多孔介质中熔融盐流体高温斜温层蓄热的热特性

Thermal Analysis on the Single-Phase Flow through Porous Media in the High-Temperature Molten Salt Thermocline Thermal Energy Storage System

对熔融盐高温斜温层蓄热过程进行了较深入的理论与实验研究.基于多孔介质局部热平衡理论,建立了多孔介质中熔融盐流体斜温层蓄热的局部热平衡数值模型,研究了熔融盐、多孔介质孔隙结构参数对多孔介质中熔融盐流体传热与流动的影响规律,并在熔融盐传热-蓄热实验平台上进行了试验研究.结果表明:与熔融盐单相流体斜温层(无填充多孔介质)蓄热系统相比,多孔介质填料能够减少斜温层的厚度和改善其形状,采用单位体积热容量(pc)s大于(pc)f,孔隙率(?)小于0.4有利于降低斜温层厚度及其移动速度.揭示了多孔介质中熔融盐流体斜温层蓄热系统的蓄热特性,为熔融盐高温斜温层蓄热的设计和运行控制提供依据.

The theoretical analysis, numerical simulation and experimental investigation on the heat storage and heat transfer characteristics of the high-temperature molten salt thermocline thermal energy storage （TES） system have been presented in this paper. First, based on the local thermal equilibrium （LTE） assumption, the heat transfer and heat storage simulation model of the single-phase flow through porous media in the molten salt thermocline system is provided, and the influences of the thermal-physical parameters of the molten salt and porous media, the pore structure of the porous media on the thermal energy storage performance are analyzed. Then, the related experimental investigations are carried out on the molten salt heat transfer testing platform. Comparing with the single-phase flow molten salt thermocline system （with non-filled porous media）, to fill appropriate porous media will decrease the thickness of thermocline layer and improve its shape. It is more appropriate to control the （pC）s to be larger than the （pC）f and the porosity value to be under 0.4. The heat storage and heat transfer characteristics of the single-phase flow through porous media in the molten salt thermocline TES system are revealed, which will provide an important basis for the design and operation control of the molten salt high temperature thermocline system.