The surface roughness effect on the performance of supersonic ejectors / Brezgin D. V.,Aronson K. E.,Mazzelli F.,Milazzo A. // THERMOPHYSICS AND AEROMECHANICS. - 2017. - V. 24, l. 4. - P. 553-561.

ISSN/EISSN:

0869-8643 / 1531-8699

Type:

Article

Abstract:

The paper presents the numerical simulation results of the surface roughness influence on gas-dynamic processes inside flow parts of a supersonic ejector. These simulations are performed using two commercial CFD solvers (Star- CCM+ and Fluent). The results are compared to each other and verified by a full-scale experiment in terms of global flow parameters (the entrainment ratio: the ratio between secondary to primary mass flow rate - ER hereafter) and local flow parameters distribution (the static pressure distribution along the mixing chamber and diffuser walls). A detailed comparative study of the employed methods and approaches in both CFD packages is carried out in order to estimate the roughness effect on the logarithmic law velocity distribution inside the boundary layer. Influence of the surface roughness is compared with the influence of the backpressure (static pressure at the ejector outlet). It has been found out that increasing either the ejector backpressure or the surface roughness height, the shock position displaces upstream. Moreover, the numerical simulation results of an ejector with rough walls in the both CFD solvers are well quantitatively agreed with each other in terms of the mean ER and well qualitatively agree in terms of the local flow parameters distribution. It is found out that in the case of exceeding the ``critical roughness height{''} for the given boundary conditions and ejector's geometry, the ejector switches to the ``off-design{''} mode and its performance decreases considerably.

Author keywords:

supersonic ejector; entrainment ratio; CFD; wall log-law; sand-grain roughness R245FA

DOI:

10.1134/S0869864317040060

Web of Science ID:

ISI:000412462300006

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JUL
Publisher	MAIK NAUKA/INTERPERIODICA/SPRINGER
Address	233 SPRING ST, NEW YORK, NY 10013-1578 USA
Language	English
EISSN	1531-8699
Keywords-Plus	R245FA
Research-Areas	Thermodynamics; Mechanics
Web-of-Science-Categories	Thermodynamics; Mechanics
Author-Email	k.e.aronson@urfu.ru
Number-of-Cited-References	17
Usage-Count-Last-180-days	2
Usage-Count-Since-2013	2
Journal-ISO	Thermophys. Aeromechanics
Doc-Delivery-Number	FJ1GN