2 edition of Influence of boundary condition in the stalling behviour of an axial flow compressor rotor. found in the catalog.
Influence of boundary condition in the stalling behviour of an axial flow compressor rotor.
Thesis (M.Sc.) - University of Birmingham, Dept of Mechanical Engineering.
comparison of all simulation was presented and the flow field would be analysed. 2 Rotor Geometries Definition Original Rotor Type A transonic axial compressor rotor, NASA Rotor 37 was used as original rotor type in this paper. The rotor 37 was designed by . Design And Development Of Transonic Axial Flow Compressor Rotor Blade 25 Figure 7 shows the comparative detailed streamline patterns in suction side of the rotor for various design speed at maximum efficiency condition. The streamlines discharged from the leading edge and the separation lines are created at the suction side boundary.
Gas turbine axial compressor blades may encounter damage during service for various reasons such as damage by debris from casing or foreign objects impacting the blades, typically near the rotor’s tip. This may lead to deterioration of performance and reduction in the surge margin. The damage breaks the cyclic symmetry of the rotor assembly thus computational fluid dynamics (CFD) simulations. Transonic Axial Flow Compressor Hanoca P*, Shobhavathy M T** out for the baseline configuration of the compressor stage having an axial blade spacing of 75% of the rotor tip axial chord. The steady flow computations have been carried out for four speeds namely 43%, 60%, 80% and 90% of the Towards the stall condition of the compressor, the.
boundary conditions used in Vahdati’s model (), they varied the cross section of the Laval nozzle during the surge cycle to control the system behavior. For the Rig stage research compressor from DLR, Giersch et al. () adopted the. intended to build understanding about the design methodology and flow field behavior of multi stage axial flow compressor. A three stage axial flow compressor, suitable for Small Gas Turbine (SGT) application, has been designed. The designed compressor stage is intended to deliver mass flow rate of kg/s, pressure ratio of.
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This situation is defined as the stall due to too small flow rates or choke due to too large flow rates. The stall conditions are the points at which the compressor cannot add enough energy to. In this study, the evolution of instability in a transonic axial flow compressor at different rotor speeds shows that at 65% of the design rotor speed, partial surge does not occur; at 78% of the.
The influence of reflecting boundary conditions on the blade modal force is studied by preventing wave reflection. Additionally, a 5-row simulation is studied to take an extra source of excitation force, the IGV row with the same blade count as the other stators, into consideration.
This paper describes a novel way of prescribing computational fluid dynamics (CFD) boundary conditions for axial-flow compressors. The approach is based on extending the standard single passage computational domain by adding an intake upstream and a variable nozzle downstream.
Such a route allows us to consider any point on a given speed characteristic by simply modifying the nozzle area, the actual boundary conditions Cited by: This paper describes a novel way of prescribing computational fluid dynamics (CFD) boundary conditions for axial-flow compressors.
The approach is based on extending the standard single passage computational domain by adding an intake upstream and a variable nozzle downstream. Such a route allows us to consider any point on a given speed characteristic by simply modifying the nozzle.
Chen Haixin et al.  simulated the flow in a transonic axial compressor NASA Rotor 37 with the help of in-house developed code. The Circumferential Grooves Casing Treatment (CGCT), used to find out improvement of the stall margin for axial flow compressor and the influence of the.
The axial position of this line, denoted x zs , moved upstream with decreasing flow coefficient in both the experiments and computations. The line was consistently located at the rotor leading edge plane at the stalling flow coefficient, regardless of inflow boundary condition.
Stall Inception and Development Process Due to Tip Leakage Flow in Axial Compressor Rotor Blades Row 13 March | Journal of Mechanics, Vol. 30, No. 3 Stator conditioning effects on steam turbine rotating instability.
Second, your inlet and outlet are close to the blades; the flow field is being artificially truncated by the boundary condition, causing the artificial walls to be erected where te solution wants to back flow.
