Effects of Impeller Squealer Tip on Centrifugal Compressor Performance

Abstract

This paper summarizes the main results sorted out from a design of experiment (DoE) based on a validated computational fluid dynamics (CFD). Several tip recessed geometries applied to an unshrouded impeller were considered in conjunction with two tip clearance levels. The computations show that recessed tip geometries have positive effects when considering high-flow coefficient values, while in part-load conditions the gain is reduced. Starting from the results obtained when studying tip cavities, a single rim tip squealer geometry was then analyzed: the proposed geometry leads to performance improvements for all the tested conditions considered in this work.

Flow Control Methods and Their Applicability in Low-Reynolds-Number Centrifugal Compressors—A Review

“…Increase in squealer cavity depth reduces performance [126], while the increase in squealer cavity width improves it [126]. The study conducted by Da Soghe et al [126] indicated that the best efficiency gain was achieved with the squealer depth of 15% of the blade thickness and with the squealer width of 80% of the blade thickness.…”

“…Increase in squealer cavity depth reduces performance [126], while the increase in squealer cavity width improves it [126]. The study conducted by Da Soghe et al [126] indicated that the best efficiency gain was achieved with the squealer depth of 15% of the blade thickness and with the squealer width of 80% of the blade thickness. The study of Li et al [129] indicated that the best efficiency gain is achieved with the squealer depth of three times the tip clearance (1.38 mm) when the squealer is as wide as possible.…”

“…Sometimes, ribs between the squealers are used. However, they have not shown any significant benefits in aerodynamic performance [126]. Numerical studies have found that openings in squealers on the blade suction side at the leading and trailing edges can be beneficial [127].…”

“…The effect of squealers on aerodynamic performance is connected to the operating conditions of a centrifugal compressor (improved performance at high flow rates, decreased performance at low flow rates) [126]. Increase in squealer cavity depth reduces performance [126], while the increase in squealer cavity width improves it [126].…”

Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance

“…They observed increase in energy coefficient and efficiency with squealer tips on pressure or suction surface. Recently Da Soghe et al [14] carried out numerical studies on the effects of various tip recessed geometries at two values of tip clearances on the performance of a transonic centrifugal compressor. Based on the results, further computations were carried out with a single rim tip squealer geometry, which had shown performance improvements for all the computed conditions.…”