转—静盘腔系统的流动与换热特性数值研究

【作者】 冶萍；

【导师】 张靖周；

【作者基本信息】 南京航空航天大学 ， 工程热物理， 2004， 硕士

【摘要】 本文采用FLUENT商用软件，对二维和三维转-静盘腔的流动和传热过程进行了数值模拟研究。计算域包括转-静盘和内、外围屏包围的流体域以及一定厚度的转盘固体域。 论文主要工作和结果如下： (1)针对典型的转-静盘腔模型进行数值研究，通过对单方程模型、高k-ε模型和RNG k-ε模型获得的计算结果进行比较以及与相关试验数据验证，结果表明，RNG k-ε模型较高k-ε模型和单方程模型更能准确地模拟转静盘腔的流动。 (2)针对一典型的径向、轴向进气，径向出气的转-静盘腔结构，系统研究轴向进气位置、径向出口大小、旋转雷诺数、无量纲质量流量和轴向垂直／预旋进气等对盘腔内流动和换热的影响，整理出转-静盘腔内转盘平均努谢尔数与旋转雷诺数／无量纲质量流量之间的准则关联式。结果表明，高位轴向进气对转盘换热有利；不同的径向出口大小对盘腔内的流动换热影响不大；随旋转雷诺数和无量纲质量流量增加，转盘盘面的换热效果增强。 (3)自编用户程序模块，研究在轴向入流、径向出流的转-静盘腔中，无量纲流量随时间呈阶梯型改变对盘腔流动和换热的影响。当流量从某个稳定状态改变时，转盘上的平均努谢尔数会产生一个明显的上升再降低过程；在每一次流量改变的初始阶段，平均努谢尔数存在一个较大幅度的变化。 (4)建立有离散的预旋喷嘴和叶片冷却孔的预旋转-静盘腔的物理模型，研究预旋角θ=15°，30°，60°对盘腔流动和换热的影响，以及改变流动参数等对转盘盘面换热的影响，并总结出转盘平均努谢尔数与旋转雷诺数／无量纲质量流量之间的准则关联式。结果表明，预旋进气的优点在于增强了叶片冷却孔附近的对流换热效果，局部努谢尔数随预旋角的增大而有所减小；随旋转雷诺数的增加，不论是内转静腔室还是预旋腔室的静盘上的温度都不同程度的降低：当轴向中心进气质量流量不变时，随预旋进气的质量流量增加，内转静腔室的转盘盘面上的换热基本没有变化，而预旋腔室的转盘盘面上的换热效果增强；当预旋进气质量流量不变时，轴向中心进气的质量流量的改变对整个盘腔都有影响。更多还原

【Abstract】 Two- and Three-dimensional flow and heat transfer processes inside rotator-stator cavities were numerically studied using FLUENT-CFD software . The computational region was composed of fluid region enclosed by stator and rotator disks,as well as inner and outer shrouds, and solid region ,that is rotator disk.The main research work and results are the following:1) Numerical study was conducted for the flow problem inside a typical rotator-stator cavities with different turbulent models including 1-equation model and high k - model RNG k - model. By comparing the results with relative experiment data, it is shown that RNG k - is more exactly than the other turbulent model..2) The influences of axial inflow position, radial outflow size, rotating Reynold number, non-dimensional mass flowrate and axial inflow angle on the flow and heat transfer characteristics were numerically investigated for a typical rotator-stator cavity with axial inflow, radial inflow and radial outflow . The correlations for Average Nusselt number vs rotating Reynold number or non-dimensional mass flowrate were established. The results indicate that: The high positioned air inflow do good to heat transfer in rotator disk; different size of radial outflow have small effects on flow and heat transfer; the heat transfer near rotating disk increases as rotating Reynold number increases or non-dimensional mass flow rate increases.3) A custom filed function module was complied to study the influence of non-dimensional mass flowrate changed with time in stair shape on flow and heat transfer inside rotator-stator cavity with axial inflow and radial outflow .Average Nusselt number takes on a sharp up-down process when the mass flowrate changes from stabile status as to the following change of flowrate, the average Nuselt number changes greatly in the initial stage and then changes gradually.4) In a pre-swirl rotator-stator cavities with discrete pre-swirl nozzles and blade-cooling entry holes, the influences of pre-swirl angle and flow parameter on the flow and heat transfer characteristics were numerically investigated. The correlation for Average Nusselt number vs rotating Reynold number or non-dimensional mass flowrate were established. The results show that: advantage of per-swirl inflow is the effect of cooling the blade-cooling entry holes; pre-swirl inflow increases heat transfer in rotating disk of pre-swirl chamber; as pre-swirl angle increases,local Nusselt number decreases in pre-swirl chamber; the temperature of stator of inner rotator-stator chamber and per-swirl chamber decreases as rotating Reynold number increases; when the axial mass flowrate maintains constant, heat transfer in the rotating disk of inner rotator-stator cavities doesn’t change as per-swirl mass flowrate increases, while heat transfer in the rotating disk of per-swirl chamber increases; when the pre-swirl mass flowrate maintains constant ,change of the axial mass flowrate has effect on the whole cavity.更多还原