Numerical Study on the Effect of Wheel Aerator Paddle Profiles to Fluid Flow Characteristics and Aeration Performance Prediction

Water quality plays an essential role in the success of aquaculture in fishery industries. The quality relies on the substance’s level in the water and one of the substances is dissolved oxygen level. Most cases in modern fishery farms, the farmers use artificial aerators to maintain dissolved oxygen as required. Therefore, dissolved oxygen levels in water are strongly related to the design of the artificial aerator to be used in a fish farming system. One type of artificial aerator available in the market is a paddle wheel or water wheel. The paddle offered in the market is designed with several models. Farmers should select a suitable paddle for their pond to get maximum aeration. However, the selection is challenging as farmers have no reference for a suitable paddle for aerating the pond. The paper aims to analyze the influence of the wheel aerator paddle design/profile on the flow characteristics of the water. The flow affects aeration of water and eventually the dissolved oxygen. In this study, two different paddle profile models are numerically observed. Both models are developed and evaluated using the CFD (Computational Fluid Dynamics) method. The models are evaluated using OpenFOAM software. From the simulation results, the paddle B profile which has larger surface area with greater number of holes is expected to give a higher level of dissolved oxygen to the water rather than the paddle A (smaller one). That is because the bigger paddle produces a higher fluid velocity (48m/s compared to 22 m/s at paddle A) and has a higher turbulence intensity level (17.3% compared to 7.4% of paddle A), so it is likely to produce a stronger mixing effect. The size and numbers of the hole give important effect to the aerating process. The smaller the hole and the larger number of holes provide strong circulation thus the flow regime is more chaotic which gives better aeration.