3 edition of Unsteady analysis of rotor blade tip flow found in the catalog.
Unsteady analysis of rotor blade tip flow
by National Aeronautics and Space Administration, Scientific and Technical Information Branch, National Technical Information Service, distributor in [Washington, D.C.], Springfield, Va
Written in English
|Statement||B. Maskew and B.M. Rao.|
|Series||NASA contractor report -- NASA CR-3868.|
|Contributions||Rao, B. M., United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.|
|The Physical Object|
Based on Shear Stress Transport (SST) turbulence model for unsteady simulation of an axial-flow fan, this paper studies the time-frequency information in the hump region, and investigates the disturbance information of spike and modal wave under different flow coefficients based on continuous wavelet transform (CWT). The results show that before the hump point, the low-frequency modal wave. For steady analysis, the predicted results agree well with the experimental data for the estimation of compressor rotor global performance. For unsteady flow analysis, the unsteady flow nature caused by the breakdown of the tip leakage vortex in blade tip region in the transonic compressor rotor at near stall condition has been captured with a.
Reference 7 presents rotor-stator-interaction results ob-tained using the Euler equations. The various natural bound-ary conditions such as inlet, discharge, blade surface, and periodicity boundary conditions that are required for rotor-stator calculations are presented, and the unsteady flow through a . This study predicts, analyzes, and isolates the mechanisms of main rotor airloads, structural loads, and swashplate servo loads in a severe unsteady maneuver. The objective is, to develop a comprehensive transient rotor analysis for predicting maneuver loads. The main rotor structural loads encountered during unsteady maneuvers are important to size different critical components of the rotor.
() also found a tip flow instability on a low speed fan rig near the stall line and with a large tip clearance. This paper also presents the results of an unsteady CFD model that predicts a frequency of Hz compared to the measured value of Hz. Fig. 2. Strain gage response of first-stage rotor blades of compressor rig. The rotor blade has circular arc proﬁle sections designed by a quasi-three-dimensional method of Inoue et al. @15# on a forced vortex oper-ating condition and an axial inlet ﬂow condition. The number of blades is 5, and the blade thickness changes from 4 mm ~at rotor hub! to3mm~at rotor tip! proportionally. The blade tip section.
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Get this from a library. Unsteady analysis of rotor blade tip flow. [B Maskew; B M Rao; United States. National Aeronautics and Space Administration.
Scientific and Technical Information Branch.]. The geometry and flow conditions of the first stage turbine blade of GE’s E 3 engine with a tip clearance equal to 2% of the span were utilized. The upstream wake had both a total pressure and temperature deficit.
The rotor inlet conditions were determined from a steady analysis of the cooled upstream by: The first aim of this paper is to represent a unique work in providing unsteady data for the purpose of a CFD test case. Second, a detailed analysis of rotor-stator-interaction in a multistage compressor is performed by means of accompanying frequency analysis of the blading and the tip leakage flow for different indexing by: This study focuses on the physics of flow and heat transfer in the rotor tip, casing, and hub regions.
The simulation was performed using the unsteady Reynolds-averaged Navier–Stokes code MSU-TURBO. A low Reynolds number k- ε model was utilized to model turbulence. The rotor blade in question has a tip gap height of % of the blade by: The hub leakage and the tip clearance lead to the tip cavitation and non-uniform flow.
The rotor-stator interaction induces unsteady flow and pressure fluctuation, as one of the main causes of vibration, noise, fissures, blade cracking and guide vanes bearing by: The rotor tip flow unsteadiness is induced by the periodic passage of the rotor blades, with an intensity dependent on the tip gap geometry.
Hence, the understanding of the physics is of paramount importance to develop appropriate predictive tools and improve the cooling schemes. Changes in HPT tip clearance during a given mission profile  Flow in turbine is inherently highly unsteady due to the relative motion between rotor and stator blade rows.
