This research focuses on performing multiphase solid/liquid/gas CFD simulations of a UASB reactor in order to obtain a validated model that provides a clearer understanding of the hydrodynamic behaviour of the three phases in UASB reactors. Eulerian–Eulerian, laminar, three-dimensional, multiphase simulations are carried out using Fluent 16.2. The liquid phase velocity and flow profile are validated through PIV experiments. A liquid mean velocity difference of 8.45% is found between the experimental and numerical results, thus validating the CFD model. Shadowgraphy is applied successfully to validate the biogas phase velocity and bubble size. Based on the hydrodynamic analysis results, the reactor can be divided into four regions, according to its mixing conditions. For the flow rates studied, minimal solids washout is observed. In the present research, only 0.02% of the volume are dead zones within the reactor, which indicates good mixing conditions. The reactor shows a recirculation stream at the centre that has an important role in relation to the mixing conditions. The validated model can be used for further studies on the optimisation of UASB reactors.

这项研究的重点是对UASB反应器进行多相固/液/气CFD模拟，以便获得经过验证的模型，从而可以更清楚地了解UASB反应器中三相的水动力行为。使用Fluent 16.2进行欧拉-欧拉，层流，三维多相模拟。通过PIV实验验证了液相速度和流动曲线。实验和数值结果之间发现液体平均速度差为8.45％，从而验证了CFD模型。皮影术已成功应用于验证沼气相速度和气泡大小。根据流体动力学分析结果，根据反应器的混合条件，可将其分为四个区域。对于研究的流速，观察到最小的固体冲刷。在本研究中，只有0.02％的体积是反应器内的死区，这表明良好的混合条件。反应器在中心处显示再循环流，该再循环流对于混合条件具有重要作用。验证的模型可用于进一步研究UASB反应器的优化。