基于格子Boltzmann方法的微通道受热表面析晶污垢模拟

Lattice Boltzmann Simulation of Crystallization Fouling on Microchannel Heated Surface

针对现有的污垢析晶沉积模型不能有效模拟真实污垢生长的问题,建立了一种引入析晶沉积动力学模型的多物理场耦合数值模型。模型基于格子Boltzmann方法和有限差分方法,模拟了微通道非等温热表面上近壁面处的沉积物溶质质量浓度分布和污垢生长过程,研究了流速、壁温和沉积物溶质质量浓度对微通道热表面污垢析晶沉积的影响。结果表明:沉积初始时刻流速和壁温对近壁面沉积物溶质质量浓度分布具有不同程度的影响,随着污垢不断生长,污垢-流体界面处的析晶沉积速率减小;相比于流速,沉积物溶质质量浓度对污垢热阻的影响更为显著。

Aiming at the problem that the existing fouling crystallization deposition model cannot effectively simulate the real fouling growth, a mathematical model coupling with multi-physical fields that embedded the crystallization deposition dynamics model was established. Based on lattice Boltzmann method and finite difference method, the near-wall mass concentration distribution of the deposition solute and fouling growth process on the non-isothermal heated surface of microchannel were simulated. The effects of flow velocity, wall temperature and mass concentration of the deposition solute on fouling crystallization deposition on microchannel heated surface were studied. The results show that the flow velocity and wall temperature have different effects on the mass concentration distribution of the deposition solute near the wall at the initial deposition time. As the fouling keeps growing, the crystallization deposition rate on the fouling-fluid interface decreases gradually. The effect of mass concentration of the deposition solute on fouling thermal resistance is more significant than flow rate.