关键词: 乙烯燃气锅炉, 送风道, 剧烈振动, 噪音, 导流板, 卡门涡流, 防振隔板

Abstract:

During the commissioning stage of the newly installed ethylene gas boiler, abnormal vibration and noise appeared in the air supply duct when the opening of the air supply fan valve reached over 37%. As the opening of the air valve increased, the vibration of the air duct and abnormal noise increased. The causes of abnormal vibration in the air supply duct were analyzed from the aspects of fan surge, uneven distribution of air flow field and Karman vortex resonance. Measures such as enhancing stiffness of the air duct, adding support rods in the air duct, and increasing guide plates in the variable diameter duct at the outlet of the air supply fan were taken, but no obvious effect was received. Removing the air heater and adding guide plates at the inlet and outlet of the air preheater achieved a certain effect. When the opening of the air valve reached 49%, the duct vibration and noise significantly increased, but the duct vibration could not be effectively eliminated. After calculation, it was confirmed that the consistency between the air preheater Karman vortex frequency and the air chamber inherent frequency was the main cause of violent vibration and noise of the air supply duct. By changing the width of the air preheater pipe box, adding the anti-vibration plate in the pipe box, changing the inherent frequency of the air chamber, reducing the Karman vortex effect, the violent vibration and noise of the air duct were eradicated.

Key words: ethylene gas boiler, air supply duct, violent vibration, noise, guide plate, Karman vortex, anti-vibration plate