The effect of rotor - stator interaction is too important to be neglected, such as the interaction between the secondary flow/tip clearance flow vortices and the periodic wakes or potential field from upstream and downstream blade rows. A rapidly moving rotor blade in hover is an unsteady object which nonetheless has a static flow in the blade reference system, and this could be frozen using the lifetime method, see Fig.
Here the sparse pressure instrumentation of the rotor blade, described in the previous section and shown in Fig. 3, is significantly augmented by the use of pressure sensitive paint. It identifies the interaction between the tip clearance flow and the pressure pulses, induced on the rotor blade pressure surface by the upstream wakes, as the cause for the observed effects.
The direct effect of the interaction is a decrease in the time-average double-leakage flow through the tip clearance gap so that the stream-wise defect of. The case chosen for this study is the rotor blade of Garett's TFE HP turbine.
Duma and eoworkers have performed extensive vane and blade surface heat transfer measurements on this turbine. They also measured the rate of heat transfer on the tip along the mean camber line of the rotor blade as well as along the shroud. In this section, the pressure fluctuations around the rotor phase locked each front and rear rotor’s rotations are shown and the unsteady flow condition associated with the wake, potential interference and leakage flow from the blade tip clearance are discussed by the unsteady numerical analysis.
Mailach et al. and März et al. described the unsteady fluctuation of blade tip vortex as “rotating instability (RI)”, which is characterized by the similar frequency (approximately BPF) proposed by Geng et al., and the RI circumferentially propagates at a speed of 50%–60% of rotor velocity.
Helicopter rotor blade computation in unsteady flows using moving overset grids. Unsteady rotor flow analysis using a diagonally implicit harmonic balance method and an overset mesh topology. BILU implicit multiblock Euler/Navier–Stokes simulation for rotor tip vortex and wake convection.
SPECTRAL ANALYSIS OF UNSTEADY FLOW SIMULATION IN A SMALL VAWT The rotor blades are non-linearly twisted = freestream velocity U tip = velocity at the rotor tip R = radial direction R tip. Abstract. The tip leakage flow losses of the shrouded rotor blade contribute significantly to overall losses of the turbine stage.
Effects of the shrouded rotor blade tip leakage flow in stator blade/shrouded rotor blade/stator blade on the aerodynamic performance of a axial turbine stage were numerical investigated using commercial CFD software CFX-TASCflow.
A good design of the turbine blade consists the determination of steady loads acting on the blade and stressing due to them, determination of unsteady forces due to stage flow interaction. including comparisons to recently acquired measurements of unsteady loads on main rotor blades.
Finally, the priorities currently envisioned for follow-on work to build on the present code for still more advanced implementations will be summarized. Background As noted, the motivation for the work described here was the analysis of rotor. Then, rotor blade tip shapes that have been used, or suggested for use, on past and present rotorcraft are examined to obtain a better understanding of the helicopter tip design problem.
Influence of various design parameters and unsteady flow on the fluid–structure interaction of a lightly cambered blade in a cascade Aerospace Science and Technology, Vol. 65 On the relation between friction losses and pressure pulsations caused by Rotor Stator interaction on the Francis turbine.
An analytical approach is presented to model the broadband unsteady force cross-correlations exerted on a rotor due to a spatially homogeneous turbulent inflow. In addition, the rotor unsteady force cross-correlation matrix is treated as a set of correlated, compact dipole acoustic sources to predict the low-frequency radiated sound field of a subsonic rotor ingesting a turbulent flow.
FoM for PSP model rotor at blade-tip Mach number of As shown the AD4 model is a good approximation of the CFD simulation results, with only slight under-prediction of the loads near the tip. Unsteady Analysis on the Effects of Tip Clearance Height on Hot Streak Migration Across Rotor Blade Tip Clearance 28 February | Journal of Engineering for Gas Turbines and Power, Vol.No.
8 Aerodynamic Interactions Between a High-Pressure Turbine and the .Though steady formulations are typically used for conventional gas turbines, unsteady flow can be caused by potential field interactions, wake-blade interactions, rotor-stator shock interaction.