A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace （TTRHF） in compact strip production （CSP）. To accurately predict the heat exchange...A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace （TTRHF） in compact strip production （CSP）. To accurately predict the heat exchange in the furnace, modeling of the complex gas energy-balance equation in volume zones was considered, and the heat transfer model of heating slabs and wall lines was coupled with the radiative heat transfer model to identify the surface zonal temperature. With numerical simulation, the temperature fields of gas, slabs, and wall lines in the furnace under one typical working condition were carefully accounted and analyzed. The fundamental theory for analyzing the thermal process in TI＇RI-IF was provided.展开更多
When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was pro...When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was pro- posed, which employed imaginary planes, referred to as the imaginary plane model. With the new model, crown wall reduction process was simplified. Therefore, every model zone could be treated as a closed square cavity. It could also solve the problem of radiative blocking in industrial furnaces more effectively. Besides, the new imaginary plane based model may lead to a problem that the denominator was zero. This problem was solved by transforming the ex- pressions of reflex heat flux in the model. The model was capable of dealing with the systems that included black sur- faces. The model was validated by considering the heat transfer in a reheating furnace where the temperature fields in the furnace chamber （including the steel, wall and gas） were obtained. A detailed comparison was made between the simulation and the black box experiment. The results show that the new model developed was valid and accurate.展开更多
A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and...A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and solved by a three stage explicit time stepping scheme in each block with some extra treatments of interface at each step. The predicted aerodynamic coefficients and vortical flow field are reasonable.展开更多
On the basis of the quasi-geostrophic vorticity equation,theoretical research has been down upon the evolution of the amplitude of solitary Rossby waves employing the perturbation method,and come to the conclusion tha...On the basis of the quasi-geostrophic vorticity equation,theoretical research has been down upon the evolution of the amplitude of solitary Rossby waves employing the perturbation method,and come to the conclusion that the evolution of the amplitude satisfies the variable coefficient Korteweg-de Vries(KdV) equation.展开更多
介绍一种全新的数值方法——分区有限线法(zonal finite line method,ZFLM),并将其应用于求解复合结构中的热应力问题.ZFLM是一种配点型的强形式算法,对于每个配置点,由过其的两条(二维问题)或三条(三维问题)线段建立一个交叉线系,采用...介绍一种全新的数值方法——分区有限线法(zonal finite line method,ZFLM),并将其应用于求解复合结构中的热应力问题.ZFLM是一种配点型的强形式算法,对于每个配置点,由过其的两条(二维问题)或三条(三维问题)线段建立一个交叉线系,采用拉格朗日插值多项式对每条线段的坐标与物理量进行函数表征,并用沿弧长方向求导法创建任意物理量对总体坐标的一阶偏导数解析计算式,通过递推技术,由一阶偏导数公式建立二阶偏导数计算式.采用建立的偏导数计算式,可直接由问题的控制微分方程及其边界条件建立离散的总体系统方程组.为了建立高效的有限线法和能够求解复杂的由多种材料组成的复合结构问题,提出一种分区计算方法,即:根据材料的不同或几何与载荷的不规则性,将所分析的问题划分为若干个结构化计算区域,在每个区域由插值函数自动产生一系列配置点,并用有限线法建立每个配置点的离散方程.对于区域间的公共节点,由物理量的协调条件以及界面力的平衡条件建立界面节点代数方程;对于几何不规则或载荷跳跃问题,采用面力方程叠加法建立非规则节点的代数方程,以提高计算结果的稳定性.采用本文方法对二维/三维结构的热应力进行分析.计算结果表明本文方法具有很好的精度,且在边界上的应力更为精确,应力集中的效果更为明显.展开更多
采用由两方程k-ω模式推导得到的k-g模式数值模拟完整飞机构形的跨声速大迎角流场。由于k-g模式具有勿需使用到物面的法向距离、简单的源项和直接的边界条件等特点,可以方便地推广到包含复杂外形的多块网格系统。与雷诺平均N av ier-S t...采用由两方程k-ω模式推导得到的k-g模式数值模拟完整飞机构形的跨声速大迎角流场。由于k-g模式具有勿需使用到物面的法向距离、简单的源项和直接的边界条件等特点,可以方便地推广到包含复杂外形的多块网格系统。与雷诺平均N av ier-S tokes方程组的求解方法类似,k-g模式方程也采用显式R unge-K u tta方法进行时间推进,用中心加人工粘性格式进行空间离散。采用相同的方法数值模拟NA SA TN D-712翼身组合体标模迎角为12.5°和26.2°的流场来检验程序的可靠性,与可获得的实验数据进行对比分析并获得满意结果。与此同时,还使用了B a ldw in-Lom ax代数模式以作比较。展开更多
文摘A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace （TTRHF） in compact strip production （CSP）. To accurately predict the heat exchange in the furnace, modeling of the complex gas energy-balance equation in volume zones was considered, and the heat transfer model of heating slabs and wall lines was coupled with the radiative heat transfer model to identify the surface zonal temperature. With numerical simulation, the temperature fields of gas, slabs, and wall lines in the furnace under one typical working condition were carefully accounted and analyzed. The fundamental theory for analyzing the thermal process in TI＇RI-IF was provided.
