横摇晃荡对矩形工船养殖舱内流场与颗粒物去除的影响

Effect of transverse rolling on flow field and particle removal in the rectangular aquaculture tank

深远海养殖工船游弋式养殖是现代海洋渔业发展的一个重要的方向。基于FLOW-3D软件探究了横摇运动对舱内流场特征的影响,并在此基础上计算了不同横摇工况下流场中废弃颗粒物的去除情况。结果显示:控制横摇周期一定,随着横摇角度从0°增加到2°,舱内流速略有增加。而当横摇角度从2°增加到7°时,舱内流速出现大幅增加,v_(50%)从0.171 m/s增加到0.477 m/s;同时横摇角度的增大也使流速的整体分布更加离散。横摇角度幅值2°以内工况的流动均匀性指数主要集中在0.8~0.85,当横摇角度幅值增加到3°后,养殖舱流动均匀性显著降低,养殖舱内水体流动均匀性指数均小于0.8。当横摇角度幅值一定时,横摇周期缩短,养殖舱内流速急剧增大,各工况流速的v_(50%)与其他分位数呈线性增长趋势而舱内水体的流动均匀性变化并不显著。对于养殖舱内废弃固体颗粒物的去除,在横摇周期和颗粒物自身属性一定时,整个过程分为效果相反的前后两个阶段:从颗粒物投放进入流场至投放后的1 000 s内,横摇角度幅值越小,其去除速率越高;此后直至整个算例的计算结束,横摇角度越大,颗粒物去除速率越高。而横摇周期对养殖舱内颗粒物的去除排出基本没有影响,各个工况颗粒物去除的达标时间极为接近。

Cruise-type aquaculture on deep-sea aquaculture vessels is an important direction for developing of modern marine fisheries.The article explored the effect of transverse rolling motion on the flow field characteristics in the tank based on FLOW-3D software,and calculated the removal of waste particles in the flow field under different transverse rolling conditions on this basis.The results showed that when controlling the period of transverse rolling,the flow velocity in the aquaculture tank increased slightly as the amplitude of the transverse rolling angle increased from 0°to 2°.When the amplitude of the transverse rolling angle was increased from 2°to 7°,the flow velocity in the aquaculture tank showed a large increase,and the v_(50%)increased from 0.171 m/s to 0.477 m/s;the increase of the transverse rolling angle also made the overall distribution of the flow velocity more discrete.The flow uniformity index of the conditions with the transverse rolling angle amplitude of 2°or less is mainly concentrated in 0.8-0.85,while when the transverse rolling angle amplitude is increased to 3°,the flow uniformity of the aquaculture tank decreases significantly.The flow uniformity indices of the water in the aquaculture tank are all less than 0.8.When the amplitude of the transverse rolling angle is certain,the transverse rolling period is shortened,the flow velocity in the aquaculture tank increases sharply,and the v_(50%)of the flow velocity of each condition and the other quartiles show a linear growth trend while the uniformity of the flow of the water in the tank does not change significantly.For the removal of waste solid particles in the aquaculture tank,the whole process is divided into two phases with opposite effects when the period of transverse rolling and the properties of particles themselves are certain.From the time when the particles were released into the flow field to the 1000 s after the release,the smaller the amplitude of the transverse rolling angle was,the higher the removal rate was;thereafter,until the end of the calculation of the whole example,the larger the transverse rolling angle was,the higher the removal rate of the particles was.The period of transverse rolling did not effect the removal of particles in the aquaculture tanks,and the time to reach the standard for particles removal was very close for each condition.