Study on the Thermal Characteristics of a Two-Phase Single-Screw Expander for Total-Flow Geothermal Power Generation

被引：0
|
作者：
Nie T. [1 ]
Zhou H. [1 ]
Shao H. [1 ]
Wang Z. [1 ]
机构：
[1] College of New Energy, China University of Petroleum (East China), Shandong, Qingdao
来源：
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | 2024年 / 58卷 / 05期
关键词：
geothermal energy; single-screw expander; thermal characteristics; two-phase wet steam;
D O I：
10.7652/xjtuxb202405018
中图分类号：
学科分类号：
摘要：
In response to the low system efficiency and heat source utilization in geothermal power generation technology, the thermal characteristics of a single-screw expander used in a total-flow cycle power generation system as an alternative to the traditional steam turbine arc analyzed. Based on the mass and energy conservation equations and wet-steam virial equation of state, a thermodynamic model is formulated for the total-flow expansion involving liquid flash and vapor-liquid equilibrium. The influence of inlet temperature and dryness on the state of vapor-liquid two-phase working medium and the thermal characteristics of the expander is examined. The results show that elevating the inlet temperature from 140 °C to 170 °C enhances the mass, pressure, and temperature of the wet steam working medium, and the output power of the single-screw expander rises from 210 kW to about 260 kW, with the isentropic efficiency becoming optimal at 77% at the inlet temperature of 160 °C. Improving the inlet steam dryness diminishes the quality of the working medium of the wet steam entering the working chamber, causing a subsequent reduction in medium pressure and temperature after the expansion. However, this significantly boosts expander performance parameters, including output power and isentropic efficiency. With an inlet steam dryness of 0. 3, the output power of the single screw expander exceeds 500 kW, and the isentropic efficiency reaches 76. 5%. The study outcomes provide reference for the analysis and improvement of thermal characteristics of a two-phase single-screw expander used for geothermal energy total-flow power generation, as well as the optimization of total-flow power generation technology. © 2024 Xi'an Jiaotong University. All rights reserved.
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页码：190 / 199
页数：9
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