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

  

  1. (South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangdong Cage Engineering Research Center, Guangzhou 510220, China)
  • Online:2020-09-16 Published:2020-04-20

养殖网箱网衣清洗设备喷嘴的设计及力学特性分析

  

  1. (中国水产科学研究院南海水产研究所，广东省网箱工程技术研究中心，广东广州  510220)
  • 作者简介:袁太平（1992—），男，研究实习员，硕士，研究方向：渔业设施与装备技术。E-mail:ytp0720@163.com
  • 基金资助:
    中国水产科学研究院南海水产研究所中央级公益性科研院所基本科研业务费专项（2019TS17）；国家自然科学基金资助项目（31772897）；海洋经济创新发展区域示范专项（Bhsfs012）；现代农业产业技术体系专项资金(CARS-47); 农业农村部外海渔业开发重点实验2019年度开放基金(LOF 2019-05)

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Abstract:  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 micro-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.

Key words: Mechanical characteristics, micro-nozzles, finite element method, net cleaning  
 

摘要： 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类微型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。

关键词: 力学特性, 微型喷嘴, 有限元方法, 网衣清洗