Scholarlink

<p>During the reconstruction of the steam turbine condenser (STC), a steam bypass system (SBS) was installed to route steam directly from the heat recovery steam generator (HRSG) to the condenser during turbine trips and boiler start-ups. The integration of the SBS introduced additional thermal and mechanical loads on the STC cooling tubes, potentially affecting condenser reliability and performance. Following the reconstruction, a comprehensive analysis of the condenser cooling tubes was conducted to identify potential failure mechanisms. The investigation included visual inspection, metallographic examination, mechanical testing, scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS), fracture surface analysis of the inner and outer tube surfaces, surface hardness measurements, tensile testing, and measurements of the quality and mass flow rate of the inlet steam under real operating conditions. The material analyses showed no evidence of corrosion caused by sulphates or ammonia. Cracks were found to originate from the inner tube surface and were consistently located approximately 40&#xa0;mm from the tube end near the condenser wall. Mechanical tests confirmed that the tube material exhibits high ductility and can withstand significant plastic deformation without cracking. Numerical and modal analyses indicated that vibration-induced bending stresses, combined with thermal stresses caused by temperature differences between the cooling water and steam, create critical tensile stresses on the inner tube wall. CFD simulations further showed that steam velocities in certain areas of the condenser exceed the critical threshold for tube vibration. The results indicate that the observed cracking is primarily associated with vibration-induced fatigue combined with thermal loading at the water inlet region, highlighting the need for improved operational control and monitoring to ensure reliable long-term operation.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Steam turbine condenser cooling tubes analysis after HP and IP steam bypass modification

  • 期刊论文

  • 发表日期：

    2026年4月14日

查看全文
  • Dušan Strušnik,
  • Jurij Avsec

摘要

During the reconstruction of the steam turbine condenser (STC), a steam bypass system (SBS) was installed to route steam directly from the heat recovery steam generator (HRSG) to the condenser during turbine trips and boiler start-ups. The integration of the SBS introduced additional thermal and mechanical loads on the STC cooling tubes, potentially affecting condenser reliability and performance. Following the reconstruction, a comprehensive analysis of the condenser cooling tubes was conducted to identify potential failure mechanisms. The investigation included visual inspection, metallographic examination, mechanical testing, scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS), fracture surface analysis of the inner and outer tube surfaces, surface hardness measurements, tensile testing, and measurements of the quality and mass flow rate of the inlet steam under real operating conditions. The material analyses showed no evidence of corrosion caused by sulphates or ammonia. Cracks were found to originate from the inner tube surface and were consistently located approximately 40 mm from the tube end near the condenser wall. Mechanical tests confirmed that the tube material exhibits high ductility and can withstand significant plastic deformation without cracking. Numerical and modal analyses indicated that vibration-induced bending stresses, combined with thermal stresses caused by temperature differences between the cooling water and steam, create critical tensile stresses on the inner tube wall. CFD simulations further showed that steam velocities in certain areas of the condenser exceed the critical threshold for tube vibration. The results indicate that the observed cracking is primarily associated with vibration-induced fatigue combined with thermal loading at the water inlet region, highlighting the need for improved operational control and monitoring to ensure reliable long-term operation.