Investigation on the Effects of Flow Rate and Temperature of Cooling System on SCO2 Axial Turbine
The cooling system was designed in a supercritical carbon dioxide axial turbine to control the operating temperature of the dry gas seal below 200℃for safe operation,that the turbine dry gas seal,rotor and casing were cooled by the low temperature SCO2 extracted from the pipe downstream the compressor.A coupled computational model was established for the cooling system of a low-power SCO2 axial turbine,including the cooling fluid domain,mainstream fluid domain,and solid domain.The influence of different dry gas seal cooling flow rates and temperatures on cooling effectiveness and turbine efficiency were compared and analyzed.Based on this,coupled temperature field and pressure field calculations were carried out to evaluate the strength of entire turbine.The results showed that the external low-temperature SCO2 can effectively cools the entire rotor system.As the cooling flow rate increases,turbine efficiency and rotor system temperature decrease gradually.The smaller cooling flow rate leads to the greater efficiency and temperature variations caused by the same change in cooling flow rate.As the cooling gas temperature increases,the turbine efficiency remains relatively stable,while the rotor system temperature linearly increases.When the cooling gas temperature is 120℃and the flow rate is 0.04kg/s,the turbine rotor system can meet the requirements,the working temperature of the dry gas seal is 194℃.The strength evaluation results indicated that the maximum equivalent stress of turbine was 536MPa,located at the root of the turbine blade.The stress in each component was below the material's yield strength,with a minimum safety margin of 1.57,satisfying the long-term safe.
SCO2Axial TurbineCoolingSystemHeat Transfer CharacteristicsTemperature Distribution
万方数据
维普
