基于有机朗肯循环系统的多管式相变蓄热器的设计

Design of Multi-Tube Phase Change Heat Accumulators Based on Organic Rankine Cycle Systems

为保证有机朗肯循环系统的稳定供电,对有机朗肯循环系统设计相变蓄热器,采用数值模拟的方法,选择外径dout,外径与内径的比值dout/din,管距与内径的比值d/din作为相变蓄热器的结构参数,研究不同的结构参数对相变蓄热器性能的影响。结果表明:随蓄热器外径与内径比值的增大,蓄热速率在不断减小,又因为重力作用产生的浮升力引起自然对流,在液相率达到0.95以后蓄热速率随比值增大而减小,外径与内径比值为10时完全融化所需的总蓄热时间最短;随着蓄热器管距与内径比值的减少,蓄热效果也越来越好,但当比值减小到一定范围后,其蓄热速率增大的有效性会随着比值的减小逐渐降低,模拟得出管距与内径比值为2时总融化时间最短;随着外径的增大,相变蓄热器的蓄热速率及蓄热时间都有所增加,外径dout每增大0.2 m,蓄热时间增加36.5%。

In order to ensure the stable power supply of the organic Rankine cycle system, a phase change accumulator was designed for the organic Rankine cycle system, and numerical simulation was used to select the outer diameter dout, the ratio of outer diameter to inner diameter dout/din, and the ratio of tube distance to inner diameter d/din as the structural parameters of the phase change accumulator, and to study the influence of different structural parameters on the performance of the phase change accumulator. The results show that: With the increase of the ratio of the outer diameter to the inner diameter of the regenerator, the heat storage rate decreases continuously. Due to the natural convection caused by the buoyancy force generated by gravity, the heat storage rate decreases with the increase of the ratio after the liquid phase ratio reaches 0.95. When the ratio of the outer diameter to the inner diameter is 10, the total heat storage time required for complete melting is the shortest;as the ratio of the distance between the tube and the inner diameter of the accumulator decreases, the heat storage effect is also getting better, but when as the ratio decreases to a certain range, the effectiveness of the heat storage rate decreases as the ratio decreases, and the simulation shows that the total melting time is shortest for a ratio of 2;as the outer diameter increases, the heat storage rate and time of the phase change accumulator increases, and the heat storage time increases by 36.5% for each 0.2 m increase in outer diameter dout.