Numerical simulation on exhaust hood model with different inner guide ring angles and widths at outlet of the diffuser was performed

by using the Fluent software.The results show that:the optimal inner guide ring angleβwas 75°

with which the pressure loss of the exhaust hood reduced by 41.2Pa

compared with theβ=0°condition;the optimal outlet width d was 1 250 mm

with which the pressure loss dropped by 16.8Pa

compared with the d=1 100 mm condition;adding a series of baffles at the exhaust hood downstream can divide the vortex with heavier intensity into multiple weaker vortexes

thus to control the strength and range of the vortexes.After the dampers were installed

the pressure loss decreased by27.8Pa.Application of the retrofitted exhaust hood on a 600 MW unit indicated that

the pressure loss of the exhaust hood dropped by 69 Pa

and the effective specific enthalpy drop increased by 0.08%.