卷渣会降低钢锭产品质量,研究钢锭浇注过程的卷渣行为对提升钢锭产品质量具有重要意义。本研究以9 t八角锭为研究对象,建立了VOF(Volume of Fluid)多相流模型,系统分析不同浇注速度下钢液充型流场特征、韦伯数变化、液面波动以及钢-渣界面行为。研究结果表明,20 kg/s为该铸锭发生卷渣的临界最大浇注速度,低于该速度时,中心流股附近韦伯数小于临界韦伯数,钢液充型流场稳定,液面波动平缓,中心波高为0.06 m,钢-渣界面稳定且无卷渣发生;高于此速度时,中心流股附近韦伯数超过临界值,流场稳定性下降,中心流股高度及湍动能增加,中心波高增至0.08 m,渣眼停留时间延长,导致钢-渣界面失稳,液面波动加剧,钢液中残余渣相含量显著上升,残留率由15 kg/s时的0%激增为25 kg/s时的74.3%。
Abstract
Slag entrainment compromises ingot quality. Investigating its behaviour during ingot casting is crucial for enhancing product quality. In this study, a 9 t octagonal ingot was selected as the research object and a VOF(Volume of Fluid) multiphase flow model was established to systematically analyze the behaviour of molten steel filling flow fields, variations in Weber number, liquid surface fluctuations, and steel-slag interface behavior under different casting speeds. The results show that a casting speed of 20 kg/s represents the critical maximum casting speed at which slag entrainment occurs in this ingot. Below this speed, the Weber number near the central flow stream remains lower than the critical value, indicating stable flow patterns and mild surface fluctuations, with a central wave height of 0.06 m. The steel-slag interface remains stable, and slag entrainment does not occur. When the casting speed exceeds this threshold, the Weber number near the central flow stream exceeds the critical value, reducing flow stability. The height of the central surface hump and the turbulent kinetic energy of the central jet increase, raising the central wave height to about 0.08 m. The residence time of slag eye becomes longer, intensifying surface fluctuations and destabilizing the steel-slag interface. Consequently, the residual slag phase content in the molten steel increases sharply, with the residual rate rising from 0% at 15 kg/s to 74.3% at 25 kg/s.
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