You will likely need a better initial condition, better boundary conditions, farther boundary conditions, or some combination of all three.
Besides the outlet nonuniform flow field induced by the volute, the inlet nonuniform flow field also has a significant influence on the compressor performance and stall behaviors. He [ 25 ] computationally studied the rotating-stall inception in an axial compressor under the clean inlet, first- and second-mode inlet total pressure perturbations.
Gamache observed that inside a stall cell the flow is fully reversed whilst the mixed/inverting flow is present only in the thin boundary of the cell. It is then more important to accurately model the separated fully reversed flow as this has the greatest influence on the stalled performance. In a repeating stage compressor, it is assumed that after about the 4 th compressor stage, the endwall boundary layer shows no more significant growth for the downstream stages.
As (for sufficiently large aspect ratios) the chord length is the most relevant length scale for this problem, it is reasonable to assume, that this “equilibrium” boundary layer thickness scales with the average chord length of. Measurements in a stage gas turbine compressor provided detailed information about the unsteady flow behavior in a multi stage compressor influenced by different compressor loads.
For a long term investigation the stages 11 and 13 were equipped with wall mounted piezo-electric pressure sensors in the axial gaps between rotor and stator.
Another approach to control the flow near the rotor blade tip is based on the injection of high momentum fluid and/or bleed of low momen-tum fluid. The combination of injection and bleed leads to recircula-ting flow: the compressor static pressure rise induces a recirculation of high pressure flow from the rear to the front of a rotor.
This can. Example of complete compressor map with reverse flow and rotating stall characteristics and trajectory of rotating stall and surge. Both types of compressor stall can cause large damage to the engine, affect the mission (if, for example, the stalled engine must be turned off or kept in idle) or put the passengers in danger.
The flow in an axial compressor close to stall conditions is simulated by DDES calculations on two different geometrical models to investigate the influence imposing periodicity of different domain sizes on the flow. Time traces of integral forces are compared for both configurations.
Surge is an unsteady 1D phenomenon with mass flow oscillations in the axial direction, even the reversed flow inside the compressor at severe conditions.
Both rotating stall and surge can lead destructive to consequences to the compressor; however the appearance of the nonrecovery rotating stall in the aero-engine system, make it important to. The rotating stall behavior at two different compressor operating points was studied by considering two different variable-vane scheduling conditions for which experimental data were available.
In all cases, the rotating stall was initiated by introducing a small amount of geometric mistuning to the rotor blades. global compressor performance and detailed flow behaviour in the tip clearance and slot regions.
GEOMETRIC MODEL A transonic axial flow compressor rotor of NACA design  was selected for the present study. The compressor stage, designed for a pressure ratio of and an adiabatic efficiency of 89%, comprised 21 rotor.
NUMERICAL SIMULATION OF ROTATING STALL IN AN AXIAL COMPRESSOR F. Ginter, A. Ruprecht, E. Göde Institute of Fluid Mechanics and Hydraulic Machinery, University of Stuttgart Abstract: The flow instability “ rotating stall” is simulated for a one-stage water model of an axial compressor with 30 runner and 30 stator blades.
Furthermore, downstream boundary conditions are also unknown during rotating stall or surge and simulations become difficult.
This research presents unsteady time-accurate CFD analyses of compressor performance with tip curl blade damage in a single stage axial flow compressor and VSVs mal-schedule in a stage axial flow compressor.article aims to study the influence of probe-strut measuring positions on the aerodynamics of transonic speed axial flow compressor rotor.
The probe strut is modelled at rotor-upstream on different axial positions. The results are analysed with respect to the mass flow at which the rotor is near-stall.
The transition process from a diffuser rotating stall to a stage stall in a centrifugal compressor with a vaned diffuser was investigated by experimental and numerical analyses. From the velocity measurements, it was found that the rotating stall existed on the shroud side of the diffuser passage in the off-design flow condition.
The numerical results revealed the typical vortical structure .