Abstract

One of the major problems of rotary air preheaters (RAPHs) is leakage which has a direct impact on its performance reduction. The purpose of this study is to examine the behavior of different types of leakage in the RAPH and its effects on the performance of overall heat transfer. A real power plant was modeled and simulated using three-dimensional numerical approach. The details found by 3D simulation would give a better understanding of the flow behavior in the RAPH which is very important in the design and maintenance stages of each RAPH. The flow pattern and temperature distribution in clearance spaces of four radial wings and axial sector plates were investigated along with the temperature distribution of the matrix. The results revealed that radial leakage in the hot end had a more negative effect on the performance of RAPH, since in this end, both thermal energy and mass flow of air are wasted together. The effects of each leakage at different clearances were compared and the changes in air and flue gas outlet temperatures due to leakage were discussed. The results were validated with experimental data.

摘要

回转式空气预热器 (RAPH) 的主要问题之一是泄漏，这直接影响其性能下降。本研究的目的是检查 RAPH 中不同类型泄漏的行为及其对整体传热性能的影响。使用三维数值方法对真实发电厂进行建模和模拟。通过 3D 模拟发现的细节可以更好地理解 RAPH 中的流动行为，这在每个 RAPH 的设计和维护阶段非常重要。研究了四个径向翼和轴向扇形板间隙空间的流动模式和温度分布以及基体的温度分布。结果表明，热端径向泄漏对 RAPH 性能的负面影响更大，因为为此，热能和空气质量流量都被浪费了。比较了不同间隙下每次泄漏的影响，讨论了泄漏引起的空气和烟气出口温度的变化。用实验数据验证了结果。