传感器依次用单模光纤串联，从而形成一套固定有多个光纤光栅传感器的膜组件；将各套固定有多个光纤光栅传感器的膜组件的光纤光栅的两自由端用单模光纤连接，连接方式是串联或并联或串并联；将连接后的多套固定有多个光纤光栅传感器的膜组件中的光纤光栅的一端通过单模光纤与一光纤光栅解调仪的输入端相连接；所述光纤光栅解调仪的输出端连接至一台计算机，所述计算机内安装有数据采集模块及数据处理模块，所述数据采集模块采用与所述光纤光栅传感解调仪配套的软件；所述数据处理模块根据光纤光栅的传感原理通过采集到的上述多个光纤光栅传感器的光栅波长的变化得出所述膜组件膜面所受应力的分布。In the present invention, it is also possible to connect multiple sets of film components fixed with multiple fiber grating sensors to form a detection array, that is, a device for measuring the stress distribution on the film surface based on fiber grating sensing, including multiple sets of fixed The membrane components of a fiber grating sensor, the membrane components are hollow fiber membranes or flat membranes or roll membranes; according to their pore diameters, they can be the same type of membrane components in microfiltration, ultrafiltration, nanofiltration, reverse osmosis and forward osmosis ; In each set of membrane components fixed with a plurality of fiber grating sensors, the position and connection relationship between the plurality of fiber grating sensors and the membrane components is that a plurality of fiber grating sensors are in accordance with the water flow when working along the membrane components The distance between multiple fiber grating sensors and the membrane surface of the membrane module is 0-1mm; the distance between the gratings of adjacent fiber grating sensors is not limited, each optical fiber The grating wavelengths of the grating sensor do not overlap each other; multiple fiber grating sensors are connected in series with single-mode optical fibers to form a set of membrane components fixed with multiple fiber grating sensors; each set of membrane components fixed with multiple fiber grating sensors The two free ends of the fiber grating are connected with a single-mode fiber, and the connection mode is series or parallel or series-parallel; one end of the fiber grating in the membrane assembly fixed with a plurality of fiber grating sensors is connected to a single-mode fiber through a single-mode fiber. The input end of the fiber grating demodulator is connected; the output end of the fiber grating demodulator is connected to a computer, and a data acquisition module and a data processing module are installed in the computer, and the data acquisition module adopts the same method as described The supporting software of the fiber grating sensor demodulator; the data processing module obtains the stress on the membrane surface of the membrane module through the changes of the grating wavelengths of the above-mentioned multiple fiber grating sensors collected according to the sensing principle of the fiber grating distributed.
利用上述基于光纤光栅传感的膜面所受应力分布测量装置进行测量的步骤如下：The steps of using the above-mentioned stress distribution measurement device based on fiber grating sensing to measure the film surface are as follows:
步骤一、选择多根光纤光栅传感器，且其中任何两个光纤光栅传感器的中心波长相差不小于2nm，将多根光纤光栅传感器用单模光纤串联，对串联后的光纤光栅传感器施加预应力后使用UV胶固定在膜组件上，多个光纤光栅传感器与所述膜组件的膜面之间的距离在0-1mm；将膜组件封装后与所述光纤光栅解调仪连接，利用所述光纤光栅解调仪自带的软件测得各光纤光栅传感器的中心波长的静态值；Step 1. Select multiple fiber Bragg grating sensors, and the difference between the center wavelengths of any two fiber Bragg grating sensors is not less than 2nm, connect multiple fiber Bragg grating sensors in series with single-mode optical fibers, and apply prestress to the series fiber Bragg grating sensors before use The UV glue is fixed on the membrane assembly, and the distance between a plurality of fiber grating sensors and the membrane surface of the membrane assembly is 0-1mm; after the membrane assembly is packaged, it is connected to the fiber grating demodulator, and the fiber grating The software that comes with the demodulator measures the static value of the center wavelength of each fiber grating sensor;
