关键词: 蒸汽蓄热器, 放汽管路, 热冲击特性

Abstract:

The ship discharging pipe has characteristics of short discharging period, high thermal shock energy and large fluctuation load, which directly affect safe and steady operation of a steam accumulator. In this study, typical ship steam accumulator discharging pipe is taken as the prototype. Turbulent fluctuation is analyzed by using the standard k-ε equation. The hydrodynamic characteristics for ship steam accumulator discharging pipe are calculated by CFD simulation method. Velocity, pressure, turbulence kinetic energy and wall shear distributions are obtained. Based on the prediction mechanisms of thermal shock generated by flow induced vibration, shock energy pictures closely related to flow induced vibration are revealed. The calculated results show that during mixed flow of high temperature and pressure steam, high velocity, severe turbulence fluctuation and large wall shear occur around T-junction. Based on steam thermal shock energy pictures, thermal shock energy is higher at the elbow and T-junction, while the maximum shock energy occurs at the T-junction for discharging pipe. These calculated results predict that thermal shock damage for T-junction is more serious. The actual test data for T-junction demonstrate the numerical prediction results.

Key words: steam accumulator, discharging pipe, thermal shock characteristics