带有前置泵的有机朗肯循环实验

Experiment on Organic Rankine Cycle Performance with Booster Pump

针对基本有机朗肯循环(B-ORC)在运行时工质泵易发生气蚀,提出了带有前置泵的有机朗肯循环(BPORC),并建立了实验装置。采用不锈钢磁力泵作为前置泵,安装于工质泵与储液罐之间,用于提升工质泵入口压力,从而确保工质泵入口有足够的气蚀余量。采用三氟二氯乙烷(R123)作为循环工质,在140℃热源条件下进行实验,对比了B-ORC和BP-ORC系统运行的稳定性和高效性。实验结果表明,前置泵可有效解决工质泵气蚀问题,使得有机工质流量不发生显著偏离和剧烈波动,工质流量波动幅值从±22 kg/h下降至±2.1 kg/h。相同条件下BP-ORC膨胀机输出轴功增大,当工质泵频率f为7 Hz时,膨胀机最大轴功从2.11 k W提升至2.35 k W,增幅为11.4%。本实验中前置泵功耗为0.3 k W,当不考虑前置泵自身功耗时,系统输出净功和热效率都明显提升,最大热效率从5.78%升至6.16%;计入前置泵功耗时,系统最大热效率则降至5.27%。

Organic Rankine cycle（ ORC） is a promising approach to utilize the low grade heat sources.For basic organic Rankine cycle（ B-ORC）, working fluid circulating pump is one of the main components with low efficiency and suffering cavitation problem. To improve the situation,organic Rankine cycle with booster pump（ BP-ORC） was proposed,and an experimental setup was constructed.A stainless steel magnetic drive pump was used as booster pump which was installed between circulating pump and reservoir. Dichlorotrifluoroethane（ R123） was selected as working fluid,and a scroll expander was used to produce shaft work. At the heat source temperature of 140℃,comparative experiment was organized to compare the stabilization and effectiveness between B-ORC and BP-ORC. The results showed that booster pump can overcome the cavitation of circulating pump effectively,resolve the deviation of working fluid mass flow rate obviously,and reduce the scale of oscillation of mass flow rate at the same time. The intension of oscillation was reduced from ± 22 kg / h to ± 2. 1 kg / h. The maximum shaft power of expander was raised from 2. 11 k W to 2. 35 k W when the frequency of circulating pump was 7 Hz. The power consumption of booster pump was about 0. 3 k W. Net thermal efficiency was raised from 5. 78% to6. 16% when the booster pump consuming power was ignored,while it was fallen to 5. 27% when the booster pump consuming power was considered. The results identified that the reasonable selection of booster pump is necessary.