本实施例中，将6根光纤光栅传感器串联，使用UV胶分布固定在膜组件上，使其与膜面紧密接触，光纤光栅传感器与膜面之间也可以具有小于1mm的距离。相邻光纤光栅传感器之间的相距为1cm，各光纤光栅传感器的中心波长相差不小于2nm。6个光纤光栅传感器的中心波长的基准值分别为1537.88nm、1539.89nm、1542.09nm、1547.94nm、1550.25nm、1559.23nm。光纤光栅中心波长按照距离膜组件入水口距离H由近到远依次为：1cm处为1559.23nm、2cm处为1550.25nm、3cm处为1547.94nm、4cm处为1537.88nm、5cm处为1539.89nm、6cm处为1542.09nm。In this embodiment, six fiber grating sensors are connected in series and fixed on the membrane assembly with UV glue so that they are in close contact with the membrane surface. The distance between the fiber grating sensor and the membrane surface may also be less than 1mm. The distance between adjacent fiber grating sensors is 1 cm, and the center wavelength difference of each fiber grating sensor is not less than 2 nm. The reference values of the center wavelengths of the six fiber grating sensors are 1537.88nm, 1539.89nm, 1542.09nm, 1547.94nm, 1550.25nm, and 1559.23nm, respectively. The central wavelength of the fiber grating according to the distance H from the water inlet of the membrane module from near to far: 1559.23nm at 1cm, 1550.25nm at 2cm, 1547.94nm at 3cm, 1537.88nm at 4cm, 1539.89nm at 5cm, 6cm at 1542.09nm.
特别强调的是，本发明中在放置光纤光栅传感器时，对于光纤光栅传感器之间的距离没有限制，通常采用在膜面上沿水流方向均布即可，多个光纤光栅传感器的排放位置，也可不用按照中心波长依次由大到小进行放置，只要是所有的光纤光栅传感器中任何两个的中心波长相差不小于2nm即可。It is particularly emphasized that in the present invention, when placing the fiber grating sensors, there is no limit to the distance between the fiber grating sensors, and it is usually uniformly distributed along the water flow direction on the membrane surface, and the discharge positions of multiple fiber grating sensors can also be It is not necessary to place them according to the central wavelength from large to small, as long as the difference between the central wavelengths of any two fiber grating sensors is not less than 2nm.
串联后的光纤光栅传感器两端中的任一端为自由端，另一端则通过单模光纤与一光纤光栅解调仪的输入端相连接，光纤光栅解调仪使用由美国Micron Optics公司生产型号为SM130的动态光纤光栅传感解调仪。光纤光栅解调仪的输出端连接至一台计算机，计算机内安装有数据采集模块及数据处理模块，采用美国Micron Optics公司生产型号为SM130的动态光纤光栅传感解调仪配套的软件。将膜组件封装后，测得各光纤光栅中心波长的静态值分别为1cm处为1559.37nm、2cm处为1550.46nm、3cm处为1548.09nm、4cm处为1538.16nm、5cm处为1540.20nm、6cm处为1542.40nm。Either end of the two ends of the fiber grating sensor connected in series is a free end, and the other end is connected to the input end of a fiber grating demodulator through a single-mode fiber. The fiber grating demodulator uses a model produced by Micron Optics of the United States SM130 dynamic fiber grating sensor demodulator. The output end of the fiber grating demodulator is connected to a computer, which is equipped with a data acquisition module and a data processing module, and adopts the supporting software of the dynamic fiber grating sensor demodulator model SM130 produced by Micron Optics of the United States. After the membrane module is packaged, the measured static values of the central wavelength of each fiber grating are 1559.37nm at 1cm, 1550.46nm at 2cm, 1548.09nm at 3cm, 1538.16nm at 4cm, 1540.20nm at 5cm, and 1540.20nm at 6cm. 1542.40nm.
