基于CFD数值模拟的单罐真空吸鱼泵研制

Development of a single-tank vacuum fish pump based on computer fluid dynamic (CFD) numerical simulation

为满足池塘养殖对自动化捕捞装备的迫切需求,设计了一种适合池塘使用的小型真空吸鱼泵,并利用计算流体力学软件(computer fluid dynamic, CFD)数值模拟技术研究了单罐真空吸鱼泵内部的气液两相流的流动特性,重点分析了3种不同流速(1.0、1.5、2.0 m/s)下吸鱼泵内部回流、旋涡和速度跳跃等流动特性的演化及发展规律。结果表明:数值模拟计算显示,当进鱼管道抽吸速度为1.0 m/s时,鱼体损伤率相对较低,当进鱼管道抽吸速度为1.5、2.0 m/s时,鱼体损伤率相对较高,但吸鱼速度较快;基于数值模拟计算结果,研制了一种小型单罐真空吸鱼泵,同时选用草鱼、鲤、鲫、鲢和鳙5种鱼分别进行了单独抽吸试验验证,在最优吸取条件(抽吸速度为1.0 m/s)下,吸鱼量最大可达23 t/h,吸鱼泵可实现20 s吸鱼、10 s放鱼交替循环作业,鱼体损伤率最大为2%。研究表明,本试验中设计的小型单罐真空吸鱼泵能够实现对活鱼的高效自动吸捕与转运,可为设计开发池塘养殖用高效真空吸鱼泵提供有益参考。

In order to fulfill the urgent needs of pond aquaculture for the automatic fishing equipment, a small vacuum fish pump wisely applied in an aquaculture pond was designed using computer fluid dynamic(CFD) numerical simulation technology and the gas-liquid two-phase flow in a single tank vacuum fish pump was investigated, focusing on analysis of the fish pump’s backflow, vortex and velocity jump situations under flow rate of 1.0, 1.5 and 2.0 m/s. The results showed that there was low fish damage rate at the water suction speed of 1.0 m/s at the fish inlet pipe;the relatively high fish damage rate was at the fast suction speed including the water suction speed of 1.5 and 2.0 m/s at the fish inlet pipe. Also, a type of single tank vacuum fish pump was prepared based on the numerical calculation results and then grass carp Ctenopharyngodon idella, common carp Cyprinus carpio, crucian carp Carassius auratus, silver carp Hypophthalmichthys molitrix, and bighead carp Aristichthys nobilis were selected for separate suction test verification. Test results indicated that the maximum fish suction amount of 23 t/h was observed at the optimal suction speed of 1.0 m/s, with the fish suction for 20 seconds, fish release for 10 seconds, and the maximum damage rate of 2% for fish body. The findings show that the small vacuum fish pump designed in this experiment can realize efficient and automatic capture and transfer of live fish, which tends to provide a proper theoretical guidance and reference with the future’s design and development of the high-efficiency vacuum fish pomp for pond aquaculture.