Suppression of Rotating Stall in Vaneless Diffuser by Wall Roughness Control

Autor:	Masahiro Ishida, Hironobu Ueki, Daisaku Sakaguchi, Zixiang Sun
Rok vydání:	2000
Předmět:	Pressure drop Boundary layer Impeller Materials science Turbulence Mechanical Engineering Drop (liquid) Stall (fluid mechanics) Mechanics Condensed Matter Physics Tangential and normal components Volumetric flow rate
Zdroj:	TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B. 66:2101-2108
ISSN:	1884-8346 0387-5016
DOI:	10.1299/kikaib.66.648_2101
Popis:	The authors have proposed a new technique to suppress successfully the rotating stall in the vaneless diffuser. By positioning the completely rough wall between R=1.2 and 1.6 on the hub side diffuser wall alone, the flow rate of rotating stall inception was decreased by 42% at a small pressure drop less than 1% of the blower pressure rise. This is based on that the local reverse flow occurs firstly at the hub side in most centrifugal blowers with backswept blade impeller mainly depending on the distortion of tangential component of inlet main-flow velocity. The 3-D boundary layer calculation shows that the local reverse flow is decreased remarkably by an increase in wall friction, and it disappears if the friction coefficient is 0.01 about twice of the smooth wall. By analyzing the effect of wall friction and turbulence induced by the rough wall, it is clearly shown that the rough wall positioned in the limited region, where the wall-limiting streamline flow angle shows the negative maximum, is quite effective to suppress the rotating stall at a small drop of the diffuser pressure recovery.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::54900c87733abbb9f8ba4f31395f0fad https://doi.org/10.1299/kikaib.66.648_2101 Zobrazit plný text záznamu