微型电容式湿度探针的可行性研究

Feasibility Study of a Micro Capacitance Probe for Measuring Wetness of Wet Steam

湿蒸汽在热动力工程领域有着广泛的应用,准确测量流动湿蒸汽的湿度具有重要意义.基于电容法测湿的原理,设计了一种结构简单的微型湿度探针,以实现对湿蒸汽湿度便捷、实时的测量.基于集成电路芯片CAV444设计制作了测量电路,用来测量微型湿度探针的电容.基于该测量电路,分析了微型湿度探针的时漂特性,研究了流量对电容的影响,并通过空气流中喷水雾的方法模拟了探针对湿蒸汽流的响应.实验结果表明,利用该微型湿度探针测量流动湿蒸汽的湿度是可行的.

Wet steam is widely used in the field of thermal power engineering.Accurate measurement of the wetness of flowing wet steam is of great significance.Based on the principle of the capacitance method,a micro capacitance probe with simple structure was designed to conveniently measure the real-time wetness of flowing wet steam.A measuring circuit,which is based on the integrated circuit chips CAV444,was also designed to measure the capacitance of the micro probe.Using the measuring circuit,the drift characteristic of the micro capacitance probe and the influence of flow rate were tested.Besides,response of the probe to wet steam flow was also simulated by spraying water into the air flow.According to the test results,the proposed micro capacitance probe was proved to be feasible to measure the wetness of flowing wet steam.