【作者】 崔小朝；

【导师】 刘才； 史荣；

【作者基本信息】 燕山大学 ， 机械设计及理论， 2001， 博士

【摘要】 高效连铸技术是近年来世界各国钢铁企业竟相追求的目标。随着连铸速度的提高，通过浸入水口注入结晶器的钢水流速和流量都显著增加，如果控制不当就会造成弯月面处液面波动剧烈、冲击深度加深、夹杂物气泡不易上浮、卷渣、裂纹、凝固壳厚度不一、中心组织疏松等缺陷。液态金属通过浸入式水口从中间包到结晶器，本身具有很大的流动动能，目前人们利用电磁制动技术降低这部分能量，减轻冲击深度，控制钢液的流动状态。作者通过仔细研究发现，只要依靠浸入式水口内腔结构形状、出口倾角、浸入深度以及浇注速度就可以使方坯连铸结晶器内钢水为旋转的涡流流动，把液态金属的流动动能利用起来。在对结晶器内钢水流场、温度场数值分析和水模型试验研究的基础上，提出一种全新的搅拌原理——依靠钢水本身具有的流动动能驱动结晶器内的钢水自旋转搅拌原理，为钢铁冶金企业提供一种独特的X形浸入式水口，取代方坯连铸结晶器内电磁制动和电磁搅拌，极大地减少设备投资，节省能耗。 连铸过程伴随着液态金属的流动、凝固传热、相态变化等。处理该问题的复杂性表现在必须同时处理包括质量、动量、能量方程以及湍流模式在内的一组方程，它们之间的耦合可以通过对流项、源项和热物性参数等发生。本论文应用SIMPLE法（Semi-Implicit Method for Pressure-Linked Equations），即求解压力耦合方程的半隐式法，开发了连铸过程液固温耦合数值模拟软件。应用该软件对方坯连铸钢液的流动状态、凝固规律和温度场进行耦合数值分析，对浇注方式、拉坯速度、浇注温度以及搅拌范围对温度场和流场的影响进行了深入研究，为防止连铸缺陷的产生提供对策。通过自旋转搅拌和电磁搅拌数值模拟，证明自旋转搅拌更有利于控制钢水的流动状态。 由于异形坯连铸形状本身的复杂性，带来钢液流动、凝固传热和温度场分布的复杂性。目前关于异形坯连铸的研究集中在设备和现场操作方面。利用所开发的液固温耦合数值模拟程序，考察浸入式水口倾角、浸入深度、浇注速度、浇注温度、浸入式水口个数和形式对异形坯连铸钢液流动方式和凝固传热的影响，为异型坯连铸的工艺设计、浸入式水口设计及流场控施提供了重要依据。 物理模拟不仅可以克服问题的复杂性、高温及测试手段的限制，而且可以验证数值模拟结果，完善数学模型。本论文采用二十世纪八十年代发展起来的PIV（Particle Image Velocimetry）技术就结晶器内钢水自旋转搅拌的流动状态和速度场分布进行了水模型物理模拟，与数值模拟结果基本一致。 连铸坯的质量一直是钢铁企业最为关注的问题。本论文就方坯连铸X形浸入式水口和漏斗形浸入式水口浇注时，连铸坯的表面质量、低倍组织、高倍组 O 燕山大学工学博士学位论文 一 织、力学性能和断口形貌进行了对比分析，结果发现X形浸入式水口浇注能改 善铸坯内外部质量、减少铸坯缺陷。与结晶器电磁搅拌相比，由于X形浸入式 水口所产生的自旋转搅拌是由内向外搅拌，不会产生负偏析，而且能达到电磁 搅拌同样的效果，可以有效地降低设备投资。更多还原

【Abstract】 High active continuous casting has become the target being chased by one other in steel occupation in the most country of the world recently. With the increase of continuous casting speed, more dramatic enhance has been acquired in liquid steel speed and flux though model of SEN water pouring. If it-be controlled incorrectly maybe it can caused strenuous fluctuate on meniscus deepen in impact depth. uneasy rising above of air bubble in occlusions cinder~ crackle~ thickness disparity of freezing shell~ rarefaction of central structure etc. The liquid metal contain many of kinetic energy when overflow the model from midst through SEN. Usually people used electromagnetic braking to reduce this parts of energy to alleviate impact depth. control the flow state of molten steel. Through survey carefully, we find that if depend on pouring ve1ocity~ structural shape of SEN entocoele~ angle slope of outlet depth of infusion together to make the liquid steel in model revolution in an order flow then it can utilize this kind of energy completely. This paper ,under the base of experimental investigation on watering modal and the numeric analysis of flow field ?temperature field in model, present a new theory of stirring ,namely, depend on the flowing energy which the liquid steel hold can implement it抯 rotation and afford a kind of unique X type SEN to replace electromagnetism stir and electromagnetism braking in model ,thus it can save a lot of energy and much money in equipment investment. 慦ith the process of continuous casting company the flow of liquid steel. the heat transfer in freezing~ the change of phase state. The complexity to solve this question is we must settle a equations set which include the equation about quality. momentum~ energy and turbulent current, and the coupling among them can be occurred through convection item source item and nature parameter of thermo physics.This paper adopt SIMPLE method(namely Semi-Implicit Method for Pr~ssure-Linked Equations) to exploit a coupled numeric analysis program for coupling among liquid~ solid-, temperature when continuous casting, by use this program proceed the coupled numeric analysis on temperature field and freezing rule ~flowing state about continuous casting liquid steel state for square and allotype billet, then it can supply a method to prevent the continuous cast deficiency. It can be approved that it is easier to curb the flow state by use rotation than use electromagnetic stir through the numerical simulation. For the complexity of the shape of allotype billet, flowage of liquid steel, heat transfer of freezing and distribution of temperature field also become complex. Presently most investigation of allotype billet focus on the equipment and fieldwork. By use this program to inve~tigate the effect of the declination of submerge nozzle, 桰II? W I~M眫Li~ submerge depth, pouring speed, pouring temperature and the number of submerge nozzle exert on liquid steel flowing mode in continuous casting of allotype billet, which afford an very important references for technological design of allotype billet continuous cast, design of submerge nozzle and the control of flow field. Physical simulation can overcame not only the complexity of questions~ high temperature and limitation of testing facility but also can testify the numerical simulation results then perfect the mathematic model. The paper adopt PIV (Particle Im更多还原