步骤二、将一水泵的出水口与膜组件的入水口相连，利用该水泵向膜组件的入水口注水，设定流速大于0且小于0.5m/s，在该流速范围内自小到大选定多个流速，按照选定的多个流速循环进行步骤三和步骤四的过程，直至完成多个流速下的数据采集后执行步骤五；Step 2. Connect the water outlet of a water pump to the water inlet of the membrane module, use the water pump to inject water into the water inlet of the membrane module, and set the flow rate to be greater than 0 and less than 0.5m/s, within the flow rate range from small to large Set multiple flow rates, and perform the process of step 3 and step 4 according to the selected multiple flow rates, until the data acquisition at multiple flow rates is completed and step 5 is executed;
本实施例中，设定4个流速分别为0.16m/s、0.24m/s、0.32m/s和0.40m/s。In this embodiment, four flow velocities are set to be 0.16m/s, 0.24m/s, 0.32m/s and 0.40m/s respectively.
步骤三、数据采集模块以每秒采集一个数据的采集频率采集每个光纤光栅传感的中心波长，光纤光栅传感解调仪对采集到的波长信号解调后，所述光纤光栅解调仪自带的软件实时测得注水过程中间隔为1秒的每一时刻各光纤光栅传感器的中心波长的测量值。Step 3: The data acquisition module collects the central wavelength of each fiber grating sensor at a frequency of collecting one data per second, and after the fiber grating sensor demodulator demodulates the collected wavelength signal, the fiber grating demodulator The built-in software measures the measured value of the central wavelength of each fiber grating sensor at each moment during the water injection process with an interval of 1 second in real time.
步骤四、将步骤三获得的静态值减去步骤一获得的测量值，得到各个光纤光栅传感器间隔为1秒的每一时刻各光纤光栅传感器的中心波长的测量值；求取采集时段内所得的各个光纤光栅传感器间隔为1秒的每一时刻各光纤光栅传感器的中心波长的测量值的中心波长的变化值的平均值，将该平均值作为该时段内每个光纤光栅传感器的中心波长的变化值；Step 4, subtract the measured value obtained in step 1 from the static value obtained in step 3 to obtain the measured value of the center wavelength of each fiber grating sensor at each moment when the interval of each fiber grating sensor is 1 second; The average value of the change value of the center wavelength of the measured value of the center wavelength of each fiber Bragg grating sensor at each moment when the interval of each fiber Bragg grating sensor is 1 second, the average value is used as the change of the center wavelength of each fiber Bragg grating sensor in this period value;
本实施例中，水泵在膜组件的入水口通入水流，设置入水口的水流流速为0.16m/s。其位于膜面不同位置的光纤光栅传感器将由于水流冲刷作用产生的应力信号转换成光纤光栅中心波长变化的波长信号。光纤光栅传感器感知到的波长信号通过本实施例中采用的美国Micron Optics公司生产型号为SM130的动态光纤光栅传感解调仪进行解调，光纤光栅动态解调仪通过以太网将获取的波长变化数据输送到由美国Micron Optics公司生产型号为SM130的动态光纤光栅传感解调仪配套的软件进行数据采集，数据采集模块以每秒采集一个数据的采集频率对光纤光栅的中心波长随时间的变化进行采集，获得光纤光栅波长随时间的变化的测量值，1cm处为1559.58nm、1550.82nm、1548.46nm、1538.63nm、1540.51nm、1542.62nm。In this embodiment, the water pump feeds water into the water inlet of the membrane module, and the water flow velocity at the water inlet is set to 0.16m/s. The fiber grating sensors located at different positions on the membrane surface convert the stress signal generated by the water flow into the wavelength signal of the center wavelength change of the fiber grating. The wavelength signal sensed by the fiber grating sensor is demodulated by the SM130 dynamic fiber grating sensor demodulator produced by the Micron Optics company in the United States used in this embodiment, and the fiber grating dynamic demodulator changes the acquired wavelength through Ethernet The data is sent to the supporting software of the SM130 dynamic fiber grating sensor demodulator produced by Micron Optics in the United States for data collection. Collect and obtain the measured value of the fiber grating wavelength change with time, 1559.58nm, 1550.82nm, 1548.46nm, 1538.63nm, 1540.51nm, 1542.62nm at 1cm.
