并联螺旋管通道流动不稳定性现象研究

Background]: Helical tube once-through steam generator is widely utilized in the design of advanced small reactors, forced circulation boiler and quench boiler. Flow instability is a critical thermal-hydraulic issue, but lack of comprehensive research on this phenomenon in parallel helical tubes. [Purpose]: This study conducted experiments on a helical tubes thermal-hydraulic apparatus. [Methods]: The effects of thermal parameter were investigated at the range of 7-13MPa, mass flow rate from 100-550kg/m2s and helical coil diameter from 370-800mm. [Results]: It was found that high system pressure and high inlet flow rate contribute significantly to more stable system. Inlet subcooling has a minimal impact on the critical load at conditions with low pressure, low flow rate and low inlet subcooling. The system stability boundary exhibits an "S" shape under high system pressure but transitions to an "L" shape under low system pressure, which is associated with the multivalued influence of inlet subcooling on system stability. [Conclusion]: This work fills the gap in experimental data on flow instability in parallel helical tubes, providing a solid data foundation for in-depth analysis of flow instability phenomena.