建立了描述FCC提升管中气-固流动行为的CFD-PBM耦合模型,模型同时考虑了颗粒动力学和颗粒聚并破碎内核。讨论了求解耦合模型中众体平衡方程(PBE)的3种典型矩方法[即:正交矩方法(quadrature method of moments,QMOM),直接正交矩方法(dire...建立了描述FCC提升管中气-固流动行为的CFD-PBM耦合模型,模型同时考虑了颗粒动力学和颗粒聚并破碎内核。讨论了求解耦合模型中众体平衡方程(PBE)的3种典型矩方法[即:正交矩方法(quadrature method of moments,QMOM),直接正交矩方法(direct quadrature method of moments,DQMOM)和固定轴点正交矩方法(fixed pivot quadrature method of moments,FPQMOM)]对模拟结果的影响。研究结果表明3种矩方法均能合理预测提升管内径向和轴向颗粒体积分数和颗粒速度分布。通过将模拟结果与实验结果进行比较,表明QMOM在反应器结构简单情况下,计算结果更接近于实际情况。展开更多
In the hydraulic transporting process of cutter-suction mining natural gas hydrate, when the temperature-pressure equilibrium of gas hydrate is broken, gas hydrates dissociate into gas. As a result, solid-liquid two-p...In the hydraulic transporting process of cutter-suction mining natural gas hydrate, when the temperature-pressure equilibrium of gas hydrate is broken, gas hydrates dissociate into gas. As a result, solid-liquid two-phase flow(hydrate and water) transforms into gas-solid-liquid three-phase flow(methane, hydrate and water) inside the pipeline. The Euler model and CFD-PBM model were used to simulate gas-solid-liquid three-phase flow. Numerical simulation results show that the gas and solid phase gradually accumulate to the center of the pipe. Flow velocity decreases from center to boundary of the pipe along the radial direction. Comparison of numerical simulation results of two models reveals that the flow state simulated by CFD-PBM model is more uniform than that simulated by Euler model, and the main behavior of the bubble is small bubbles coalescence to large one. Comparison of numerical simulation and experimental investigation shows that the values of flow velocity and gas fraction in CFD-PBM model agree with experimental data better than those in Euler model. The proposed PBM model provides a more accurate and effective way to estimate three-phase flow state of transporting gas hydrate within the submarine pipeline.展开更多
文摘建立了描述FCC提升管中气-固流动行为的CFD-PBM耦合模型,模型同时考虑了颗粒动力学和颗粒聚并破碎内核。讨论了求解耦合模型中众体平衡方程(PBE)的3种典型矩方法[即:正交矩方法(quadrature method of moments,QMOM),直接正交矩方法(direct quadrature method of moments,DQMOM)和固定轴点正交矩方法(fixed pivot quadrature method of moments,FPQMOM)]对模拟结果的影响。研究结果表明3种矩方法均能合理预测提升管内径向和轴向颗粒体积分数和颗粒速度分布。通过将模拟结果与实验结果进行比较,表明QMOM在反应器结构简单情况下,计算结果更接近于实际情况。
基金Project(51375498) supported by the National Natural Science Foundation of China
文摘In the hydraulic transporting process of cutter-suction mining natural gas hydrate, when the temperature-pressure equilibrium of gas hydrate is broken, gas hydrates dissociate into gas. As a result, solid-liquid two-phase flow(hydrate and water) transforms into gas-solid-liquid three-phase flow(methane, hydrate and water) inside the pipeline. The Euler model and CFD-PBM model were used to simulate gas-solid-liquid three-phase flow. Numerical simulation results show that the gas and solid phase gradually accumulate to the center of the pipe. Flow velocity decreases from center to boundary of the pipe along the radial direction. Comparison of numerical simulation results of two models reveals that the flow state simulated by CFD-PBM model is more uniform than that simulated by Euler model, and the main behavior of the bubble is small bubbles coalescence to large one. Comparison of numerical simulation and experimental investigation shows that the values of flow velocity and gas fraction in CFD-PBM model agree with experimental data better than those in Euler model. The proposed PBM model provides a more accurate and effective way to estimate three-phase flow state of transporting gas hydrate within the submarine pipeline.
