养殖网箱网衣清洗设备喷嘴的设计及力学特性分析

Design and mechanical characteristics analysis of nozzles for net cleaning equipment in aquaculture cage

以提升清洗设备喷嘴清洗清洁度为目的,采用k-kl-w三方程湍流模型及有限元理论方法分析3类喷嘴孔内压强分布特性、速度分布特性和空化程度情况。结果显示:1)与锥型截面喷嘴和圆弧型截面喷嘴相比,突变型截面喷嘴在结构缩颈处有单位时间最大速度变化量224.13 m/s,具有更大的概率发生空化效应;2)锥型截面喷嘴与圆弧型截面喷嘴的空化区域远小于突变型喷嘴,其最大气相体积分数约为同等条件下突变型截面喷嘴的37.5%;3)高压流体作用下突变型截面喷嘴的流体状态为湍流,与锥型截面喷嘴和圆弧型截面相比湍流动能和湍流强度最大;4)圆弧型截面喷嘴湍流动能和湍流强度均趋于零,流体状态为层流,与突变型和锥型截面喷嘴相比,圆弧型截面喷嘴对保持流体层流性有较好的稳定性。喷嘴优化分析结果显示,通过增加突变型截面的喷嘴结构能显著提升喷嘴的空化强度。

For the purpose of improving the cleanliness of nozzles for cleaning equipment,the k-kl-w three-equation turbulence model and finite element theory are used to analyze the pressure distribution,velocity distribution and cavitation degree of the three types of nozzles in this paper.The results show that:1)compared with conical and circular cross-section nozzles,the maximum velocity variation per unit time of the abrupt cross-section nozzle is 224.13 m/s at the neck of the structure,and the abrupt cross-section nozzle is more likely to have the effect of cavitation;2)the cavitation areas of conical and circular cross-section nozzles are much smaller than that of abrupt cross-section nozzle,and the maximum vapor volume fraction of the two types of nozzles is about 37.5%of that of abrupt cross-section nozzle under the same conditions;3)the fluid of the abrupt cross-section nozzle is turbulent under high pressure fluid,and the turbulent kinetic energy and turbulent intensity are the largest compared with conical and circular cross-section nozzles;4)the turbulent kinetic energy and turbulent intensity of the circular cross-section nozzle are almost equal to zero,and the fluid is a laminar flow.The circular cross-section nozzle may maintain better stability of fluid laminar flow compared with abrupt and conical cross-section nozzles.The analysis results of nozzle optimization show that the cavitation strength of nozzles can be significantly enhanced by increasing the nozzle structure of abrupt cross-section.