上述4个流速0.16m/s、0.24m/s、0.32m/s和0.40m/s情况下的基准值相同，但每种入口流速均测量对应的静态值和测量值，所测得的静态值的数值均大于基准值，有关数据参见表1至表5。The above four flow rates of 0.16m/s, 0.24m/s, 0.32m/s and 0.40m/s have the same reference value, but each inlet flow rate measures the corresponding static value and measured value, and the measured static The numerical values of the values are all greater than the benchmark values, see Table 1 to Table 5 for relevant data.
表1.流速为0.16m/s时6个光纤光栅传感器各中心波长的数值：Table 1. Values of each central wavelength of the 6 fiber grating sensors when the flow velocity is 0.16m/s:
表2.流速为0.24m/s时6个光纤光栅传感器各中心波长的数值：Table 2. Values of each central wavelength of the 6 fiber grating sensors when the flow velocity is 0.24m/s:
表3.流速为0.32m/s时6个光纤光栅传感器各中心波长的数值：Table 3. Values of each central wavelength of the 6 fiber grating sensors when the flow velocity is 0.32m/s:
表4.流速为0.40m/s时6个光纤光栅传感器各中心波长的数值：Table 4. Values of each central wavelength of the 6 fiber grating sensors when the flow velocity is 0.40m/s:
表5.得到不同流速下波长的变化值为：Table 5. The change value of the wavelength obtained at different flow rates is:
步骤五、使用作图软件，本实施例中，使用美国OriginLab公司开发的origin8.0作图软件，以光纤光栅传感器距离膜组件入水口的距离为横坐标，以步骤四获得的采集时段内每个光纤光栅传感器的中心波长的变化值为纵坐标，绘制出采集时段内不同流速下各个光纤光栅传感器的中心波长变化分布图，如图4所示。Step 5, use the drawing software, in the present embodiment, use the origin8.0 drawing software that U.S. OriginLab Company develops, take the distance of the fiber grating sensor from the water inlet of the membrane module as the abscissa, and use the acquisition period obtained in step 4 for each The change value of the central wavelength of each FBG sensor is the ordinate, and the distribution map of the central wavelength change of each FBG sensor at different flow rates within the acquisition period is drawn, as shown in Figure 4.
步骤六、利用步骤五获得的采集时段内不同流速下各个光纤光栅传感器的中心波长变化值，根据光线光栅的传感原理得到不同流速情况下膜面所受应力的分布情况，膜面不同位置处光纤光栅传感器中心波长的变化情况即为膜面应力的变化情况，最终得到不同入口流速情况下膜面不同位置所受应力的分布情况，从而为进一步对膜面水力学情况进行研究奠定了基础。其原理如下：Step 6. Use the center wavelength change values of each fiber grating sensor at different flow rates during the acquisition period obtained in step 5, and obtain the distribution of the stress on the membrane surface at different flow rates according to the sensing principle of the fiber grating. The change of the central wavelength of the fiber grating sensor is the change of the membrane surface stress, and finally the distribution of the stress at different positions on the membrane surface under different inlet flow rates is obtained, which lays the foundation for further research on the hydraulics of the membrane surface. The principle is as follows:
光纤光栅具有当外界温度或应变改变时，光纤纤芯的有效折射率和光纤光栅的周期都会发生改变，从而引起光纤光栅中心波长的改变，如式1：When the external temperature or strain changes, the effective refractive index of the fiber core and the period of the fiber grating will change, which will cause the change of the center wavelength of the fiber grating, as shown in formula 1:
ΔλB(αΔT+ξΔT)λB+(Δε-PcΔε)λB (1)Δλ B (αΔT+ξΔT)λ B +(Δε-P c Δε)λ B (1)
式(1)中：λB——光栅中心波长，单位为nm；ΔλB——光栅中心波长变化量，单位为nm；Pc为光纤光栅有效弹光系数；Δε为应变变化；ζ为光纤光栅材料热光系数；α为光纤光栅的热膨胀系数；ΔT为温度变化。In formula (1): λ B —— grating center wavelength, unit is nm; Δλ B —— grating center wavelength variation, unit is nm; P c is fiber grating effective elasto-optic coefficient; Δε is strain change; ζ is fiber The thermo-optic coefficient of the grating material; α is the thermal expansion coefficient of the fiber grating; ΔT is the temperature change.
