A predictive model of frost formation on leaf surface and estimation of frost amount

Abstract

The massive frost that occurs each year in autumn and spring across subtropical and temperate regions cause severe damage to horticultural crops, therefore, the research for frost formation and estimation of frost amount are important for monitoring and regulation of frost damage. In this study, a predictive model of frost formation on leaf surface with the interaction of wet air phase and frost phase was established by Euler multiphase flow model. According to the variation of phase volume fraction, the evolution process of frost under non-stationary conditions was simulated using Fluent calculations based on leaf surface frosting mechanism. In addition, the influence of different surface temperatures, air velocities and humidity on frost amount were investigated deeply during simulation by building frost amount measurement device combined with microscopic image processing. The results showed that the frost amount increased mainly with decreased surface temperature under time-varying conditions, and reduce the velocity or increase humidity also has a beneficial effect. The estimation of frost thickness fell within confidence intervals up to 90%, with overall deviations in frost mass ranging from −8.4% to 23.8%. Eventually, the model was demonstrated that it could provide an acceptable prediction of frost formation and estimate of frost amount.