蒸汽湿度电容传感器内部电场与流场耦合特性数值研究

基于电介质极化和蒸汽流动的基本理论，利用FLUENT软件的二次开发功能，对蒸汽湿度电容传感器内部蒸汽流场和电场进行了理论分析和耦合特性的数值模拟。湍流模型采用标准k-ε模型，近壁区采用壁面函数法，电场和流场方程均使用SIMPLE算法。研究结果表明：当蒸汽为单相饱和蒸汽时，电容传感器内部电势由正极板向负极板逐渐减小，且变化较均匀，电荷主要分布在极板附近，内部区域无极化电荷；电场对流场的影响主要体现在极板附近蒸汽的径向流速上，最外层极板附近电场对流场的影响最大；流场对电场的影响主要体现在电极板的边缘效应上，有流场时极板附近的电场强度较无流场时低；数值模拟结果与实验结果的相符程度较好。

Numerical Simulation on Coupling Performance of Steam Flow Field and Electric Field in Capacitance Sensor Measuring Steam Wetness

Based on the theory of dielectric polarization and hydrodynamics, using the FLUENT UDF code, the coupling performances of the steam flow field and the electric field in the capacitance sensor were numerically simulated. The standard k-ε model, wall function and SIMPLE way were used. The results show that the voltage decreases gradually from positive plate to negative plate, and the change is even; water molecule is polarized, the polarized charge appears near the plates, and there is no polarized charge in the center of sensor when the dry saturation steam flows through the capacitance sensor; the radial velocity is different from with and without electric field in the capacitance sensor, and the difference is max near the outmost plate; the electric field near the plate is smaller when there is no flow field. The results of numerical simulation match with the results of experiment. The numerical simulation model is feasibility.