轧辊三维瞬态温度场的一种二维简化计算模型——400×1850铝板带冷轧机工作辊温度场与热变形数值模拟

【作者】 胡秋；

【导师】 肖刚；

【作者基本信息】 中南大学 ， 机械设计与理论， 2002， 硕士

【摘要】 轧辊的热变形直接影响着受轧带材板形质量，然而由于轧辊热力学现象的复杂性，求解工作辊的热变形是板形研究领域的薄弱环节，其研究方法也相对落后一些。 传统轴对称模型无法考虑轧辊周期性动边界问题，既不能准确地描述轧辊温度场和热变形的周期性变化规律，也无法分析并求出真正影响板形质量的轧辊出口热变形量，而采用三维瞬态温度场模型则存在计算量大，编程复杂的问题。为此本文在合理假设的基础上，把轧辊圆柱体某一瞬态的热行为近似描述为轧辊圆柱中某一特定子午面一个周期内热行为的时间累积，灵活地解决了以往只能在三维模型才能解决的轧辊周期性动边界问题。这样既克服了以往模型纯粹轴对称假设所带来的误差，也实现了工作辊三维瞬态温度场的二维简化，为轧辊温度场高精度高速度的仿真提供了可能性和前提。仿真结果既能反映出轧辊温度场和热变形的周期性变化规律，从而对轧辊“凸轮效应”有一个清晰的认识，同时也能反映出轧辊轴向温度场分布。 边界条件的处理是影响轧辊温度场求解精度的一个主要因素。为提高边界条件计算精度，本文引入预位移——滑动摩擦模型对轧制区摩擦热进行了较准确的计算。通过联立求解轧辊与轧件稳态热平衡方程，求得了轧件与轧辊之间接触导热系数和冷却液对流换热系数，从而建立了一种简单实用且比较接近轧制情况的热力学参数确定方法。 本文最后对国内某厂400×1850冷轧机轧辊温度场和热变形进行了仿真，仿真结果与实测数据有很好的一致性，从而验证了本文模型的正确性。其结果可以为板形控制和辊型原始配置提供基础。更多还原

【Abstract】 Strip profile and flatness, which are important measures of product quality, are critically affected by thermal deformation of work rolls, however because of the complexity of rolls’ thermodynamics phenomena, calculation of rolls’ thermal deformation was the weak links in the domain of shape control, and its’ research methods were behind relatively.Problem of periodical variable boundary condition was unsolvable in axially symmetric model of rolls’ temperature field in the past, so the periodical variation regularity of rolls’ temperature distribution and thermal deformation can not be described accurately, and the thermal deformation of the work rolls at the outlet, which affect the shape quality of strip directly, was unable to be analyzed and calculated. On the other hand, computation and programming were too complicate hi three-dimension transient model. In this paper, on the base of reasonable postulation, an arbitrary meridian plane of work rolls was taken as research object, transient heat action of work rolls was described approximately as the hot action accumulation of a certain meridian plane of the work rolls in a period, problem of periodical variable boundary was solved flexibly in two-dimension, which can been solved only in three-dimension temperature field model in the past. By this way, the error brought by pure axial symmetry model was surmounted, and three dimension transient temperature field was solved flexibly in two-dimension axially symmetric model, this makes it possible to numerically calculate the work rolls’ temperature field accurately and fast. Using the model of this paper, the results of the simulation rightly reflect the periodical variation regularity of rolls temperature, so the" cam effect" of work rolls was described distinctly, at the same time axial temperature field of rolls was reflected too. vThe treatment of boundary condition is an important factor, which influence the precision of temperature distribution within the work rolls directly. In order to improve the calculation accuracy of thermal boundary condition, friction heat was calculated accurately by preparatory displacement-slip friction model. By means of solving heat equilibrium equation of work rolls and workpiece, a simple practical method to calculate the thermodynamic parameter of the rolls’ temperature field was established.In the end, the temperature field and heat deformation of work rolls in 400^500 cold rolling mill was calculated, and the results were consistent with the measurement closely, thus the model of this paper has been verified, and it can provide base for the shape control and original disposition of work rolls.更多还原