当不考虑温度变化时，式1中ΔT＝0，光纤光栅受到均匀轴向应变所引起中心波长相对位移公式为式(2)：When the temperature change is not considered, ΔT=0 in formula 1, the relative displacement formula of the center wavelength caused by the fiber grating being subjected to uniform axial strain is formula (2):
ΔλB/λB＝(1-Pc)Δε (2) Δλ B/λ B =(1-P c )Δε (2)
式(2)中，Pc为光纤光栅有效弹光系数，可表示为式(3)：In formula (2), P c is the effective elasto-optic coefficient of the fiber grating, which can be expressed as formula (3):
式(3)中：μ为光纤材料的泊松比；P11、P12均为光纤的弹光系数；neff为光纤光栅的有效折射率。In formula (3): μ is the Poisson's ratio of the fiber material; P 11 and P 12 are the elasto-optic coefficients of the fiber; n eff is the effective refractive index of the fiber grating.
选用掺锗石英光纤，式(3)中各参数分别为neff＝1.46，μ＝0.16，P11＝0.12，P12＝0.27，由此可以计算出Pc＝0.22，The germanium-doped silica fiber is selected, and the parameters in formula (3) are n eff =1.46, μ=0.16, P 11 =0.12, P 12 =0.27, from which it can be calculated that P c =0.22,
将Pc＝0.22带入式(2)得式(4)Put P c =0.22 into formula (2) to get formula (4)
ΔλB/λB＝0.78Δε (4)Δλ B /λ B =0.78Δε (4)
应力引起光纤光栅波长的改变由应力产生的轴向应变来实现：The change of the wavelength of the fiber grating caused by stress is realized by the axial strain caused by the stress:
式(5)中E表示光纤的弹性模量，由材料固有性质决定，为定值；λB为光栅的中心波长，为定值。由此可以得到光栅中心波长变化ΔλB与应力的线性关系。In formula (5), E represents the elastic modulus of the optical fiber, which is determined by the inherent properties of the material and is a constant value; λ B is the central wavelength of the grating and is a constant value. From this, the linear relationship between the grating center wavelength change Δλ B and the stress can be obtained.
尽管上面结合附图对本发明进行了描述，但是本发明并不局限于上述的具体实施方式，上述的具体实施方式仅仅是示意性的，而不是限制性的，本领域的普通技术人员在本发明的启示下，在不脱离本发明宗旨的情况下，还可以做出很多变形，这些均属于本发明的保护之内。Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the enlightenment of the present invention, many modifications can be made without departing from the gist of the present invention, and these all belong to the protection of the present invention.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711188867.4A CN107966234B (en) | 2017-11-24 | 2017-11-24 | Apparatus and method for measuring stress distribution on membrane surface based on fiber grating sensing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711188867.4A CN107966234B (en) | 2017-11-24 | 2017-11-24 | Apparatus and method for measuring stress distribution on membrane surface based on fiber grating sensing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107966234A true CN107966234A (en) | 2018-04-27 |
| CN107966234B CN107966234B (en) | 2020-02-28 |
Family
ID=62000540
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711188867.4A Active CN107966234B (en) | 2017-11-24 | 2017-11-24 | Apparatus and method for measuring stress distribution on membrane surface based on fiber grating sensing |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107966234B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118310672A (en) * | 2024-06-07 | 2024-07-09 | 苏州南智传感科技有限公司 | Continuous osmotic pressure sensor and working method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7680363B2 (en) * | 2006-08-15 | 2010-03-16 | Suncall Corporation | Optical pressure sensor |
| CN201662451U (en) * | 2010-04-26 | 2010-12-01 | 同济大学 | A film surface tension measuring instrument |
| CN105157900A (en) * | 2015-08-31 | 2015-12-16 | 北京交通大学 | Measurement apparatus of prestress of membrane material |
| CN105352652A (en) * | 2015-09-30 | 2016-02-24 | 南京航空航天大学 | Difference fiber bragg grating baroceptor and method of monitoring airspeed tube dynamic pressure of airplane employing the same |
-
2017
