Abstract: In order to solve the problem that there are a large number of highpressure nozzles in the executive parts of the lotus root harvester in a large area of shallow water field, and the flow velocity difference between the nozzles is too large, which leads to the decline of the recovery efficiency of lotus root and the uneven quality of lotus root, this paper optimizes the executive parts of the lotus root harvester jet system. As an important component of the actuator, the stability of the jet has a great influence on the harvesting efficiency and scouring effect of lotus root. In order to reveal the influence of the connection process of the high pressure nozzle and the shape and diameter of the nozzle on the jet stability, based on the EdemFluent software, this paper carries out the environment modeling of the internal flow field and the coupling simulation of the nozzle of the executing part. It is found that by changing the shape of the nozzle to increase the chamfer and adjusting the diameter of each nozzle to the appropriate difference value, the stability of the nozzle is obviously improved. The standard deviation of the flow velocity fluctuation is changed from 0.164 m/s to 0.020 m/s. The average excavation depth is changed from 33.50 cm to 36.07cm, and the standard deviation of excavation depth is changed from 1.71 to 0.69. 

Key words: lotus root harvester, firing system, EDEMFluent  , coupling simulation, water stability, fluid mechanics

摘要： 为解决大面积的浅水藕田地区的莲藕采收机执行部件高压喷头的个数较多，容易出现各喷头间流速差过大的现象，导致莲藕采收率的下降和莲藕品质的参差不齐的问题，对莲藕采收机射流系统执行部件进行优化。喷头作为执行机构的重要组件，其射流的稳定性对莲藕采收的效率以及冲刷效果有着重大的影响。为揭示高压喷头的连接工艺和喷头形状、口径对射流稳定性的影响，基于EDEMFluent软件对内部流场进行环境建模以及对执行部件的喷头进行耦合仿真模拟。试验发现：改变喷头的形状增加倒角，调整各喷头出水口直径到恰当的差值对喷头出水稳定性有明显的改观，流速波动标准差由0.164m/s改变为0.020m/s；平均挖掘深度由33.50cm改变为36.07cm，挖掘深度标准差由1.71cm改为0.69cm。

关键词: 莲藕采收机, 射流系统, EDEMFluent耦合仿真, 出水稳定性, 流体力学