scholarly journals Causes for Turbomachinery Performance Deterioration

1988 ◽  
Author(s):  
W. Tabakoff
Keyword(s):  
Gas Turbine ◽  
Axial Flow ◽  
Leading Edge ◽  
Solid Particles ◽  
Two Stage ◽  
Axial Flow Compressor ◽  
Polluted Atmosphere ◽  
Performance Deterioration ◽  
Flow Compressor ◽  
Blunt Leading Edge

Turbines and compressors operating in polluted atmosphere with solid particles are subjected to performance deterioration. This paper presents an investigation carried out on two-stage gas turbine with blunt leading edge blades and on a single-stage axial flow compressor to study the effects of particulates and erosion on performance deterioration.

scholarly journals The Dynamics of Suspended Solid Particles in a Two Stage Gas Turbine

1986 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Suspended Solid ◽  
Solid Particles ◽  
Two Stage ◽  
Particle Momentum ◽  
Performance Deterioration ◽  
And Performance

Gas turbine engines operating in dusty environments are exposed to erosion and performance deterioration. In order to provide the basis for calculating the erosion and performance deterioration of turbines using pulverized coal, an investigation is undertaken to determine the three dimensional particle trajectories in a two stage turbine. The solution takes into account the influence of the variation in the three dimensional flow field. The change in particle momentum due to their collision with the turbine blades and casings is modeled using empirical equations derived from experimental Laser Doppler Velocimetry (LDV) measurements. The results show the three dimensional trajectory characteristics of the solid particles relative to the turbine blades. The results also show that the particle distribution in the flow field are determined by particle-blade impacts. The results obtained from this study indicate the turbine blade locations which are subjected to more blade impacts and hence more erosion damage.

Numerical Simulation of Steady Air Injection Flow Control Effects on a Transonic Axial Flow Compressor

2012 ◽  
Vol 224 ◽  
pp. 352-357
Author(s):  
Islem Benhegouga ◽  
Ce Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Leading Edge ◽  
Air Injection ◽  
Axial Flow Compressor ◽  
Blade Tip ◽  
Flow Compressor

In this work, steady air injection upstream of the blade leading edge was used in a transonic axial flow compressor, NASA rotor 37. The injectors were placed at 27 % upstream of the axial chord length at blade tip, the injection mass flow rate is 3% of the chock mass flow rate, and 3 yaw angles were used, respectively -20°, -30°, and -40°. Negative yaw angles were measured relative to the compressor face in opposite direction of rotational speeds. To reveal the mechanism, steady numerical simulations were performed using FINE/TURBO software package. The results show that the stall mass flow can be decreased about 2.5 %, and an increase in the total pressure ratio up to 0.5%.

Compressor Erosion and Performance Deterioration

1987 ◽  
Vol 109 (3) ◽  
pp. 297-306 ◽  
Author(s):  
W. Tabakoff
Keyword(s):  
Axial Flow ◽  
Solid Particles ◽  
Atmospheric Environment ◽  
Jet Engines ◽  
Particle Trajectories ◽  
Performance Deterioration ◽  
The Difference ◽  
And Performance ◽  
Flow Compressor ◽  
Particle Separator

Aircraft engines operating in areas where the atmosphere is polluted by small solid particles are typical examples of jet engines operating under hostile atmospheric environment. The particles may be different kinds of sand, volcanic ashes or others. Under these conditions, the gas and particles experience different degrees of turning as they flow through the engine. This is mainly due to the difference in their inertia. This paper presents the results of an investigation of the solid particle dynamics through a helicopter engine with inlet particle separator. The particle trajectories are computed in the inlet separator which is characterized by considerable hub and tip contouring and radial variation in the swirling vane shape. The nonseparated particle trajectories are determined through the deswirling vanes and the five stage axial flow compressor. The results from this study include the frequency of particle impacts and the erosion distribution on the blade surfaces.

Detection of a Rotating Stall Precursor in Isolated Axial Flow Compressor Rotors

1991 ◽  
Vol 113 (2) ◽  
pp. 281-287 ◽  
Author(s):  
M. Inoue ◽  
M. Kuroumaru ◽  
T. Iwamoto ◽  
Y. Ando
Keyword(s):  
Pressure Sensor ◽  
Pressure Fluctuation ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Statistical Characteristics ◽  
Flow Passage ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Stall Precursor

