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Showing 1 to 20 of 59 for “"secondary flows"”.
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Secondary flows in centrifugal compresser impellers
… flow. A wake flow was observed in all three flows and there were two major sources of the wake fluid. Firstly, from the separation of the shroud boundary layer and secondly, from the accumulation of low p* fluid from the other boundary layers by secondary flows. The results showed that the …
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The effects of secondary flows on the heat transfer to turbine nozzle endwall and rotor shroud.
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1979.
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Convective heat transfer in rotating, circular channels
… rotational speeds, as predicted through secondary flows caused by Coriolis forces. Moreover, the heat-transfer enhancement is found to be greater than the resulting increase in friction losses due to secondary flows.
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Multidisciplinary Optimization of Next-Generation Aero-Engine Fans
… and performances is to control and reduce the secondary flows that develop in their blade passages. Secondary flows reduce the pressure ratio and efficiency of aero-engine compressors, alter their operations at off-design conditions and shorthen the life of downstream components. The work of …
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Heat Transfer Performance Improvement Technologies for Hot Gas Path Components in Gas Turbines
… in the two-pass channel. The bend-induced secondary flows were observed to significantly affect the flow and heat transfer distribution in the 2nd pass. The thermal-hydraulic performance of V-shaped and 45° angled ribs were better than W-shaped and M-shaped ribs. The second section of the …
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Active Flow Control of a Boundary Layer Ingesting Serpentine Diffuser
… a thick ingested boundary layer creates strong secondary flows that lead to severe flow distortion at the engine face, increasing the possibility of engine surge. This study investigated the use of enabling active flow control methods to reduce engine-face distortion. An ejector-pump based …
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ENHANCEMENT OF CONVECTIVE HEAT TRANSFER IN INTERNAL FLOWS USING AN ELECTRICALLY-INDUCED CORONA JET
… and industrial research studies. Internal flows play a major role in many applications and different methods have been utilized to augment the heat transfer to internal flows. Secondary flows consume part of the kinetic energy of the flow and disturb the boundary layer. Inducing secondary …
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Characterization of performance-limiting flow mechanisms in a centrifugal compressor stage
… three-dimensional effects as source terms, these secondary flows are shown to detrimentally impact the diffuser pressure rise capability by accumulating high loss flow along the diffuser wall near the plane of symmetry between the vortices. This contributes to the extent and location of a large …
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The Effect of Density Ratio on Steep Injection Angle Purge Jet Cooling for a Converging Nozzle Guide Vane Endwall at Transonic Conditions
… adequately equipped to penetrate and suppress secondary flows, leaving the SS and PS largely exposed to high velocity and temperature mainstream gases. Conversely, it is observed that density ratio only marginally affects the high blowing condition, as the momentum effects become increasingly …
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Characteristics of the Liquid Film in Horizontal Two -Phase Flow
… tubes shows strong evidence of the impact of secondary flows on the liquid profile, and a theory for the origins of secondary flows under two-phase annular conditions is developed. Another important class of tubing analyzed are tubes with 0.2 mm microgrooves of varying helix angles in the …
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Aerodynamic Performance of High Turning Airfoils and the Effect of Endwall Contouring on Turbine Performance
… losses and associated issues. The strength of secondary flows is influenced by the upstream boundary layer thickness as well as the overall flow turning angle through the blade row. Secondary flows result in stagnation pressure loss which accounts for a considerable portion of the total …
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Experimental and numerical study on flow control using obliquely aligned elements.
… of the control elements to produce tailored secondary flows. Since the test coupon was of finite span, results demonstrate that controlled vortices can also be generated using the arrays. Additionally, CFD simulations were performed and compared to the experimental results using the …
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Broadband Noise Prediction of an Axial Compressor Operating at Low Reynolds Number
… of turbulence is then mainly limited to the secondary flows at the hub and tip gap which account for a large proportion of the wake turbulence. The secondary flows also feed turbulence into the blade profile boundary layers in these regions. A hybrid aeroacoustic prediction framework, based …
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The effects of temperature distortion on aerodynamics and low engine order forced response in axial turbines
… of the hot fluid affecting the development of secondary flows with consequent effects on enhanced local heat transfer and aerodynamic losses. The loss of symmetry has also been linked to the excitation of low-order nodal diameter assembly modes of the downstream rotor blades leading to …
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Investigation of the Effects of an Upstream Cavity on the Secondary Flow in Transonic Turbine Blade Passages with Endwall Contouring
… here aims to contribute to the understanding of secondary flows in modern high-pressure (HP) turbine blade passages. More specifically, it aims to improve the understanding of vortical structures near the endwall with respect to the presence of an upstream cavity that approximates the gap present …
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Parametric Investigation of the Combustor-Turbine Interface Leakage Geometry
… to improve efficiency and power output. Secondary flows develop as a result of a near-wall pressure gradient in the stagnating flow approaching the inlet nozzle guide vane as well as a strong cross-passage gradient within the passage. These flow structures enhance heat transfer and …
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CFD analysis and redesign of centrifugal impeller flows for rocket pumps
… Centrifugal impeller performance and secondary flows are discussed, and a summary of studies on the effects of impeller exit and diffuser inlet velocity distortion on diffuser performance is also presented. The flow calculation details and the results of the baseline impeller flow …
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