Numerical modelling of fluid flows in a recirculating aquaculture system

Myera集团开发了一种创新的循环水养殖系统（RAS），希望成为偏远地区粮食安全解决方案的领导者。RAS基于模块化水箱设计，在鱼类养殖中提供有针对性的喂养，药物和环境控制。这种新颖的设计使用气升泵送机制来控制水流速度，通过运动优化鱼类健康，同时促进气体交换和废物去除。气升泵中的流体流动涉及两相（气液）泡状流与质量交换的非常复杂的组合。相互作用以改变流体速度和空气交换的参数是空气的质量流率、气泡尺寸、空气提升管几何形状以及与模块化罐的管道连接。预测如何改变这些参数将影响系统的性能是非常具有挑战性的，但必须改善的system.The设计的主要方面，这项工作提出的是开发一个详细的数值模型的三维两相流体流动的气升泵的RAS。该模型将使用最先进的计算流体动力学（CFD）软件，并根据实验数据进行验证。由此产生的模型将预测流体流动和质量传递，并响应于几何形状和操作条件的变化。该公司将能够使用该模型进行设计变更的虚拟原型。这将节省时间和金钱，以改进全面生产所需的设计。

A new, innovative, recirculating aquaculture system (RAS) has been developed by the Myera Group that wants to be a leader in food security solutions for remote regions. The RAS is based on a modular tank design that provides for targeted feeding, medication, and environmental control in the raising of fish stocks. The novel design uses an airlift pumping mechanism to control water velocity for optimising fish health through exercise, while simultaneously promoting gas exchange and removal of waste.The fluid flow in the airlift pump involves a very complicated combination of two-phase (gas-liquid) bubbly flow with mass exchange. The parameters that interact to change the fluid velocity and air exchange are the mass flow rate of air, the bubble size, the air lift duct geometry, and the piping connections to the modular tank. Predicting how changing any of these parameters will affect the performance of the system is very challenging, yet is essential to improve the design of the system.The main aspect of this proposed work is to develop a detailed numerical model of the three-dimensional two-phase fluid flow in the airlift pump of the RAS. This model will use state-of-the-art computational fluid dynamics (CFD) software and validate against experimental data. The resulting model will predict the fluid flow and mass transfer and be responsive to changes in the geometry and operating conditions. The company will be able to use the model for virtual prototyping of design changes. This will save time and money in moving toward improved designs that are needed for full scale production.