Statistical characteristics of pressure fluctuation on the casing wall of two axial flow compressor rotors have been investigated experimentally to find a precursor of rotating stall. Near stall, the casing wall pressure across a flow passage near the leading edge is characterized by a highly unsteady region where low-momentum fluid accumulates. The periodicity of the pressure fluctuation with blade spacing disappears and an alternative phenomenon comes into existence, which supports the disturbance propagating at a different speed from the rotor revolution. The precursor of rotating stall can be detected by monitoring collapse of the periodicity in the pressure fluctuation. To represent the periodicity qualitatively, a practical detection parameter has been proposed, which is easily obtained from signals of a single pressure sensor installed at an appropriate position on the casing wall during operation of a compressor.

scholarly journals Optimum Control of Variable Components in Aircraft Gas Turbine Engines Under Non-Stationary Flow Disturbances at the Inlet

1994 ◽  
Author(s):  
I. N. Egorov ◽  
G. V. Kreitinin
Keyword(s):  
Gas Turbine ◽  
Dynamic Control ◽  
Axial Flow ◽  
Stationary Flow ◽  
Turbine Engines ◽  
Stable Operation ◽  
Turbine Engine ◽  
Axial Flow Compressor ◽  
Flow Disturbances ◽  
Flow Compressor

A numerical method has been preposed to determine optimum laws to control gas turbine engine (CTE) variable components, including an independent control of blade rows in a multistage axial flow compressor under strong non-stationary flow disturbances at the inlet, optimum laws to control a turbofan under non-stationary thermal effects at the inlet have been obtained using mathematical models with various degree of filling in detail the flow in an engine flow path. There is shown a possibility to considerably increase a range of the CTE stable operation through the use of dynamic control of stator blades in a multistage axial flow compressor, also possibilities of practical use of optimum laws to control engine variable components in the system of preventing an unstable operation are being discussed.

Effects of tip clearance size on the unsteady flow behaviors and performance in a counter-rotating axial flow compressor

2017 ◽  
Vol 233 (3) ◽  
pp. 1059-1070 ◽  
Author(s):  
Xiaochen Mao ◽  
Bo Liu ◽  
Hang Zhao
Keyword(s):  
Unsteady Flow ◽  
Incidence Angle ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Flow Compressor

This paper presents the studies performed to better understand the effects of increased tip clearance size on the unsteady flow behaviors and overall performance under the rotor–rotor interaction environment in a counter-rotating axial flow compressor. The investigation method is based on the three-dimensional unsteady Reynolds-averaged Navier–Stokes simulations. The results show that the intensified tip leakage flow in front rotor (R1) caused by the increased tip clearance size will lead to the growth of incoming incidence angle near the tip of the rear rotor (R2). The increasing of double leakage flow range plays a significant role in the sensitivity of the efficiency to tip clearance size and its extent is enlarged gradually with the increase of tip clearance size. As the tip clearance size is increased to 1.5τ (τ represents the designed tip clearance size) from 0.5τ, the results of the fast Fourier transform for the static pressure near blade tip show that two other new fluctuating frequency components appear due to the happening of tip leakage flow self-unsteadiness in R1 and R2, respectively. Additionally, the fluctuating strength near the tip in R2 is significantly increased. However, both the overall fluctuation in R1 caused by the potential effect from downstream and the oscillation in the hub corner on the pressure side of R2 are decreased obviously. The relative inflow angle tends to increase when the incoming wakes and tip leakage flow from R1 encounter the blade leading edge of R2, which leads to the result that the trajectory of tip leakage flow is shifted more upstream.

Design and Development of a Two Stage Transonic Axial Flow Compressor

1996 ◽  
Author(s):  
Katsushi Nagai ◽  
Kazuaki Ikesawa ◽  
Takao Sugimoto ◽  
Toshinao Tanaka ◽  
Hiroshi Umino ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Design Method ◽  
Axial Flow ◽  
Test Facility ◽  
Blade Design ◽  
Two Stage ◽  
Circular Arc ◽  
Axial Flow Compressor ◽  
Transonic Compressor ◽  
Flow Compressor

A highly loaded two stage transonic axial flow compressor, which forms a front stages of a multi stage compressor for industrial gas turbines, has been designed and tested. Overall pressure ratio is 2.25 and the first stage rotor tip Mach number is 1.15. Two airfoil types, Double Circular Arc airfoil and Multi Circular Arc airfoil, were designed for a transonic rotor blade under the same condition. MCA blade design method was devised and introduced. The blade design relied heavily on CFD techniques using a Euler code and a Navier Stokes code to cope with a precise treatment. The rig test was conducted by our compressor test facility to verify a validity of the transonic compressor design method and to compare the performance of the DCA and the MCA airfoils. This report describes the aerodynamic design and the test results as well as the test facility and instrumentation.

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