Numerical Analysis of the Effect of Water to Steam Ratio on Temperature Drop of a Turbine Pre-swirl Air Supply System
To reveal the influence of the wet air conditions caused by water injection pre-cooling on the temperature of the turbine air supply system,this paper focused on the influence evaluation of wet air on the temperature drop of pre-swirl air supply system under the conditions of total pressure of 150 kPa and total temperature of 450 K at the inlet of the pre-swirl air supply system based on Euler-Lagrangian multi-phase flow particle tracking method.The variation laws of both swirl ratio of the system and flow coeffi-cient of pre-swirl nozzle were analyzed in detail.The influence law of temperature drop of the pre-swirl air supply system was revealed.Results show that the water to steam ratio has a significant effect on the flow and temperature in pre-swirl nozzle as the water to steam ratio increases from 0 to 0.3.The airflow swirl ratio of pre-swirl nozzle increases from 1.36 to 1.43,while its pressure ratio decreases from 1.523 to 1.482,and its flow coefficient drops from 0.97 to 0.90,thus reducing the temperature drop of pre-swirl nozzle form 25.79 K to 22.28 K;in particular,the temperature drop of pre-swirl air supply system is re-duced from 12.07 K to 11.03 K.It can be concluded that the flow resistance in the system will increase under the system inlet conditions with humidity so as to limit the cooling ability of the pre-swirl air supply system.Therefore,the air supply pressure of the system will be required higher at the humidity conditions when the air supply temperature of the turbine blade is constant.
gas turbine enginepre-swirl air supply systemwater to steam ratioswirl ratiotemperature drop
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