Multiphysics Modeling and Analysis of Droplet Impact on Tea Plant Leaves

The impact of warmer droplets on cold leaves in sprinkler anti-frost is a case of agricultural engineering involving multiphysics. This study models the leaf as an elastic body of finite thickness, incorporates the temperature field, and establishes a fluid–solid–thermal multiphysics coupling model. The effects of droplet velocity, droplet diameter, and initial temperature are analyzed accordingly. The results show that the higher the Weber number (We) of the droplet, the higher the droplet spreading coefficient and the leaf stress. The maximum spreading coefficient and maximum leaf strain at We of 1583.1 are 1.58 and 4.75 times those at We of 1055.4, respectively. There is a gradual decrease in the leaf deformation, a very rapid process, a cycle of about 10% of the spreading time. The temperature at the impact point on the leaf surface increased with the droplet’s initial temperature but could be influenced by an air bubble trapped at the droplet’s bottom. The modeling and analysis of the dynamics of droplet impact on plant leaves enabled a better understanding of the mechanisms of sprinkler frost protection.