Based on the characteristic curve analysis, the method using D(K^2) square difference of meter factor at different flow rates was developed to evaluate the performance of turbine flow sensor in this study. Then accord...Based on the characteristic curve analysis, the method using D(K^2) square difference of meter factor at different flow rates was developed to evaluate the performance of turbine flow sensor in this study. Then according to the distribution of entrance velocity, it was supposed that reducing the blade area near the tip could decrease the linearity error of a sensor. Therefore, the influence of different blade shape parameters on the performance of the sensor was investigated by combining computational fluid dynamics(CFD)simulation with experimental test. The experimental results showed that, for the liquid turbine flow sensor with a diameter of 10 mm, the linearity error was smallest, and the performance of sensor was optimal when blade shape parameter equaled 0.25.展开更多
A passive simulation method based on the six degrees of freedom(6-DOF)model and dynamic mesh is proposed according to the working principle to study the dynamic characteristics of the turbine flow sensors.This simulat...A passive simulation method based on the six degrees of freedom(6-DOF)model and dynamic mesh is proposed according to the working principle to study the dynamic characteristics of the turbine flow sensors.This simulation method controls the six degrees of freedom of the impeller using the user-defined functions(UDF)program so that it can only rotate under the impact of fluid.The impeller speed can be calculated in real-time,and the inlet speed can be set with time to obtain the dynamic performance of the turbine flow sensors.Based on this simulation method,three turbine flow sensors with different diameters were simulated,and the reliability of the simulation method was verified by both steady-state and unsteady-state experiments.The results show that the trend of meter factor with flow rate acquired from the simulation is close to the experimental results.The deviation between the simulation and experiment results is low,with a maximum deviation of 2.88%.In the unsteady simulation study,the impeller speed changed with the inlet velocity of the turbine flow sensor,showing good tracking performance.The passive simulation method can be used to predict the dynamic performance of the turbine flow sensor.展开更多
A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperatur...A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed.The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s flow.However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/s.Thus,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.展开更多
Oil-gas-water three-phase flow in the pipe is commonly encountered in the petroleum and nature gas industry. Its flow patterns are complex and always changeable, so it’s difficult to be measured and is becoming one o...Oil-gas-water three-phase flow in the pipe is commonly encountered in the petroleum and nature gas industry. Its flow patterns are complex and always changeable, so it’s difficult to be measured and is becoming one of the most important subjects. Moreover, most of the oil fields in China are in such a high water fraction period that measures must be taken to meet the needs of the actual production. A conductance sensor which is widely used in the measurements of oil-water two-phase flow is used to measure the flow rate of the three-phase flow based on the research of the characteristics and the correlation theory, and a new technical solution which is suitable for measuring the oil-gas-water three-phase flow is established. A series of tests demonstrate that it’s feasible to use the conductance sensor in the measurements of oil- gas-water three-phase flow.展开更多
The signals generated by electromagnetic flow sensors used for slurry fluids are often affected by noise interference produced by interaction with the slurry itself.In this study,the power spectrum characteristics of...The signals generated by electromagnetic flow sensors used for slurry fluids are often affected by noise interference produced by interaction with the slurry itself.In this study,the power spectrum characteristics of the signal are studied,and an attempt is made to determine the relationship between the characteristics of the related noise and the velocity and concentration of the slurry fluid.Dedicated experiments are conducted and the related power spectrum curve is obtained processing the signal measured by the sensor with Matlab.Numerical simulations are also carried out in the frame of an Eulerian approach in order get additional insights into the considered problem through comparison with the experimental results.The following conclusions are drawn:(1)The intensity of noise is directly proportional to the number of solid particles colliding with the electrode of the electromagnetic flow sensor per unit time,and to the square of the average velocity of the flow layer near the pipe wall.(2)With an increase in the slurry noise intensity,the power spectrum curve shifts upward in the logarithmic coordinate system(and vice versa).展开更多
The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by princ...The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.展开更多
