袁太平,胡昱,王绍敏,陶启友,刘海阳,黄小华,郭根喜(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)
YUAN Taiping, HU Yu, WANG Shaoming, TAO Qiyou, LIU Haiyang, HUANG Xiaohua, GUO Genxi(South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangdong Cage Engineering Research Center, Guangzhou 510220, China)
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。
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