基于气泡数密度模型的气体穿越液池过程气泡特性数值模拟

摘要

An average bubble number density (ABND) transport equation considering bubbles breakup and coalescence was merged with the Euler-Euler turbulence two-fluid model in the Computational Fluid Dynamics (CFD) to establish the CFD-ABND coupling model which was used to study the bubble size distribution and the interfacial area concentration (IAC) distribution in the pool when the gas-solid flow passed through the pool. The quantitative results of bubbles size and IAC distribution were observed, and the influence of gas velocity on the distribution of the bubble and the IAC was analyzed. It was found that the present model had a better performance for predicting the bubble size and IAC distribution. The results showed that the larger bubble and the higher IAC mainly existed near the exit and outer wall of the cooling tube. The separator inserter IAC in the pool was very helpful to strengthen the disturbance between gas and liquid, which could effectively reduce the bubble size and increase the IAC.%采用考虑了气泡破碎和聚并的平均气泡数密度（ABND）输运方程，并与计算流体力学（CFD）中的湍流双流体模型相结合，建立 CFD-ABND 耦合计算模型。运用该模型对含固体颗粒气体通过冷却管穿越液池过程中液池内的气泡尺寸和气液界面浓度进行数值模拟。定量获得了液池内气泡尺寸和气液界面浓度分布，并分析了气速变化对其影响规律。结果表明：所建立的 CFD-ABND 模型能够对液池中的气泡尺寸及气液界面浓度分布等气泡特性进行较好预测；在靠近冷却管外壁面附近区域形成较大尺寸气泡和较高气液界面浓度；液池内隔板的存在有助于气液扰动，使液池内总体的气泡尺寸得到有效降低及气液界面浓度得到提升。