Configuration of the lobed nozzle in an ejector mixer for extreme mixing efficiency
Configuration of the lobed nozzle in an ejector mixer for extreme mixing efficiency
复制标题
喷射式混合器中的波瓣喷嘴配置可实现极高的混合效率
DOI：
10.1016/j.ijheatmasstransfer.2021.122102
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发表时间：
2021-10-23
影响因子：
5.2
通讯作者：
Wang, You-yuan
中科院分区：
文献类型：
--
作者：
Sheng, Zhi-qiang;Zhang, Lan;Wang, You-yuan
对一种钉状峰剑状深谷的交替波瓣喷管（NSALN-1）进行了改进，以通过增强核心区的混合来达到最终的混合效率。主要的改造包括延长剑形深谷，在剑形深谷之间增加一个中心塞，以及将剑形深谷连接起来，形成拱形深谷。对NSALN-1及其改型的射流掺混进行了数值模拟，并对改型的掺混效率进行了研究。研究发现，每种改型都能提高热混合效率，但也会降低总压恢复系数。特别是，添加适当尺寸的中心塞可以将热混合效率提高到极值，而总压恢复系数的降低保持在可接受的范围内。热混合效率在1.5 d时可达0.98，在2.0 d时可超过0.99。此外，纵向涡流的形状和位置决定了冷流通过纵向涡流被输送以与热流混合的路径的长度。因此，调节每个区域中的混合以实现平衡的混合速度有助于实现圆形凸角喷嘴的最终混合效率。(c)2021爱思唯尔有限公司版权所有。
An alternating-lobe nozzle with nail-like crests and sword deep valleys (NSALN-1) was modified to achieve the ultimate mixing efficiency by enhancing the mixing in the core region. The main modifications included extending the sword deep valleys, adding a central plug between the sword deep valleys, and connecting the sword deep valleys to form arched deep valleys. The jet mixing of NSALN-1 and its modified configurations was numerically simulated, and the efficiency of the modifications was investigated. It was found that each modification can improve the thermal mixing efficiency, but also reduce the total pressure recovery coefficient. In particular, adding a central plug of an appropriate size can increase the thermal mixing efficiency to an extreme value while the reduction in the total pressure recovery coefficient remained within an acceptable range. The thermal mixing efficiency can reach 0.98 at 1.5 d and exceed 0.99 at 2.0 d . Furthermore, the shape and position of the longitudinal vortex determine the length of the path by which the cold stream is transported to mix with the hot stream by the longitudinal vortex. Regulating the mixing in each region to achieve balanced mixing speeds is thus helpful to achieve the ultimate mixing efficiency of the circularly lobe nozzle. (c) 2021 Elsevier Ltd. All rights reserved.