NUMERICAL CALCULATION ON HEAT EXCHANGER TUBE THERMAL FATIGUE LIFE IN COLD ENVIRONMENTS

摘要

A series of numerical analyses are conducted with the assistance of coupled computational fluid dynamics (CFD) and structural analysis to estimate the air-cooled steam condensing heat exchanger tube life expectancy in extremely cold ambient conditions. The temperature profile of a heat exchanger tube from CFD is used as boundary conditions for stress-strain analysis. The effect of ambient air temperature, air velocity, steam pressure, steam velocity, tube material, tube wall thickness, non-condensable stagnation zone length, and tube ends supporting configuration are considered. The fatigue life expectancy of the tube is calculated using the Goodman fatigue equation. It is found that minimizing the temperature difference between the tube internal and external temperatures is key to heat exchanger tube protection in cold environments.