Analysis and Test on Influence Factors of Dew Drop Condensation in Dew Point Hygrometer

The condensation process of dew droplets is influenced by many factors. A dew point condensation image observation system was built to improve the response speed of dew point detector under different measuring conditions. The basic mechanism of dew drop condensation growth was studied and the influence of various factors on the dew drop growth rate were analyzed. And the accuracy of the influence results was verified based on the improved Hough transform circle detection. The results show that the growth rate of dew droplets is affected by ambient temperature, dew point temperature, mirror temperature and air velocity. The observed variation of the average radius of dew droplets is consistent with the theoretical calculations. The maximum radius error is less than 4 μm, the initial error is larger, and the error oscillates in the middle and late stages of condensation. The establishment of condensation mechanism is helpful to solve the problem in fast determination of dew point temperature under the cold start of dew point meter, and to improve the response speed.