Large Eddy Simulations of Film-Cooling Flows With a Micro-Ramp Vortex GeneratorJournal of Turbomachinery - Tập 135 Số 1 - 2013
Aaron Shinn, S. P. Vanka
Large eddy simulations were performed to study the effect of a micro-ramp on an inclined turbulent jet interacting with a cross-flow in a film-cooling configuration. The micro-ramp vortex generator is placed downstream of the film-cooling jet. Changes in vortex structure and film-cooling effectiveness are evaluated. Coherent turbulent structures characteristic of a jet in a cross-flow are ...... hiện toàn bộ
Detailed Boundary Layer Measurements on a Transonic Turbine CascadeJournal of Turbomachinery - Tập 114 Số 1 - Trang 163-172 - 1992
D. J. Mee, N. C. Baines, M. L. G. Oldfield
The boundary layers of a transonic turbine blade have been measured in detail. The full velocity profiles have been measured at a number of stations on both the suction and pressure surfaces, at conditions representative of engine operation, using a Pilot traverse technique and a large-scale (300 mm chord) linear cascade. This information has made it possible to follow the development of t...... hiện toàn bộ
Stall, Surge, and 75 Years of ResearchJournal of Turbomachinery - Tập 138 Số 1 - 2016
I. J. Day
Work on rotating stall and its related disturbances have been in progress since the Second World War. During this period, certain “hot topics” have come to the fore—mostly in response to pressing problems associated with new engine designs. This paper will take a semihistorical look at some of these fields of study (stall, surge, active control, rotating instabilities, etc.) and will exami...... hiện toàn bộ
Aeroelasticity at Reversed Flow Conditions — Part II: Application to Compressor SurgeJournal of Turbomachinery - Tập 134 Số 6 - 2012
Harald Schoenenborn, Thomas Breuer
The prediction of blade loads during surge is still a challenging task. In the literature, the blade loading during surge is often referred to as “surge load,” which suggests that there is a single source of blade loading. In the second part of our paper it is shown that, in reality, the “surge load” may consist of two physically different mechanisms: the pressure shock when the pressure b...... hiện toàn bộ
Poststall Behavior of a Multistage High Speed Compressor at Off-Design ConditionsJournal of Turbomachinery - Tập 140 Số 12 - 2018
Fanzhou Zhao, John A. Dodds, Mehdi Vahdati
Stall followed by surge in a high speed compressor can lead to violent disruption of flow, damage to the blade structures and, eventually, engine shutdown. Knowledge of unsteady blade loading during such events is crucial in determining the aeroelastic stability of blade structures; experimental test of such events is, however, significantly limited by the potential risk and cost associate...... hiện toàn bộ
Origins and Structure of Spike-Type Rotating StallJournal of Turbomachinery - Tập 137 Số 5 - 2015
Graham Pullan, A. Young, I. J. Day, E. M. Greitzer, Z. S. Spakovszky
In this paper, we describe the structures that produce a spike-type route to rotating stall and explain the physical mechanism for their formation. The descriptions and explanations are based on numerical simulations, complemented and corroborated by experiments. It is found that spikes are caused by a separation at the leading edge due to high incidence. The separation gives rise to shedd...... hiện toàn bộ
Stall and Recovery Process of a Transonic Fan With and Without Inlet DistortionJournal of Turbomachinery - Tập 142 Số 1 - 2020
Wenqiang Zhang, Mehdi Vahdati
Abstract
The aim of this research is to study the stall and recovery behavior of a transonic fan stage with and without inlet distortion. For this purpose, simulations of the stall and recovery process of NASA stage 67 are performed with clean and distorted inflow conditions. The rotor is pushed into stall by closing the exit nozzle. It is shown that...... hiện toàn bộ
Validation of Numerical Simulation for Rotating Stall in a Transonic FanJournal of Turbomachinery - Tập 135 Số 2 - 2013
Minsuk Choi, Nigel Smith, Mehdi Vahdati
This paper addresses a comparison of numerical stall simulations with experimental data at 60% (subsonic) and 95% (supersonic) of the design speed in a modern transonic fan rig. The unsteady static pressures were obtained with high frequency Kulite transducers mounted on the casing upstream and downstream of the fan. The casing pressure variation was clearly visible in the measurements whe...... hiện toàn bộ
The Role of Tip Leakage Flow in Spike-Type Rotating Stall InceptionJournal of Turbomachinery - Tập 141 Số 6 - 2019
M. Hewkin-Smith, Graham Pullan, S. D. Grimshaw, E. M. Greitzer, Z. S. Spakovszky
This paper describes the role of tip leakage flow in creating the leading edge separation necessary for the onset of spike-type compressor rotating stall. A series of unsteady multipassage simulations, supported by experimental data, are used to define and illustrate the two competing mechanisms that cause the high incidence responsible for this separation: blockage from a casing-suction-s...... hiện toàn bộ