Computational Fluid Dynamics(CFD)simulation is one of the important methods to study the performance and influencing factors of turbine flow sensors.According to the working characteristics of the turbine flow sensor,...Computational Fluid Dynamics(CFD)simulation is one of the important methods to study the performance and influencing factors of turbine flow sensors.According to the working characteristics of the turbine flow sensor,the passive simulation method based on the six degrees of freedom(6-DOF)model and dynamic mesh is proposed in this paper.The reliability of the simulation method is verified by steady-state experiments and unsteady-state experiments.The results show that the trend of meter factor with flow rate acquired from the simulation is close to the experimental results,and the deviation between the simulation result and the experiment result is low with a maximum deviation of 2.88%.In the unsteady simulation study,the impeller speed changes with the inlet velocity of the turbine flow sensor,which has a good follow-up.The passive simulation method can be used to predict the dynamic performance of the turbine flow sensor.展开更多
Water outlets for washing hands and medical equipment are essential for preventing hospital infection. The present study clarified the effects of water flow volume on the identification and quantitative evaluation of ...Water outlets for washing hands and medical equipment are essential for preventing hospital infection. The present study clarified the effects of water flow volume on the identification and quantitative evaluation of bacteria found around spouts in the 17 hand-washing stations. Pseu-domonas aeruginosa was detected from 4 sta-tions before adjustment and 2 after adjustment. Although no significant difference was identified in the detection rate of P. aeruginosa (p = 0.368), when combining P. aeruginosa and glucose non-fermentative Gram-negative bacilli (NFB), the number of stations with P. aeruginosa and/or NFB decreased significantly from 15 before adjustment to 9 after adjustment (p = 0.023). Before adjust-ment, quantity of bacteria was “2+” for 3 stations and “1+” for 7 stations, but was “1+” for 3 stations and “2+” for 0 stations after adjustment. These results show that quantity of bacteria could be reduced from spouts by adjusting flow volume. These results were also supported by experiments for cleanliness using Adenosine 5’-triphosphate bioluminescence me- thod.展开更多
A novel chemiluminescence (CL) sensor for NH4+ combined with flow injection analysis is presented in this paper. It is based on the inhibition effect of NH4+ on the CL reaction between luminol, immobilized electrostat...A novel chemiluminescence (CL) sensor for NH4+ combined with flow injection analysis is presented in this paper. It is based on the inhibition effect of NH4+ on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and hypochlorous acid electrogenerated on-line. The sensor responds linearly to NH4+ concentration in 1.0x10(-6)-4.0x10(-9) g/ml range. A complete analysis could be performed in 1 min. The system is stable for 200 determination.展开更多
为减少联合收获机振动对谷物流量传感器监测结果的干扰,设计了一种基于声学黑洞(ABH,acoustic black hole)原理的谷物流量传感器龙门支架减振结构,通过有限元方法分析减振结构的振动特性,分析了二维声学黑洞比例系数ε、幂函数指数m和半...为减少联合收获机振动对谷物流量传感器监测结果的干扰,设计了一种基于声学黑洞(ABH,acoustic black hole)原理的谷物流量传感器龙门支架减振结构,通过有限元方法分析减振结构的振动特性,分析了二维声学黑洞比例系数ε、幂函数指数m和半径R对其减振性能的影响规律。结果表明,声学黑洞能够显著降低龙门支架的振动,ε、m和R对声学黑洞减振性能的影响均未表现出明显线性关系,当ε=0.001 2、m=2.5、R=15 mm时声学黑洞的减振效果最好。以振动速度平方和作为优化目标,建立了多项式回归代理模型,通过遗传算法对声学黑洞比例系数ε、幂函数指数m和半径R的取值进行了优化。相比于未添加声学黑洞的原始龙门支架和初始声学黑洞方案,优化后龙门支架的振动速度平方和分别降低68.92%和2%,表明优化方案具有更佳的减振性能。提出的基于声学黑洞的减振结构和优化设计方法为农业机械被动宽频减振研究提供了理论参考。展开更多
文摘Based on the characteristic curve analysis, the method using D(K^2) square difference of meter factor at different flow rates was developed to evaluate the performance of turbine flow sensor in this study. Then according to the distribution of entrance velocity, it was supposed that reducing the blade area near the tip could decrease the linearity error of a sensor. Therefore, the influence of different blade shape parameters on the performance of the sensor was investigated by combining computational fluid dynamics(CFD)simulation with experimental test. The experimental results showed that, for the liquid turbine flow sensor with a diameter of 10 mm, the linearity error was smallest, and the performance of sensor was optimal when blade shape parameter equaled 0.25.
基金The National Natural Science Foundation of China(No.62173122)the Hebei Key Project of Natural Science Foundation(No.F2021201031)。
文摘A passive simulation method based on the six degrees of freedom(6-DOF)model and dynamic mesh is proposed according to the working principle to study the dynamic characteristics of the turbine flow sensors.This simulation method controls the six degrees of freedom of the impeller using the user-defined functions(UDF)program so that it can only rotate under the impact of fluid.The impeller speed can be calculated in real-time,and the inlet speed can be set with time to obtain the dynamic performance of the turbine flow sensors.Based on this simulation method,three turbine flow sensors with different diameters were simulated,and the reliability of the simulation method was verified by both steady-state and unsteady-state experiments.The results show that the trend of meter factor with flow rate acquired from the simulation is close to the experimental results.The deviation between the simulation and experiment results is low,with a maximum deviation of 2.88%.In the unsteady simulation study,the impeller speed changed with the inlet velocity of the turbine flow sensor,showing good tracking performance.The passive simulation method can be used to predict the dynamic performance of the turbine flow sensor.
文摘A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed.The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s flow.However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/s.Thus,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.
