Research on the Performance and Multi-Field Coupling Regulation Mechanism of the Nozzle-Adjustable Steam Ejector.
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| Title: | Research on the Performance and Multi-Field Coupling Regulation Mechanism of the Nozzle-Adjustable Steam Ejector. |
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| Authors: | Li, Yiqiao1 (AUTHOR) liyiqiao@djtu.edu.cn, Ge, Caijing1,2 (AUTHOR), Han, Yulong1 (AUTHOR), Huang, Hao1,2 (AUTHOR), Liu, Xiaodong1 (AUTHOR), Li, Hua1 (AUTHOR), Shen, Shengqiang2 (AUTHOR) zzbshen@dlut.edu.cn |
| Source: | Energies (19961073). Jul2026, Vol. 19 Issue 13, p3186. 32p. |
| Subject Terms: | *Shock waves, *Phase transitions, *Nonequilibrium thermodynamics, *Mathematical optimization, *Fluid flow |
| Abstract: | Adjustable steam ejectors exhibit significant adaptability to various operating conditions. However, the coupling regulation mechanism between ejector performance and the internal flow field remains insufficiently understood, thereby limiting further optimization. The novelty of this study lies in elucidating the ejector's performance regulation mechanism by examining the influence of spindle position on non-equilibrium condensation in wet steam. This approach clarifies the flow–thermal–phase-change coupling mechanism and interprets the resulting condensation suppression and shock wave dynamics. In this study, the effects of operating conditions and spindle position on ejector performance were quantitatively characterized. The flow-field evolution was further analyzed through key flow-field variables (pressure, Mach number, temperature, and condensate mass fraction). Moreover, the relationship between ejector performance and flow characteristics was investigated. The flow–thermal–phase-change coupling analysis reveals that the spindle effectively regulates steam ejector performance, internal thermodynamic behavior, and phase-transition processes by adjusting the equivalent throat diameter. Under a representative operating condition, compared with the baseline position (dt = 5.66 mm), moving the spindle in the positive x-axis direction (to dt = 5 mm) decreased the equivalent throat diameter and the motive-fluid mass flow rate by 11.7% and 22.6%, respectively. Consequently, the distance between adjacent shock waves gradually decreased along the flow direction (by approximately 14.1%), and the global maximum Mach number decreased sharply from 2.0 to 1.6 (a 20% reduction). The jet core was significantly shortened, while both the intensity and number of shock waves in the diffuser were reduced. Additionally, the local backflow near the wall of the mixing chamber's contraction section was suppressed, resulting in a weaker temperature rise in the backflow region. The fluid temperature approached the outlet temperature more gradually, while the average flow-field temperature increased. Meanwhile, the condensate mass fraction in the mixing chamber was significantly reduced (from 0.1 to 0), and the entrainment ratio was enhanced. This configuration is suitable for applications requiring low discharge pressure, high motive pressure, or high suction pressure. Conversely, moving the spindle in the negative x-axis direction enlarged the equivalent throat diameter, which generated higher Mach numbers and stronger shock waves. This enlarged throat configuration enhances the ejector's resistance to elevated discharge pressure and increases the critical discharge pressure, making it more suitable for high discharge pressure, low motive pressure, or low suction pressure conditions. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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