Investigation for Loss Generation Mechanisms of Flow in Turbomachinery by Using Curved Square Duct (2nd Report, Influence of Cross-Sectional Aspect Ratio)

Investigation for Loss Generation Mechanisms of Flow in Turbomachinery by Using Curved Square Duct

“…The results in the present study and in the second report (2) imply the followings. The increase of α more restrains the increase of the loss for the case of R c = const., but more increases the loading coefficient A cps for the case of L c = const.…”

“…As described in the results for R a = 1.0, the loss caused by the passage vortex becomes predominant in the overall loss generation downstream of the bend due to the decline of passage vortex developed within the bend. However, the development of the passage vortex within the bend for R a = 3.0 is weaker than that for R a = 1.0 (2) . Thus, as known by the comparison between Figs.…”

“…3. In the second report (2) concerning the effects of cross-sectional aspect ratio R a (= S /H), it was clarified that the loss caused by the passage vortex was extremely increased by the decrease of R a lower than 2.0. Thus, in this study, the aspect ratio R a of curved duct was set to 1.0 and 3.0.…”

“…In addition, the effects of the inlet velocity profile as the aerodynamic parameter on the formation of passage vortex and the associated loss generation were examined in detail. The effects of the cross-sectional aspect ratio of the curved ducts as the geometrical parameter on them were clarified in the second report (2) . On the other hand, the several investigations (3) - (5) concerning the increase of blade loading for turbine cascades have been made in order to improve the performance characteristics of gas turbines.…”