文摘Oil-gas-water three-phase flow in the pipe is commonly encountered in the petroleum and nature gas industry. Its flow patterns are complex and always changeable, so it’s difficult to be measured and is becoming one of the most important subjects. Moreover, most of the oil fields in China are in such a high water fraction period that measures must be taken to meet the needs of the actual production. A conductance sensor which is widely used in the measurements of oil-water two-phase flow is used to measure the flow rate of the three-phase flow based on the research of the characteristics and the correlation theory, and a new technical solution which is suitable for measuring the oil-gas-water three-phase flow is established. A series of tests demonstrate that it’s feasible to use the conductance sensor in the measurements of oil- gas-water three-phase flow.
基金National Key Research and Development Program of China Subproject(No.2016YFD0700103)Natural Science Foundation of Henan(Nos.202300410124&19HASTIT021)+1 种基金Key Research and Development Program of Yunnan Province(No.2018ZC001)the National Natural Science foundation of China under Grant No.61801288.
文摘The signals generated by electromagnetic flow sensors used for slurry fluids are often affected by noise interference produced by interaction with the slurry itself.In this study,the power spectrum characteristics of the signal are studied,and an attempt is made to determine the relationship between the characteristics of the related noise and the velocity and concentration of the slurry fluid.Dedicated experiments are conducted and the related power spectrum curve is obtained processing the signal measured by the sensor with Matlab.Numerical simulations are also carried out in the frame of an Eulerian approach in order get additional insights into the considered problem through comparison with the experimental results.The following conclusions are drawn:(1)The intensity of noise is directly proportional to the number of solid particles colliding with the electrode of the electromagnetic flow sensor per unit time,and to the square of the average velocity of the flow layer near the pipe wall.(2)With an increase in the slurry noise intensity,the power spectrum curve shifts upward in the logarithmic coordinate system(and vice versa).
文摘The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.
基金supported by National Natural Science Foundation of China,China(62173122)Hebei Key Project of Natural Science Foundation(F2021201031)Beijing-Tianjin-Hebei Collaborative Innovation Community Construction Project(20540301D)
文摘Computational Fluid Dynamics(CFD)simulation is one of the important methods to study the performance and influencing factors of turbine flow sensors.According to the working characteristics of the turbine flow sensor,the passive simulation method based on the six degrees of freedom(6-DOF)model and dynamic mesh is proposed in this paper.The reliability of the simulation method is verified by steady-state experiments and unsteady-state experiments.The results show that the trend of meter factor with flow rate acquired from the simulation is close to the experimental results,and the deviation between the simulation result and the experiment result is low with a maximum deviation of 2.88%.In the unsteady simulation study,the impeller speed changes with the inlet velocity of the turbine flow sensor,which has a good follow-up.The passive simulation method can be used to predict the dynamic performance of the turbine flow sensor.
文摘Water outlets for washing hands and medical equipment are essential for preventing hospital infection. The present study clarified the effects of water flow volume on the identification and quantitative evaluation of bacteria found around spouts in the 17 hand-washing stations. Pseu-domonas aeruginosa was detected from 4 sta-tions before adjustment and 2 after adjustment. Although no significant difference was identified in the detection rate of P. aeruginosa (p = 0.368), when combining P. aeruginosa and glucose non-fermentative Gram-negative bacilli (NFB), the number of stations with P. aeruginosa and/or NFB decreased significantly from 15 before adjustment to 9 after adjustment (p = 0.023). Before adjust-ment, quantity of bacteria was “2+” for 3 stations and “1+” for 7 stations, but was “1+” for 3 stations and “2+” for 0 stations after adjustment. These results show that quantity of bacteria could be reduced from spouts by adjusting flow volume. These results were also supported by experiments for cleanliness using Adenosine 5’-triphosphate bioluminescence me- thod.
文摘A novel chemiluminescence (CL) sensor for NH4+ combined with flow injection analysis is presented in this paper. It is based on the inhibition effect of NH4+ on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and hypochlorous acid electrogenerated on-line. The sensor responds linearly to NH4+ concentration in 1.0x10(-6)-4.0x10(-9) g/ml range. A complete analysis could be performed in 1 min. The system is stable for 200 determination.
文摘为减少联合收获机振动对谷物流量传感器监测结果的干扰,设计了一种基于声学黑洞(ABH,acoustic black hole)原理的谷物流量传感器龙门支架减振结构,通过有限元方法分析减振结构的振动特性,分析了二维声学黑洞比例系数ε、幂函数指数m和半径R对其减振性能的影响规律。结果表明,声学黑洞能够显著降低龙门支架的振动,ε、m和R对声学黑洞减振性能的影响均未表现出明显线性关系,当ε=0.001 2、m=2.5、R=15 mm时声学黑洞的减振效果最好。以振动速度平方和作为优化目标,建立了多项式回归代理模型,通过遗传算法对声学黑洞比例系数ε、幂函数指数m和半径R的取值进行了优化。相比于未添加声学黑洞的原始龙门支架和初始声学黑洞方案,优化后龙门支架的振动速度平方和分别降低68.92%和2%,表明优化方案具有更佳的减振性能。提出的基于声学黑洞的减振结构和优化设计方法为农业机械被动宽频减振研究提供了理论参考。
