基于CFD的循环生物絮团系统养殖池固相分布均匀性评价  

Solid phase distribution simulation of culture pond with recirculating biofloc technology based on computational fluid dynamics

作　　者：史明明[1] 阮贇杰[1,2] 刘晃[3] 郭希山[1] 叶章颖[1] 韩志英[1] 朱松明[1] Shi Mingming Ruan Yunjie Liu Huang Guo Xishan Ye Zhangying Han Zhiying Zhu Songming(College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China Department of Biological and Environmental Engineering, Cornell University, Ithaca 14850, USA Fishery Machinery and Instrument Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200092, China)

机构地区：[1]浙江大学生物系统工程与食品科学学院,杭州310058 [2]美国康奈尔大学生物与环境工程系,伊萨卡14850 [3]中国水产科学研究院渔业机械仪器研究所,上海200092

出　　处：《农业工程学报》2017年第2期252-258,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金青年基金(31402348);十二五科技支撑计划项目(2014BAD08B09);农业部渔业机械仪器研究所重点实验室开发基金(2015);中国博士后基金项目(2014M551747)

摘　　要：为探索循环生物絮团系统相对原位生物絮团系统在生物絮团分布均匀性方面的改善,以欧拉-欧拉多相湍流模型为理论框架,运用计算流体力学(computational fluid dynamics)技术,对两种系统养殖池固液气三相三维流动进行了数值模拟,分析了两种养殖池的液相速度云图、液相流线图以及固相分布特性。模拟结果表明:在水力停留时间为0.90 h时,循环养殖池流场相对复杂,流向变化较乱且分布于整个空间,紊流相对剧烈,流场速度大小分布更均匀,死区相对较少,固相主要分布在中心大范围区域,便于循环,在底部未出现沉积现象,能够避免生产中由于生物絮团在桶底角处的沉积造成厌氧病菌的滋生。另外,循环养殖池生物絮团固相体积分数约为0.1,比较适宜罗非鱼等养殖对象的生长。通过与实测数据对比,模型的模拟值误差均在20%之内,模拟结果可信,该研究说明循环生物絮团系统能够解决原位生物絮团系统中生物絮团分布不均匀以及流场死角多的问题。Biofloc technology（BFT） has been widely used in situ tilapia rearing for its benefits such as saving protein-feed and reducing the adverse impacts on environment. And biofloc concentration has huge effect on aquaculture system. More specifically, TSS（total suspend solid） and the uniformity of the biofloc distribution can greatly affect cultured animals on feeding enthusiasm, and high TSS even will threat the survival of breeding objects. In production, because of the biofloc sedimentation, the bottom of traditional BFT system usually extremely high, so the recirculating biofloc technology（RBFT） system has become a hot topic in recent study. To investigate the improvement on biofloc distribution uniformity of RBFT system compared with situ BFT system, an Euler-Euler multi-phase turbulence 3-D model combined with the kinetic theory of granular flow was applied to simulate the solid-liquid-gas three-phase flow in culture ponds of two kinds of BFT system. At first, the tank meshing was finished based on the commercial software Workbenching 15.0. The grid independent validation was done to choose the acceptable mesh. At last, the mesh was imported in numerical simulation software（Fluent） to analyze the velocity contours and streamlines of liquid phase, distribution characters of solid phase in these two models. In this simulation, pressure-based solver and second-order implicit transient formulation were adopted. The boundary conditions of water and air inlet were set as velocity, and their outlet were regard as pressure outlet equated to the local atmospheric pressure. What＇s more, according to the SIM-PLE algorithm, pressure-velocity coupling was calculated. The bioflocs were regarded as to be distributed in the bottom initially. Unsteady simulations were performed when all residuals fall below 10-3, while 40 iterations per time step were used to ensure numerical stability. To have an accurate results, third-order monotone upstream-centered schemes for conservation laws（MUSCL） was used. The sim

关 键 词：水产养殖 流体力学 流场 循环生物絮团系统 养殖池 水力停留时间 多相流 

分 类 号：S969[农业科学—水产养殖]