Influence of water spray parameters on aerodynamic characteristics and temperature drop characteristics of exhaust passage in steam turbine

Abstract

The exhaust passage of steam turbine needs water spray to reduce the temperature of exhaust steam under windage condition. To explore the influence of water spray parameters on the aerodynamic characteristics and temperature drop characteristics of exhaust passage, the relationship between the flow field characteristics and the spray parameters is investigated by regression orthogonal test. The results show that the influence of spray parameters on the total-temperature drop coefficient (CTt) and the static pressure recovery coefficient (Cpt) of exhaust passage is nonlinear. The main influencing parameters on the total-temperature drop coefficient are the droplet diameter and the water mass flow rate, the main influencing parameter on the static pressure recovery coefficient is the water mass flow rate. The influence of each spray parameter on the flow field characteristics is independent. The optimal water spray scheme can be obtained by the regression equation to improve the aerodynamic characteristics of exhaust passage. When the weight coefficient of flow field characteristics ε is 0.3, the total-temperature drop coefficient and the static pressure recovery coefficient of optimal scheme are 20.9% and 26.5%, respectively. The average total-temperature drop is 77.4K.When the weight coefficient of flow field characteristics ε is 0.5, the total-temperature drop coefficient and the static pressure recovery coefficient of optimal scheme are 19.9% and 31.6%, respectively. The average total-temperature drop is 74.1K. Therefore, the aerodynamic characteristics of exhaust passage and the exhaust temperature can be controlled in a reasonable range.