上游弯管对工业锅炉水流量测量准确性的影响
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摘要
为了研究上游弯管的设置对超声波流量计测量工业锅炉水流量准确性的影响,基于时差法超声波流量计测量原理,建立不同直径、不同流量的锅炉管道弯管物理模型,给定相应边界条件,采用有限体积法进行数值模拟求解,结果发现弯管下游管道内的速度呈非理想均匀分布状态,对水流量测量的准确性影响较大:流量的理论测量值均比实际值小,且在不同测量位置,测量的相对误差在-15%～-1%之间波动;在前10 D范围内,测量的准确度随测试位置与弯管距离的增大而增加,在10～40 D范围内,测量的准确度在5%以内;同一测量条件下,流量测量的准确度随管内工质流量的增大而减小;在流量全测量范围内,管径越大,流量测量的相对误差的变化区间越小,即误差曲线越平缓。
This paper focus on the influence of water flow measurement accuracy by using ultrasonic flowmeter in industrial boiler when setting upstream pip bends. Based on measuring principle of time difference ultrasonic flowmeter,the physical model of boiler pipe bends in different diameter and different flow were established and the corresponding boundary condition was given,numerical simulation was proceeded using finite volume method. The result shows that the speed of the fluid in downstream pip bend is not in ideal uniform distribution state which has a larger influence on the accuracy of flow measurement: the theoretical flow measurements are smaller than the actual value,and in the different measuring position,the relative error fluctuation of the measurement is within-15% ～-1%; the measurement accuracy increases with the raise of the distance between test locations and pip bends inthe range of the first 10 times pip diameter and the measurement accuracy is within 5% in 10 D ～ 40 D range; under the same measurement condition,the flow measurement accuracy decreases with the increase of tube working medium flow; at all the measurement range of the flow,the relative error of the flow measurement of changes becomes smaller when the diameter is larger than before which means the error curve is flat.
This paper focus on the influence of water flow measurement accuracy by using ultrasonic flowmeter in industrial boiler when setting upstream pip bends. Based on measuring principle of time difference ultrasonic flowmeter,the physical model of boiler pipe bends in different diameter and different flow were established and the corresponding boundary condition was given,numerical simulation was proceeded using finite volume method. The result shows that the speed of the fluid in downstream pip bend is not in ideal uniform distribution state which has a larger influence on the accuracy of flow measurement: the theoretical flow measurements are smaller than the actual value,and in the different measuring position,the relative error fluctuation of the measurement is within-15% ～-1%; the measurement accuracy increases with the raise of the distance between test locations and pip bends inthe range of the first 10 times pip diameter and the measurement accuracy is within 5% in 10 D ～ 40 D range; under the same measurement condition,the flow measurement accuracy decreases with the increase of tube working medium flow; at all the measurement range of the flow,the relative error of the flow measurement of changes becomes smaller when the diameter is larger than before which means the error curve is flat.
引文
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[14]晁智强,盛锋,韩寿松.时差法超声波流量计误差分析与研究[J].液压与气动,2009(6):64-67.
[15]陈红.上游弯管对超声波流量计测量误差的影响[D].杭州:中国计量学院,2014.
[16]王梅.便携式超声波流量计在循环水管道上的应用[J].数字技术与应用,2012(6):113-115.
[17]陈刚,郭祎,于涛,等.兰郑长管道超声波流量计测量误差的修正[J].油气储运,2012(11):877-879+887.
[18]刘敦利,蔡勤.管道对超声波流量计计量准确度的影响分析[J].中国测试,2014(4):42-44.
[19]危鄂元.基于时差法的单声道气体超声波流量计的研究[D].杭州:浙江大学,2014.
[20]吴瑞基.超声波流量计的误差分析与修正[J].甘肃冶金,2005(3):105-106.
[2]王中伟,管坚,常勇强,等.中国工业锅炉能效测试与评价能力建设进展[J].中国特种设备安全,2015(9):9-13.
[3]湛含辉,朱辉,陈津端,等. 90°弯管内二次流(迪恩涡)的数值模拟[J].锅炉技术,2010(4):1-5.
[4]孙业志,胡寿根,赵军,等.不同雷诺数下90°弯管内流动特性的数值研究[J].上海理工大学学报,2010(6):525-529.
[5] AZZOLA J. Developing Turbulent Flow in a U-bend of Circular Cross-section[J]. Measurement and Computation Trans ASME,J of Fluids Eng,1986,108:214-221.
[6]邱立杰,张国福,郝明.基于FLUENT的弯管内部流场的数值模拟[J].辽宁石油化工大学学报,2013(1):48-52.
[7]纪宏超,李耀刚,郑镭,等.基于fluent的弯管流动模拟研究[J].河北联合大学学报(自然科学版),2013(1):73-76.
[8]温良英,张正荣,陈登福,等.弯管内流体流动的模拟计算与实验研究[J].计量学报,2005(1):53-56.
[9]蓝立伟.导流弯管数值模拟分析[J].广州化工,2014(1):105-106.
[10]田野,王岳,郭士欢,等.常见流量计的应用[J].当代化工,2011(12):1294-1296+1304.
[11]苏菲.超声波流量计的应用研究[J].化工与医药工程,2014(2):40-43.
[12]兰纯纯.时差法超声波流量计的研究[D].重庆:重庆大学,2006.
[13]邓凯.基于时差法超声波流量计的设计与研究[D].广州:华南理工大学,2013.
[14]晁智强,盛锋,韩寿松.时差法超声波流量计误差分析与研究[J].液压与气动,2009(6):64-67.
[15]陈红.上游弯管对超声波流量计测量误差的影响[D].杭州:中国计量学院,2014.
[16]王梅.便携式超声波流量计在循环水管道上的应用[J].数字技术与应用,2012(6):113-115.
[17]陈刚,郭祎,于涛,等.兰郑长管道超声波流量计测量误差的修正[J].油气储运,2012(11):877-879+887.
[18]刘敦利,蔡勤.管道对超声波流量计计量准确度的影响分析[J].中国测试,2014(4):42-44.
[19]危鄂元.基于时差法的单声道气体超声波流量计的研究[D].杭州:浙江大学,2014.
[20]吴瑞基.超声波流量计的误差分析与修正[J].甘肃冶金,2005(3):105-106.
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