Characteristics of static pre-cyclonic steam ejector

Abstract

The thermal vapor recompression (TVR) technology can partially recover condensation latent heat of the secondary steam in the multi-effect evaporation (MEE) process. And the two-dimension of x and r momentum exchange in the key device-steam ejector, makes induction efficiency relatively low and mixing length long. In this article, a novel three-dimensional momentum exchanging ejector called static pre-cyclonic steam ejector (SCSE) is first proposed. Its performances are mainly evaluated by means of computational fluid dynamics(CFD) at different dynamic pressure ratios (DPRs) and preliminarily validated by experiments. The SCSE can not only reduce the axial dimension of conventional ejector, but also show excellent performance at a low boosted pressure occasions. The SCSE with DPR = 4/1 improves the entrainment ratio(ER) by 10.8% compared to traditional ejector. For cases with secondary flow pressure disturbances, the application of the SCSE is limited because of an adverse impact on the operation stability. For cases with outlet flow fluctuates, the SCSE with larger DPR has higher peak ER and narrower choked-band-width at respective break-down supercharging ratios (BSRs), and there are no obvious influences on the operation stability for SCSE.