文丘里管内湿天然气流动特性研究

发布时间：2018-01-21 01:57

本文关键词： 文丘里管湿天然气流动特性静压分布数值模拟　出处：《西安石油大学》2016年硕士论文　论文类型：学位论文

【摘要】：湿天然气流过文丘里管时,由于液相的存在会使压差值比等量的气相单独流过时虚高。目前对文丘里管在湿天然气测量方面已经做了大量的实验和理论研究,但对其流动特性依然没有充分理解。各研究者都是在实验的基础上根据均相流和分相流理论建立湿天然气流量预测虚高模型。但是这些模型没有考虑湿天然气的真实流动特性,误差相对较大且使用范围受到限制。此外,在进行实验研究时,由于实验设备的限制,没有对液相体积分数较大的湿天然气进行研究。计算流体动力学(CFD)方法可以克服实验设备的限制,且精度较高需要的时间较短。因此,本文将采用CFD数值模拟和理论分析相结合的方法对文丘里管内湿天然气流动特性进行研究。首先,利用Fluent软件采用标准k-ε湍流模型和离散相(DPM)模型对文丘里管内的湿天然气进行了数值模拟。经过与英国国家工程实验室NEL的实验数据进行对比,数值结果的相对误差在±5%以内,平均均方根误差小于2.22%,验证了CFD方法的正确性。随后进一步增大液相体积分数进行模拟,获得了湿天然气的流场分布云图、液滴浓度分布云图和壁面静压曲线,并对数值结果进行了分析和讨论。然后,以环状—雾状流为基础建立了文丘里管内湿天然气静压分布模型,并利用Peining Yu et al和挪威SINTEF实验数据对该模型进行了验证。与Peining Yu et al的静压模型相对误差为±15%相比,该模型相对误差在±7%以内,性能有所改进。结果表明影响总压降的主要因素是加速压降,其次是摩阻压降,液滴夹带压降的影响相对较小。最后,从湿天然气测量虚高的定义出发对De Leeuw模型进行了改进。经过与NEL和CEESI实验数据进行对比,该改进模型与实验数据吻合的很好,误差都在+5%以内。通过与前人文丘里管虚高预测模型进行比较,该改进模型的均方根误差都最小,性能相对较好。
[Abstract]:When wet natural gas flows through Venturi tube, the pressure difference value is higher than that of the same gas phase when it flows alone because of the existence of liquid phase. At present, a large number of experiments and theoretical studies have been done on the measurement of wet natural gas in Venturi tube. However, the flow characteristics of wet natural gas are still not fully understood. Based on the theory of homogeneous flow and split flow, all researchers have established virtual high prediction models of wet natural gas flow. However, these models do not take into account the flow characteristics of wet natural gas. Real flow characteristics. The error is relatively large and the range of use is limited. In addition, when the experimental research is carried out, because of the limitation of the experimental equipment. The computational fluid dynamics (CFD) method can overcome the limitation of experimental equipment, and the time required for higher accuracy is shorter. In this paper, CFD numerical simulation and theoretical analysis are used to study the flow characteristics of natural gas in Venturi pipe. The standard k- 蔚 turbulence model and discrete phase DPM are used in Fluent software. The model is used to simulate the wet natural gas in Venturi pipe. The model is compared with the experimental data of NEL. The relative error of the numerical results is less than 卤5%, and the mean RMS error is less than 2.22, which verifies the correctness of the CFD method. The flow field distribution cloud diagram, droplet concentration distribution cloud diagram and wall static pressure curve of wet natural gas are obtained, and the numerical results are analyzed and discussed. A hydrostatic pressure distribution model of wet natural gas in Venturi pipe was established based on annular and foggy flow. The experimental data of Peining Yu et al and Norway SINTEF were used to verify the model. Al's relative error of hydrostatic pressure model is 卤15%. The relative error of the model is less than 卤7%, and the performance is improved. The results show that the main factor affecting the total pressure drop is the acceleration pressure drop, followed by the friction pressure drop, the droplet entrainment pressure drop is relatively small. Finally. The de Leeuw model is improved from the definition of virtual height of wet natural gas. Compared with the experimental data of NEL and CEESI, the improved model is in good agreement with the experimental data. The errors are within 5%. Compared with the previous Venturi model, the improved model has the smallest root mean square error and better performance.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE863.1

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