相变材料对非能动系统换热管性能影响研究

The equal height difference passive containment cooling system (PCCS) of marine nuclear platforms is prone to insufficient heat transfer and flow instability during the initial phase of accidents. To improve the passive system performance, phase change materials (PCMs) with high latent heat and isothermal heat absorption characteristics have been employed for the cooling system. An Apros simulation model for the PCCS integrated with PCMs was established, and the influence law of the PCM coupling on the operational characteristics and heat transfer performance of natural circulation heat exchange tubes was comparatively analyzed through calculation. Results demonstrate that after PCM coupling, the natural circulation resistance can be reduced effectively, with the peak resistance at the top of heat exchange tubes decreasing from 1 510 Pa to 1 310 Pa, representing a reduction exceeding 13% . The transition moment from gaseous phase to gas-liquid two-phase state of cooling water at the outlet of natural circulation heat exchange tube is advanced from 80 s to approximately 60 s. The PCM enables faster attainment of peak convective heat transfer coefficients in the tubes, accelerates the establishment and stabilization of natural circulation, and effectively mitigates the insufficient heat transfer issue of natural circulation during the initial accident phase.