DEC advanced seal (DAS) is a key component to suppress fluid leakage in turbomachinery.Taking a certain unit diaphragm seal as object,computational fluid dynamics (CFD) model of DAS is established to study the influence of different operating conditions of pressure ratios and rotational speeds and structural parameters such as DAS tooth thickness,DAS tooth numbers and installation position on the seal leakage.Results show that the DAS leakage flowrate increases with the increase of pressure ratio,showing better linear correlation; the DAS leakage flowrate decreases with the increase of rotational speed,and increases first and then decreases with the increase of DAS tooth thickness.When the DAS tooth thickness of 1.17 mm is 9 times of the lowspeed tooth thickness of 0.13 mm,the leakage reaches the maximum.With the increase of the number of DAS teeth,the influence of DAS teeth on leakage in different installation positions gradually decreases.The best installation position of 1 DAS tooth is close to the inlet section,which reduces the leakage by 4.65% compared with the original model;the best installation positions of the 2 DAS teeth are respectively installed near the inlet and outlet sections,reducing the leakage by 7.81% compared with the original model;the leakage of the three DAS teeth is reduced by up to 1101% compared to the original model.

TK263.6

国家自然科学基金(51875361)；上海市自然科学基金(20ZR1439200)