液氢流体输送和贮存静电积聚特性研究

发布时间：2018-05-06 17:42

本文选题：流体静电 + 计算模型　；参考：《上海交通大学》2015年硕士论文

【摘要】：随着航天和能源工业的迅速发展,液氢、液氧和液化天然气等低温流体的应用越来越广泛。这类流体大多具有高绝缘性,在输送过程中管壁产生摩擦从而产生静电并不断积聚,流体带电问题已成为影响其安全的重要因素之一,引起极大关注。流体带电问题受到流速、温度、固体材料性质等多方面的影响,涉及到流体力学、静电学和热力学等多个学科,深入开展对该问题的研究具有重要的理论和实际意义。本文在理论研究基础上建立了一个适用性广的计算模型,并通过搭建实验台进行了相关测试,验证了所提出理论模型的准确性,并将模型应用于液氢的实际运输算例,为之提供指导。具体地,首先在文献调查的基础上,介绍了流体静电特性的研究现状和所得成果,阐述了流体带电的基本机理和影响因素。之后建立了管内流流体静电电荷密度计算的数学物理模型,针对流体带电问题中的流动特点,提出用二阶迎风格式和中心差分格式求解电荷密度方程,使用Matlab数学工具得到仿真结果,得到了速度、温度等参数对管内电荷密度分布的影响。随后,以模型验证为出发点,确定了实验方法和实验内容,设计了实验装置,以旋转圆盘系统为基础搭建了流体起电速率测试实验台进行测试,根据所得到的实验结果对速度、温度、转盘材料等因素的影响进行了定量和定性分析。理论和实验的研究结果均明显体现出速度对于流体带电的决定性影响作用。然后以静态储存于储罐内的带电流体为研究对象,得到储罐内流体静电位的计算模型,通过数学求解得到了流体电荷密度、相对介电常数和储罐半径、径高比等结构参数对储罐内静电位分布的影响规律。根据理论计算和实验研究的结果,提出了相关的预防静电措施。最后综合对比理论计算模型和实验测试的结果,发现两者具有一定的吻合度,从而验证了该理论计算模型对于流体带电特性研究的适用性,并在此基础上将该模型应用到低温流体液氢的静电积聚特性研究中,得到了对实际液氢输送和储存中消除或者抑制静电产生的有益指导性结果。
[Abstract]:With the rapid development of aerospace and energy industry, cryogenic fluids such as liquid hydrogen, liquid oxygen and liquefied natural gas are more and more widely used. Most of these fluids have high insulation, friction of pipe wall produces static electricity and accumulates continuously in the course of transportation. The problem of fluid electrification has become one of the important factors affecting its safety, which has aroused great concern. The problem of fluid electrification is affected by flow velocity, temperature, properties of solid materials and so on. It involves many subjects, such as hydrodynamics, electrostatics and thermodynamics, etc. It is of great theoretical and practical significance to study the problem in depth. On the basis of theoretical research, a widely applicable calculation model is established in this paper, and the accuracy of the proposed theoretical model is verified by setting up an experimental bench to verify the accuracy of the proposed model, and the model is applied to the actual transportation of liquid hydrogen. To provide guidance. Specifically, based on the literature investigation, this paper introduces the current situation and achievements of electrostatic characteristics of fluid, and expounds the basic mechanism and influencing factors of fluid electrification. Then, a mathematical and physical model for calculating electrostatic charge density of fluid in pipe is established. According to the flow characteristics of fluid charging problem, the second order upwind scheme and central difference scheme are proposed to solve the charge density equation. The effect of velocity and temperature on the distribution of charge density in the tube is obtained by using the Matlab mathematical tool. Then, with the model verification as the starting point, the experimental method and content are determined, and the experimental device is designed. Based on the rotating disk system, a test bench is set up to test the starting power rate of the fluid, and the velocity is measured according to the obtained experimental results. The effects of temperature, rotating disc materials and other factors were analyzed quantitatively and qualitatively. Both theoretical and experimental results show the decisive effect of velocity on fluid charge. Then taking the charged fluid stored in the tank as the research object, the calculation model of the electrostatic potential of the fluid in the tank is obtained, and the charge density, the relative dielectric constant and the radius of the storage tank are obtained by mathematical solution. The influence of structure parameters such as diameter to height ratio on electrostatic potential distribution in storage tank. According to the results of theoretical calculation and experimental study, the relative measures of preventing static electricity are put forward. Finally, by comparing the theoretical calculation model with the experimental results, it is found that the two models have a certain degree of agreement, which verifies the applicability of the theoretical calculation model to the study of fluid electrification characteristics. On this basis, the model is applied to the study of electrostatic accumulation characteristics of liquid hydrogen in cryogenic fluids, and some useful guidance results are obtained for eliminating or inhibiting electrostatic generation in actual liquid hydrogen transportation and storage.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.2

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