用于核电余热高效回收的梯级相变填充床储热系统优化设计

To address the challenge of waste heat management in lead-bismuth-cooled nuclear reactor Systems during accident scenarios, a waste heat management method based on packed-bed latent thermal energy storage (PLTES) is proposed. By establishing a numerical model of PLTES constrained by an outlet threshold temperature, this paper analyzes the effects of phase-change materials (PCM) mclting points and filling ratios on the thermal Performance of single-stage and cascade PLTES Systems. The rcscarch results show that in the single-stage PLTES System, rcgardlcss of the usc of high or low melting point PCM, it is difficult to fully exploit the sensible and latent heat potential of PCM, resulting in a maximum System capacity utilization rate rjma of only 74. 17%. In contrast, the research on cascade PLTES Systems indicates that by placing PCM with melting points bclow the infrarcd dctcction thrcshold tcmperature at the bottom of the System and using PCM with melting points higher than the heat release outlet threshold temperaturc at the top layer, it is possiblc to significantly increase the System's cnergy storage density while ensuring that the cmission temperaturc is close to the ambient temperature. Through precise adjustment of the melting points and filling ratios of PCM at each level, the optimized cascade PLTES System (with dimensionlcss melting points of top, middlc, and bottom laycr PCM bcing 0. 480, 0. 260, 0. 012 rcspcctively, and filling ratios of 0. 52, 0. 44, 0. 04) achieves a PCM solid-liquid phasc change participation rate of 97. 9% and rjma of 87. 22%. This research provides reference for the application of packcd bed thermal cnergy storage in the efficient recovery of waste heat in nuclcar power plants.