角度-空间间断谱元法的遮蔽条件下二维热辐射特性研究

Angle-Space Discontinuous Spectral Element Method for Two-Dimensional Thermal Radiation Heat Transfer Within Shadowing Boundary Condition

关键词:  燃烧室  热辐射  辐射遮蔽  角度-空间间断谱元法  黎曼迎风方案

Key words:  Combustor  Thermal radiation  Radiation shielding  Angle-space discontinuous spectral element method  Riemann up-wind system

摘要:

航空发动机燃烧室温度分布对燃烧室结构设计、燃烧过程检测均具有重要意义。燃烧室结构封闭且复杂、存在大面积的辐射遮挡，这给计算其内部由热辐射引起的温度变化分析带来了一定困难。本文提出采用角度-空间间断谱元法求解遮蔽条件下封闭腔内热辐射问题。在求解过程中，通过黎曼迎风方案对空间单元边界上的辐射信息进行分割，实现单元间信息的有效传递。通过与文献结果进行对比发现：角度上采用间断谱元法可有效抑制辐射遮蔽带来的数值振荡，相同角度离散单元数下，可以获得比离散坐标法更光滑的计算结果。通过分析网格数和基函数阶数对数值结果的影响，发现该方法具有hp收敛特性。此外，控制角度计算节点相同，在与离散坐标法相当的计算精度下，消耗更少的计算时间。

Abstract:

The temperature distribution of aero-engine combustor is very important for the structural design and combustion process detection of aero-engine combustor. The combustor structure is closed and complex， and there is a large area of radiation shielding， which bring some difficulties to the calculation of temperature change caused by thermal radiation. An angle-space discontinuous spectral element method is proposed to solve the thermal radiation problem in a closed cavity under shielding conditions. In the solving process， the radiation information on the space element boundary is segmented by Riemann upwind scheme to achieve effective information transfer between elements. Compared with the results in the literature， with same angular elements， it is found that the discontinuous spectral element method can effectively suppress the numerical oscillation caused by radiation shielding and obtain smoother results than the discrete coordinate method. By analyzing the influence of element numbers and the order of basis function on numerical results， this method has hp convergence characteristics. In addition， control angle calculation nodes are same， which spends less calculation time under the same calculation precision with discrete coordinate method.