偏心底吹氩钢锭流场及混合特性数值模拟

Numerical simulation of flow field and mixing characteristics in steel ingot with eccentric bottom blowing argon

针对钢锭模内钢液流场及混匀特性,提出钢锭偏心底吹工艺,以某厂40 t钢锭为研究对象,采用Fluent软件研究了底吹流量、底吹位置对锭模内钢液流场及混合特性的影响规律。结果表明,偏心底吹氩钢锭内形成非对称循环流,气-液两相流在到达冒口区之前,两相区在径向不断扩大;其到达冒口区后,两相区变小。当底吹气量(氩气流量)小于40 L/min时,锭模内尚未形成明显的完整循环流;当气量增至60 L/min时,锭模内才形成完整循环流。整体上,混匀时间随气量增加呈减小趋势,但存在一个最佳混匀气量;随着底吹位置距锭底中心距离增加,混匀时间呈减小趋势。根据本研究,最佳的混匀底吹位置为距锭底中心1/2半径处。

According to the flow field and mixing characteristics of molten steel in ingot mould, the eccentric bottom blowing process of ingot was proposed, the Fluent software was used to study the influence of blowing argon flow rate and bottom blowing position on the flow field and mixing characteristics of molten steel in a 40 t steel ingot. The result shows that non-symmetric circulating flow is formed in the eccentric bottom-blown argon steel ingot. The two-phase region continuously expands in the radial direction before the gas-liquid two-phase flow reaches the riser zone, while after it reaches the riser zone, the two-phase region becomes smaller. When the bottom blowing flow rate(argon flow rate) is less than 40 L/min, no obvious complete circulating flow is formed in the ingot mould. A complete circulating flow is formed until the bottom blowing flow rate increases to 60 L/min. As a whole, the mixing time decreases with the increase of blowing argon flow rate, but the mixing flow has an optimum value. As the distance between bottom blowing position and the bottom center of ingot increases, the mixing time decreases. In this work, the optimum bottom blowing position is the position at a half of steel ingot radius.