基金Item Sponsored by National High Technology Research and Development Program(863Program)of China(2011AA060104)
文摘When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was pro- posed, which employed imaginary planes, referred to as the imaginary plane model. With the new model, crown wall reduction process was simplified. Therefore, every model zone could be treated as a closed square cavity. It could also solve the problem of radiative blocking in industrial furnaces more effectively. Besides, the new imaginary plane based model may lead to a problem that the denominator was zero. This problem was solved by transforming the ex- pressions of reflex heat flux in the model. The model was capable of dealing with the systems that included black sur- faces. The model was validated by considering the heat transfer in a reheating furnace where the temperature fields in the furnace chamber （including the steel, wall and gas） were obtained. A detailed comparison was made between the simulation and the black box experiment. The results show that the new model developed was valid and accurate.
文摘A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and solved by a three stage explicit time stepping scheme in each block with some extra treatments of interface at each step. The predicted aerodynamic coefficients and vortical flow field are reasonable.
基金supported by the Meteorological Special Project of China(GYHY200806005)the National Natural Sciences Foundation of China(40805028,40675039,40575036)the Key Technologies R&D Program of China(2009BAC51B04)
文摘On the basis of the quasi-geostrophic vorticity equation,theoretical research has been down upon the evolution of the amplitude of solitary Rossby waves employing the perturbation method,and come to the conclusion that the evolution of the amplitude satisfies the variable coefficient Korteweg-de Vries(KdV) equation.
文摘介绍一种全新的数值方法——分区有限线法(zonal finite line method,ZFLM),并将其应用于求解复合结构中的热应力问题.ZFLM是一种配点型的强形式算法,对于每个配置点,由过其的两条(二维问题)或三条(三维问题)线段建立一个交叉线系,采用拉格朗日插值多项式对每条线段的坐标与物理量进行函数表征,并用沿弧长方向求导法创建任意物理量对总体坐标的一阶偏导数解析计算式,通过递推技术,由一阶偏导数公式建立二阶偏导数计算式.采用建立的偏导数计算式,可直接由问题的控制微分方程及其边界条件建立离散的总体系统方程组.为了建立高效的有限线法和能够求解复杂的由多种材料组成的复合结构问题,提出一种分区计算方法,即:根据材料的不同或几何与载荷的不规则性,将所分析的问题划分为若干个结构化计算区域,在每个区域由插值函数自动产生一系列配置点,并用有限线法建立每个配置点的离散方程.对于区域间的公共节点,由物理量的协调条件以及界面力的平衡条件建立界面节点代数方程;对于几何不规则或载荷跳跃问题,采用面力方程叠加法建立非规则节点的代数方程,以提高计算结果的稳定性.采用本文方法对二维/三维结构的热应力进行分析.计算结果表明本文方法具有很好的精度,且在边界上的应力更为精确,应力集中的效果更为明显.
文摘采用由两方程k-ω模式推导得到的k-g模式数值模拟完整飞机构形的跨声速大迎角流场。由于k-g模式具有勿需使用到物面的法向距离、简单的源项和直接的边界条件等特点,可以方便地推广到包含复杂外形的多块网格系统。与雷诺平均N av ier-S tokes方程组的求解方法类似,k-g模式方程也采用显式R unge-K u tta方法进行时间推进,用中心加人工粘性格式进行空间离散。采用相同的方法数值模拟NA SA TN D-712翼身组合体标模迎角为12.5°和26.2°的流场来检验程序的可靠性,与可获得的实验数据进行对比分析并获得满意结果。与此同时,还使用了B a ldw in-Lom ax代数模式以作比较。
