基于数值仿真的 MED-TVC 喷射泵 参数优化与性能研究

蒸汽喷射泵是低温多效蒸馏海水淡化系统(MED-TVC)的关键部件.为了提升其运行效率,对蒸汽喷射泵进行了结构优化与性能分析.在喷射泵优化过程中,使用计算流体力学(CFD)工具研究了混合室直径对于引射比的影响,得到了喷射器引射比与混合室直径以及临界背压之间的拟合二次函数关系式.研究结果表明,混合室直径的增大会使引射比上升,临界背压下降.在一次流压力与二次流压力分别固定为600和15 kPa时,通过将混合室直径从15.8增大至20.35 mm,其引射比可从0.485提升至0.746,性能提升可达53.8％,造水比可以从7.425提升到8.73,提升百分比约为17.58％.优化后的蒸汽喷射泵结构可有效提升海水淡化系统的日产水量,提高系统运行效率,降低能耗.

Parameter optimization and performance analysis of the ejector used in MED-TVC system based on numerical simulation

The steam ejector is a key component of the low-temperature multi-effect distilled seawater desalination system (MED-TVC). To improve the efficiency of the system, the steam ejector has been optimized and analyzed for its structure. The influence of mixing chamber diameter on ejector ratio is studied using the computational fluid dynamics model (CFD) technology during the process of the ejector structure optimization, and the quadratic function relation between the mixing chamber diameter, the entrainment ratio, and the critical back pressure are obtained. The results show that the increase of mixing chamber diameter will lead to the increase of entrainment ratio and the decrease of critical back pressure. When the primary flow pressure and the secondary flow pressure are fixed at 600 and 15 kPa, respectively, by increasing the diameter of the mixing chamber from 15. 8 to 20. 35 mm, the ejection ratio can be increased from 0. 485 to about 0. 746, and the performance can be increased by 53. 8%. The water production ratio can be increased from 7. 425 to 8. 73, and the percentage increase is about 17. 58%. The optimized steam ejector structure can effectively increase the daily water output of the seawater desalination system, improve system operation efficiency, and reduce energy consumption.