Numerical Investigation of the Effect of Air Leaking into the Working Fluid on the Performance of a Steam Ejector

He Li,Jiuxin Ning,Xiaodong Wang,Hailong Huang,Pengfei Zhang

doi:10.3390/app11136111

Abstract

This paper investigated the effect of air leaking into the working fluid on the performance of a steam ejector. A simulation of the mixing of air into the primary and secondary fluids was performed using CFD. The effects of air with a 0, 0.1, 0.3 and 0.5 mass fraction on the entrainment ratio and internal flow structure of the steam ejector were studied, and the coefficient distortion rates for the entrainment ratios under these air mass fractions were calculated. The results demonstrated that the air modified the physical parameters of the working fluid, which is the main reason for changes in the entrainment ratio and internal flow structure. The calculation of the coefficient distortion rate of the entrainment ratio illustrated that the air in the primary fluid has a more significant impact on the change in the entrainment ratio than that in the secondary fluid under the same air mass fraction. Therefore, the air mass fraction in the working fluid must be minimized to acquire a precise entrainment ratio. Furthermore, this paper provided a method of inspecting air leakage in the experimental steam ejector refrigeration system.

Highlights

This paper investigated the effect of air leaking into the working fluid on the performance of a steam ejector
To investigate the effect of air on the ejector performance, we used four air mass fractions (0, 0.1, 0.3, and 0.5), and marked Y1 as the air mass fraction leaking into the primary fluid and Y2 as that leaking into the secondary fluid
We set the primary fluid, secondary fluid, and back pressures as 270, 1.2, and 3 kPa, respectively. It was impossible for air with mass fractions of 0.3 and 0.5 to leak into the steam ejector refrigeration systems (RES), but these mass fractions were more suitable for obtaining results with a pronounced trend

Summary

Introduction

This paper investigated the effect of air leaking into the working fluid on the performance of a steam ejector. The effects of air with a 0, 0.1, 0.3 and 0.5 mass fraction on the entrainment ratio and internal flow structure of the steam ejector were studied, and the coefficient distortion rates for the entrainment ratios under these air mass fractions were calculated. The steam ejector can, use industrial waste heat generated by heating and power plants, and has the advantages of a simple structure, convenient operation, easy maintenance, and environmental friendliness. It is widely used in vacuuming, refrigeration, heat recovery, and desalination of seawater and has received considerable research attention. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

Results

Discussion

Conclusion