Articles of The Transactions of KSRC

Selecting an optimal layout for a gas ejector to ensure constant outlet flow rate

Full text article ( in russian)

Year	2017
Issue	380
Volume	2
Pages	101-110
Caption	Selecting an optimal layout for a gas ejector to ensure constant outlet flow rate
Authors	Ponomarev N.N.
Keywords	ejector, diffusor, gas turbine engines
Summary	Object and purpose of research.The object of this study is a gas ejector consisting of the nozzle, the mixing chamber, the diffuser, and the duct supplying the air to the combustion chamber where the constant reduced speed is maintained. The purpose of this study is to select an optimal design for the ejector, so as to ensure the highest air entrainment ratio and not to over-complicate the whole system. Subject matter and methodsThis study applies the analytical method based on continuity equations and preservation of energy and momentum. Main results.The optimal inlet wall tilt of the diffuser was found to be 60°. To improve the efficiency of the isobaric ejector, a conical nozzle was installed behind it, with the throat size sufficient to start the ejector with serial feed of flows. Maximum air entrainment ratios for all the types of ejectors with serial feed of flows at the startup are practically equal. Conclusion.The easiest design option ensuring a high air entrainment ratio is a single-stage ejector with a supersonic diffuser of fixed geometry, selected so as to ensure serial feed of the active and the passive flow at the startup. Application of the supersonic nozzle in this ejector, instead of the sonic one, will increase the air entrainment ratio by ~10%. The analysis described in this paper allows selection of the optimal ejector for air supply to the combustion chamber of the rig.
Rubrics	Ship powering and electric systems