【作者】 许文达；

【导师】 张涛；

【作者基本信息】 天津大学 ， 检测技术与自动化装置， 2013， 博士

【摘要】 水蒸汽是一种重要的二次清洁能源，在能源消耗上占居较大的比例，但由于其独特、复杂的物理特性，相对于水、电、天然气等其它能源介质，一直难于计量。蒸汽的准确计量是一个困扰计量检测的世界性难题。目前对于蒸汽流量计普遍采用空气或水代替蒸汽介质进行量值溯源，虽然取得了不错的效果，但此种方式无法真实反映蒸汽流量计的真实工况，检测介质的不同可能会引起计量偏差。蒸汽流量计计量溯源手段的不完善，以及缺乏在蒸汽实流检测下的实验研究，导致了蒸汽流量计量精度低，制约了蒸汽计量管理和仪表的发展。为深入分析蒸汽流量仪表在蒸汽介质下的计量特性，本课题研制了一套冷凝称重法蒸汽流量计量标准装置，该装置完善了我国蒸汽流量量值溯源传递体系。在此基础上采用蒸汽实流检测的方法，结合计算流体力学及热力学，对涡街流量计和V锥流量计的计量特性进行了深入研究和实验分析，得到了不同介质下涡街流量计和V锥流量计计量特性的差异；分析了产生该差异的机理；发现以水或空气为检定介质对蒸汽流量计进行标定，将会对计量结果产生一定的误差。因此，本文提出了采用水或空气替代蒸汽测量的仪表系数修正补偿方法，并利用CFD仿真软件对涡街和V锥流量计在不同介质条件下的流场进行了仿真分析。主要完成如下工作：利用计量标准装置对涡街流量计开展了空气、水、蒸汽三种不同介质的比对测试实验研究，得到了不同介质对涡街流量计的计量性能的影响差异，基于流体力学及卡门涡街的基本原理，建立了涡街流量计在蒸汽介质条件下的计量模型，并提出了不同介质条件下仪表系数的修正方法，从而为实验研究构建了理论依据。利用CFD仿真软件对涡街流量计在不同的介质下进行了仿真分析验证。鉴于V锥流量计缺乏蒸汽介质条件下的实验和理论分析，本文在水、负压空气、正压空气、蒸汽装置上分别对不同口径、不同β值的实验样机，在不同工况条件下开展了可膨胀系数实验研究，得到了V锥流量计在空气和蒸汽介质中可膨胀系数的经验公式数学模型。利用CFD仿真软件对V锥流量计的可膨胀系数进行了仿真分析研究，从仿真流场解释分析了不同介质的差异的机理，验证了实验结论。实现了对V锥流量计空气和蒸汽介质中的可膨胀系数仿真预估。研制了冷凝称重法蒸汽流量计量标准装置，对稳压容器、冷凝器进行分析计算，并采用CFD仿真软件进行了优化设计，对装置的技术指标进行了实验验证和分析。更多还原

【Abstract】 Vapour is an important clean secondary energy, which own the larger proportionin energy consumption. But compared with water, electricity, gas and other energymedium, vapour is difficult to measure due to its unique and complex physicalproperties. Accurate measurement of the steam has been a difficult measuringproblem in the world. The measurement widely uses air or water instead of steammedium for traceability. Although this method has obtained good results, but don’treflect the real condition of steam flowmeter, because different medium will causemeasurement error. Steam flowmeter has low accuracy, on account of steamflowmeter tracing method is not perfect, and lack of the steam flow experiments ondetection, which is the important factor of restricting steam metering management andinstrument development.A set of standard steam flow installation has been developed by usingcondensation weighing method to deeply analyze the measurement characteristics ofthe steam flowmeter in steam medium. The device improves the origin of steam flowvalue transfer system, which is helpful to improve the accuracy of steam flowmeasurement. On this basis, vortex flowmeter and V cone flowmeter measurementcharacteristics have been researched on the base of the real steam test flow method.Combined with computational fluid dynamics and thermodynamics, the differences ofthe measurement characteristics of vortex flowmeter are obtained under differentmedium; the mechanism of the difference has been analyzed; which will bring in acertain error on measurement results has been found that the steam flow meter iscalibrated with water or air as the test media. Therefore, meter factor correctionmethod has been put forward by using water or air substitute the steam. The flow fieldof vortex flowmeter and V-cone flowmeter in different media has been simulated byusing CFD simulation.The main research work is as follows:Comparison experiment of vortex flowmeter in air, water, steam has been done byusing the measuring standard device. The results showed that the different mediumhas affected on the measurement performance of vortex flowmeter. According to thebasic principle of fluid mechanics and the Carmen vortex, the mathematical model ofsteam vortex flow meter has been created, and the correction method of instrument coefficient of different media conditions is put forward so as to build a theoreticalbasis for experimental study. The vortex flowmeter is analyzed in different mediumby using CFD simulation software.There is less research on expansion coefficient of V cone flowmeter in the air andsteam medium conditions, especially lack of experiment and theory analysis.Researches on coefficient of expansion have been carried out under different diameter,different βprototype in different media, temperature, and pressure by using water,negative pressure air, positive pressure air and steam device respectively. The V coneflowmeter empirical correlation coefficient in air and steam medium is analyzed. TheV cone flowmeter coefficient of expansion has been analyzed by using the CFDsimulation software simulation, the mechanism of the differences in different mediahas been analyzed and explained from the simulation flow field explains and theexperimental results are verified. The V cone flow expandable coefficient in air andsteam medium is prediction by simulation.The condensation weighing standard method of steam flow instrument has beendeveloped to analyze the pressure vessel, the condenser system and the commutator.And the design has been optimized by using the CFD simulation software.Technology index of the apparatus is tested and analyzed.更多还原