- 2017-11-24 CN CN201711188867.4A patent/CN107966234B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7680363B2 (en) * | 2006-08-15 | 2010-03-16 | Suncall Corporation | Optical pressure sensor |
| CN201662451U (en) * | 2010-04-26 | 2010-12-01 | 同济大学 | A film surface tension measuring instrument |
| CN105157900A (en) * | 2015-08-31 | 2015-12-16 | 北京交通大学 | Measurement apparatus of prestress of membrane material |
| CN105352652A (en) * | 2015-09-30 | 2016-02-24 | 南京航空航天大学 | Difference fiber bragg grating baroceptor and method of monitoring airspeed tube dynamic pressure of airplane employing the same |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118310672A (en) * | 2024-06-07 | 2024-07-09 | 苏州南智传感科技有限公司 | Continuous osmotic pressure sensor and working method thereof |
| CN118310672B (en) * | 2024-06-07 | 2024-09-13 | 苏州南智传感科技有限公司 | Continuous osmotic pressure sensor and working method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107966234B (en) | 2020-02-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Friebele | Fiber Bragg grating strain sensors: present and future applications in smart structures | |
| Allwood et al. | A highly sensitive fiber Bragg grating diaphragm pressure transducer | |
| Hongo et al. | Applications of fiber Bragg grating sensors and high‐speed interrogation techniques | |
| CN110864742B (en) | All-fiber temperature and salt depth sensor based on micro-nano fiber coupler interferometer | |
| IL180258A0 (en) | Optical sensors | |
| CN102620858A (en) | Double long period fiber grating (LPFG) temperature and humidity sensor | |
| US9689714B2 (en) | Multiplexed fiber-coupled fabry-perot sensors and method therefor | |
| CN104316996A (en) | Waveguide Bragg grating refractive index sensor based on integrated polymers | |
| CN103277387A (en) | Intelligent bolt for optical fiber grating sensor | |
| WO2011123040A1 (en) | A parallel separation system | |
| CN107966234A (en) | Based on stress distribution measuring device and method suffered by the film surface of optical fiber grating sensing | |
| CN207540631U (en) | A kind of fiber grating Level monitor | |
| Shen et al. | Dual self-growing polymer microtips on a multicore fiber for humidity and temperature discriminative sensing | |
| CN102961970B (en) | Device for testing antifouling property of hollow-fibre membrane | |
| CN102680134A (en) | Dual-parameter measurement optical fiber grating sensor using chemical corrosion and chemical plating | |
| CN108759997A (en) | It is a kind of to be used for the optical fiber sensing system and its monitoring method that petrochemical industry feed belt is weighed | |
| CN110031139B (en) | A contact type linear stress sensor and its stress detection method | |
| CN200979435Y (en) | A data self-recording machine for a water meter | |
| CN214667319U (en) | Temperature monitoring device based on fiber bragg grating sensing | |
| CN113340457B (en) | Seawater surface temperature dense profile sensor based on FBG array | |
| CN109374028A (en) | A Distributed Multiplexing and Demodulation System Based on Cascaded Long Period Fiber Gratings | |
| Bai et al. | Hydraulics characteristics of forward osmosis membrane module boundary based on FBG sensing technology: Hydraulic properties and operating condition optimization | |
| Zhang et al. | Matched FBG application research on dynamic sensing and demodulation | |
| CN102135459B (en) | AWG (Array Waveguide Grating) differential demodulation based intensity detection type PCF-LPG (Long-Period Grating Written in a Photonic Crystal Fiber) stress sensor | |
| CN104655315A (en) | Prestrain fiber grating and sensor thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |