3D Modeling of Condensing and Superimposing Deltamethrin Droplets on Strawberry Leaves Surface from Dynamic Wetting Process Monitoring Data

It is imperative to investigate the behaviour of droplet superimposed condensation of deltamethrin reagent on the strawberry leaf surface, and the dynamic variation rule of its contact angle. The microinjector was utilised to conduct the experiment of droplet superposition and condensation. The surface tension of deltamethrin droplets was measured by means of an optical contact angle meter, and the wetting parameters such as contact angle, volume and spreading diameter were obtained by observing the leaf surfaces of various parts of strawberries during the dynamic process of superimposed condensation. A model was constructed by establishing the relationship between the contact angle and the coordinates of the observation point and time through the spatial fitting interpolation method. This model is a three-dimensional dynamic trend surface model of contact angle for droplet superposition and condensation. The findings indicated that the surface tension of the deltamethrin drop was 28.92 ± 0.2 mN·m-1. The interval between the superposition of two droplets and the subsequent condensation of a new droplet was found to be within 0.5 seconds. The time taken for a new droplet to form was found to be between 0.0356 and 0.0476 seconds.The change of contact angle during the processes of superposition and coalescence can be broadly categorised into three distinct stages: namely, sharp oscillation, slight decrease and gentle stabilisation. The volume of the new droplet formed by the superposition and condensation was found to be 1.05 to 1.93 times that of a lying droplet. 1.93 times that of a lying droplet. The maximum increase in the spreading diameter of the superimposed and condensed droplets was 40.29%.The three-dimensional dynamic trend surface model can reflect the overall spatial-temporal change trend of the contact angle in the process of superposition and coalescence. The model successfully passed the overall significance F test and each coefficient of statistical T test, and demonstrated a satisfactory time interpolation effect. The experimental verification demonstrates that the predicted contact angle value of the model is consistent with the measured value.