Han Yu, Wang Xiaodong, Li Ao, A Elbarghthi Anas F, Wen Chuang
School of Mechanical and Electrical Engineering, Suqian University, Suqian 223800, China.
School of Mechanical Engineering & Automation, Northeastern University, Shenyang 110819, China.
Entropy (Basel). 2022 Nov 9;24(11):1625. doi: 10.3390/e24111625.
The steam ejector is valuable and efficient in the fire suppression field due to its strong fluid-carrying capacity and mixing ability. It utilizes pressurized steam droplets generated at the exit to extinguish the fire quickly and the steam droplet strategy allows for an expressive decrease in water consumption. In this regard, the fire suppression process is influenced by the steam ejector efficiency, the performance of the pressurized steam, and the ejector core geometry, which controls the quality of the extinguishing mechanisms. This study investigated the impact of different mixing section diameters on the pumping performance of the ejector. The results showed that change in the diffuser throat diameter was susceptible to the entrainment ratio, which significantly increased, by 4 mm, by increasing the throat diameter of the diffuser and improved the pumping efficiency. Still, the critical back pressure of the ejector reduced. In addition, the diameter effect was studied and analyzed to evaluate the ejector performance under different operating parameters. The results revealed a rise in the entrainment ratio, then it diminished with increasing primary fluid pressure. The highest entrainment ratio recorded was 0.5 when the pressure reached 0.36 MPa at the critical range of back pressure, where the entrainment ratio remained constant until a certain back pressure value. Exceeding the critical pressure by increasing the back pressure to 7000 Pa permitted the entrainment ratio to reduce to zero. An optimum constant diameter maximized the ejector pumping efficiency under certain operating parameters. In actual design and production, it is necessary to consider both the exhaust efficiency and the ultimate exhaust capacity of the ejector.
蒸汽喷射器因其强大的流体输送能力和混合能力，在灭火领域具有重要价值且效率颇高。它利用出口处产生的加压蒸汽滴快速灭火，蒸汽滴策略能显著减少用水量。在这方面，灭火过程受蒸汽喷射器效率、加压蒸汽性能以及控制灭火机制质量的喷射器核心几何形状影响。本研究调查了不同混合段直径对喷射器泵送性能的影响。结果表明，扩压器喉部直径的变化易影响引射比，通过增大扩压器喉部直径4毫米，引射比显著增加，并提高了泵送效率。不过，喷射器的临界背压降低了。此外，还研究分析了直径效应，以评估不同运行参数下喷射器的性能。结果显示，引射比先上升，然后随着一次流体压力的增加而减小。在背压的临界范围内，当压力达到0.36兆帕时，记录到的最高引射比为0.5，在该范围内引射比保持恒定，直到达到某个背压值。通过将背压增加到7000帕超过临界压力，会使引射比降至零。在某些运行参数下，一个最佳恒定直径可使喷射器的泵送效率最大化。在实际设计和生产中，有必要同时考虑喷射器的排气效率和最终排气能力。
