雾培叶菜根冠比不合理、难调控的现状严重影响了叶菜雾化栽培的经济效益，是迫切需要突破的瓶颈。项目选择生菜作为研究对象，将开展以下研究：通过建立低速细雾滴与单根相互作用力学模型，仿真研究雾滴被单根弹落以及破碎的过程;应用变分原理、JKR模型、基于傅里叶变换的单根-雾滴多尺度边界条件、根薄膜在张拉变形中的弹性能和粘附能，建立单根雾滴黏附接触理论模型；提出气力式低频超声静电雾化原理; 通过有限元优化拉瓦尔管、建立双级谐振腔的平面对称流体流动模型以优化设计双级Hartmann谐振腔、研究谐振腔与静电场的耦合雾化机理，创制气力式低频超声静电喷头以生成高粘附性细雾滴；在建立根系分形模型的基础上，建立雾滴根系粘附面积与生菜根冠比的关系数学模型；以生菜根冠比最优为目标，研究生菜不同生长阶段的喷雾调控参数。项目拟通过调控根系雾滴粘附面积，实现作物根部氧气、养分和水分合理供给，提高生菜冠层占整株作物的比例。

The current situation of unreasonable and difficult regulation of the ratio of root to shoot of aeroponic leaf vegetables has seriously affected the economic benefit of fog-culture leaf vegetables, which is the bottleneck that needs to be broken through urgently at present. Representative leaf vegetable – lettuce is selected as the research object and this project will carry out the following research: .(1).The process of the droplet being bounced off and broken by the root will be simulated by establishing the mechanical model of the interaction between the low-speed fine fog droplets and a single root..(2).The adhesion contact theoretical model of root droplets will be established by variational principle, applying the multi-scale boundary conditions based on Fourier transform, JKR model, the elastic energy and adhesion energy of root film in tension deformation..(3).The principle of pneumatic low frequency ultrasonic electrostatic atomization will be proposed in this project..(4).An air-power low-frequency ultrasonic electrostatic nozzle will be designed to generate highly adherent droplets yy using 3-D finite element models to optimize the design of the laval tubes, creating a two-level harmonic fluid flow model to optimize the design of the two-stage Hartmann resonant cavity and coupling atomization mechanism between resonator and electrostatic field,..(5).The mathematical model of the relation between the area of droplet adhering root and the ratio of lettuce root to shoot will be studied based on the establishment of roots fractal model,.(6).A spray control model of lettuce at different growth stages will be established with the aim of optimizing the ratio of root to shoot. .The project aims to improve the proportion of lettuce shoot in the whole plant by regulating the area of droplets adhering roots to realize the reasonable supply of oxygen, nutrients and water in the root of crops.