绝缘性流体管内流动时静电电荷密度计算

摘要

Accumulation of electrostatic charge is one of the inducing factors causing safety accidents such as explosion during the storage and transportation process of refrigerants/cryogens as well as petroleum products. A theoretical model of static electrification in low temperature insulating fluids flowing in pipes was established, which enables prediction of the transient behavior of the electrostatic charge density of several flowing fluids including liquid hydrogen. By solving the ionic flux density equation and the Poisson equation, the relationship between the electrostatic charge density and the impact parameters such as the pipe radius, and the properties (temperature, pressure and Reynolds number) of several flowing fluids including liquid hydrogen was studied. The results showed that the charge density generally has positive correlation with the above parameters. However, their influencing principles are specific and sensitive to the flowing conditions (laminar or turbulent), and the thermophysical properties such as saturation degree, temperature, pressure and conductivity.%静电积聚是引发制冷低温工质和化工油品在储存和运输过程爆炸等安全事故的重要原因之一。本文建立了低温绝缘性流体在管内流动时静电起电过程的瞬态理论模型，用于研究包括液氢在内的流体静电电荷密度随时间的变化规律。通过解析方法求解离子流量密度方程和静电场泊松方程，分析了管道半径、液氢等低温流体物性（温度、压力）及雷诺数等参数对流体电荷密度大小的影响。结果表明，电荷密度与上述参数在整体上均成正相关关系，但各参数对电荷密度的影响规律随流体的流动状态（层流或紊流）以及热物性诸如饱和程度、温度、压力及电导率等的变化而不同。