底吹气连铸中间包内气液两相流的数值模拟

Numerical Simulation on Gas-Liquid Two Phase Flow in Continuous Casting Tundish with Bottom Gas Blowing

以宝钢集团梅山钢厂1台连铸中间包为原型,进行底吹气中间包水模型研究.实测结果表明,底吹气在中间包内形成“鼓泡流”形式的流动结构;“鼓泡流”的形成一方面能够破坏中间包内“层流”形式的短路流动,增强混合,另一方面能在中间包内形成“气幕挡墙”,有利于夹杂物去除.针对中间包内气?液两相“鼓泡流”特征,建立了底吹气中间包内气?液两相欧拉多流体模型,模型中考虑了气泡的存在对湍流增强的影响,考虑了相间滑移、气泡浮力及湍流分散力.采用所建立的模型对底吹气中间包内气液两相流动和混合特性进行了模拟和分析,结果与水模型实测结果一致.

Gas-liquid two phase flow in a tundish has been studied with a water model, prototype of which is the one in Meishan Iron and Steel Corporation. Experimental results show that with bottom gas blowing, tiny, steady and uniformly distributed bubbles can be produced and bubbly flow pattern forms in the tundish, uprising bubbly flow can destroy the laminar-like flow in the tundish and enhance flow mixing, on the other hand, the uprising bubbles can form a baffle-like gas column, which is in favor of inclusion removal. Based on the experiments, an Eulerian multi-fluid model is used to simulate gas?liquid bubbly flow in the tundish, Sato model is incorporated to include bubble-induced turbulence, Grace model is used to model inter-phase drag force, buoyancy is considered with Boussinesq approximation, turbulence dispersion force is also included with the model of Lopez. Numerical results well agree with those from experiments.