Numerical study is performed for the flow and heat transfer characteristics of flue gas side of a fluoroplastic steel air preheater with elliptical tubes. The influence laws of ellipticity

horizontal and longitudinal relative pitch

internal and external fluorine plastic film thickness and air film thickness on heat transfer and resistance are analyzed and summarized. The results show that

with an increase in the ellipticity

the mean convective heat transfer coefficient and resistance increase gradually while the heat transfer rate per unit fan power decreases gradually. Increasing the longitudinal relative pitch and decreasing the transverse relative pitch will increase the mean convective heat transfer coefficient and pressure drop

which is not conducive to the improvement of the comprehensive performance of the elliptical tube air preheater. The increase of internal and external fluorine plastic film thickness will lead to the decrease of heat transfer

but the inner fluorine plastic film has a greater effect on the heat transfer performance. The heat transfer decreases rapidly with the increase of the air film thickness. The heat transfer decreases by 33.1% with the air film thickness of 0.1 mm only. The technical level of fluorine plastic film covering is an important factor affecting the application of the elliptical tube fluorine plastic steel air preheater.