Analysis on high temperature strength and sealing behavior of U-type seal in steam turbine valves

作者：Mao, Jianfeng; Zhang, Junhui; Wang, Weizhe; Chen, Hanping

来源：Proceedings of the CSEE, 2013, 33(20): 104-110.

• Creep deformations
• High temperature creep
• High temperature strength
• Inlet valve
• Multi-axial state of stress
• Operational parameters
• Sealing performance
• Supercritical steam turbines

U-type seal has been widely used in the inlet valves of ultra-supercritical steam turbines due to its superior sealing performance. However, the U-type seal bears greater creep deformation with the increase of the operational parameters (T, P). In order to investigate the creep strength and sealing performance of the U-type seal, the modified time-hardening Norton-Bailay constitutive equation and multiaxial cavity growth model were employed in the calculation. Furthermore, the variation of contact position, contact stress and multiaxial factor of U-type seal of steam turbine valve were analyzed under 0.2 million creep hours. The results illustrate that the contact stress of U-type seal significantly reduces with the creep hours increases. Some key areas of U-type seal suffer great multi-axial state of stress, and then huge Cock-Ashby equivalent strain is produced. The experimental result is consistent with predicted result.

• 出版日期2013
• 单位上海交通大学