基于自模化理论的烟气流速测点布置方式研究

Study on Arrangement of Flue Gas Velocity Measuring Points Based on Self-modeling Theory

研究并分析了大型燃煤电厂脱硫后至烟囱进口部分的带有90°弯的尾部烟道内烟气流动状况和流动特性,利用黏性流体自模化区的理论和中值定理,分析出不同进口流速下尾部烟道内存在能够代表进口处烟气流速的区域。通过对距离烟囱进口不同截面上二次流流线对比分析,找到流线分布均匀、无二次流且与烟囱进口距离合适的截面,通过分析对比该截面上的等速线分布情况找到合适的测点布置方案。结果表明:该测点布置方案可以极大地减少带有90°弯的大型尾部烟道的测点布置数量并提高测量的精确度。

The flow conditions and characteristics of the flue gas in the tail flue with a 90°bend,which was installed between the desulfurizer and the chimney inlet,were investigated.Based on the theory of self-mode region of viscous fluid and the mean value theorem,the regions in the tail flue that represent the enterance velocity of flue gas at different inlet velocity were analyzed.By the comparation of secondary flow lines between different sections from the chimney inlet,the section with uniform distribution of flow lines,no secondary flow and appropriate distance from the chimney inlet was located.Furthermore,the optimal arrangement of measuring points was determined by the analyses and comparations of isovelocities distribution on this section.Results show that the number of measuring points arrangement for the large tail flue with a 90°bend is greatly reduced by the utilization of the measuring points arrangement proposed and the measuring accuracy is improved.