Coupled characterization and experimental verification of heat transfer and air leakage in a quad-sectional rotary air preheater

Abstract

Air leakage has a substantial impact on the efficiency of rotary air preheater, and is closely related to their temperature distribution. In this paper, for a quad-sectional rotary air preheater, the coupled model of thermodynamics and air leakage is proposed and verified by the experimental results of a double reheat 1000 MW power generator unit. The air leakage of each chamber, the temperature distribution of the fluid and the matrix can be obtained by using the three-dimensional finite-difference method. On the basis of previous research, the indirect air leakage is considered in the coupled model, as well as the interaction between the heat transfer and the air leakage. The simulation results show that the total air leakage of the quad-sectional air preheater is 33.1% less than that under the tri-sectional preheater condition. Additionally, compared with the experimental results, the difference values of the air leakage rates and the maximum duct outlet temperature are 0.21% and 2.1 °C, respectively, which manifest the model accuracy. The results indicate that, in comparison to previous research methods, this model can accurately obtain the temperature distribution of air preheater.