Experimental Investigations of Stall Flutter in a Transonic Cascade

1999 ◽  
Author(s):  
Karsten Ellenberger ◽  
Heinz E. Gallus
Keyword(s):  
Steady State ◽  
Gas Turbines ◽  
Flow Behavior ◽  
Dynamic Pressure ◽  
Experimental Investigations ◽  
Compressor Blades ◽  
Pressure Transducers ◽  
Oil Flow ◽  
Mach Numbers ◽  
Stall Flutter

The design of modern gas turbines is more and more based on flow simulations by numerical calculation models. Due to the different influence parameters the development and verification of these codes requires detailed data bases, which can only be provided by experimental investigations. The demand of increasing power density leads to higher Mach Numbers up to transonic ranges. Due to the thin blade profiles the risk of stall flutter becomes an extraordinary point of interest. Therefore, in a transonic wind tunnel a cascade of nine compressor blades designed by MTU Munich were investigated at different inlet Mach numbers and incidence angles. To get information about flow behavior at steady state, profile pressure distribution was measured at midspan with pressure taps on profile surface. In order to provide information about the overall flow field oil flow visualization and Schlieren technique were applied for the investigation at steady state. For flutter simulation the blade in the middle position of the cascade was forced to torsional oscillating movement by an electromagnetic shaker system with a frequency of f = 310.0 Hz. The flow behavior with oscillating and fixed center blade was investigated at midspan by means of dynamic pressure transducers and hot films glued on profile probes. The results of these investigations are presented in this paper especially up to the appearance of stall flutter.

scholarly journals Design and Test of a New Axial Compressor for the Nuovo Pignone Heavy Duty Gas Turbines

1996 ◽  
Author(s):  
Erio Benvenuti
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Leading Edge ◽  
Meridional Flow ◽  
Heavy Duty ◽  
Pressure Transducers ◽  
Easy Integration

This axial compressor design was primarily focused to increase the power rating of the current Nuovo Pignone PGT10 Heavy-Duty gas turbine by 10%. In addition, the new 11-stage design favourably compares with the existing 17-stage compressor in terms of simplicity and cost. By seating the flowpath and blade geometry, the new aerodynamic design can be applied to gas turbines with different power ratings as well. The reduction in the stage number was achieved primarily through the meridional flow-path redesign. The resulting higher blade peripheral speeds achieve larger stage pressure ratios without increasing the aerodynamic loadings. Wide chord blades keep the overall length unchanged thus assuring easy integration with other existing components. The compressor performance map was extensively checked over the speed range required for two-shaft gas turbines. The prototype unit was installed on a special PGT10 gas turbine setup, that permitted the control of pressure ratio independently from the turbine matching requirements. The flowpath instrumentation included strain-gages, dynamic pressure transducers and stator vane leading edge aerodynamic probes to determine individual stage characteristics. The general blading vibratory behavior was proved fully satisfactory. With minor adjustments to the variable stator settings the front stage aerodynamic matching was optimized and the design performance was achieved.

scholarly journals Experimental Methods Applied in a Study of Stall Flutter in an Axial Flow Fan

2004 ◽  
Vol 11 (5-6) ◽  
pp. 597-613 ◽  
Author(s):  
John D. Gill ◽  
Vincent R. Capece ◽  
Ronald B. Fost
Keyword(s):  
Experimental Data ◽  
Dynamic Pressure ◽  
Axial Flow ◽  
Leading Edge ◽  
Axial Flow Fan ◽  
Pressure Transducers ◽  
High Frequency Response ◽  
Stall Flutter ◽  
Response Pressure ◽  
Flutter Testing

Flutter testing is an integral part of aircraft gas turbine engine development. In typical flutter testing blade mounted sensors in the form of strain gages and casing mounted sensors in the form of light probes (NSMS) are used. Casing mounted sensors have the advantage of being non-intrusive and can detect the vibratory response of each rotating blade. Other types of casing mounted sensors can also be used to detect flutter of rotating blades. In this investigation casing mounted high frequency response pressure transducers are used to characterize the part-speed stall flutter response of a single stage unshrouded axial-flow fan. These dynamic pressure transducers are evenly spaced around the circumference at a constant axial location upstream of the fan blade leading edge plane. The pre-recorded experimental data at 70% corrected speed is analyzed for the case where the fan is back-pressured into the stall flutter zone. The experimental data is analyzed using two probe and multi-probe techniques. The analysis techniques for each method are presented. Results from these two analysis methods indicate that flutter occurred at a frequency of 411 Hz with a dominant nodal diameter of 2. The multi-probe analysis technique is a valuable method that can be used to investigate the initiation of flutter in turbomachines.

Design and Test of a New Axial Compressor for the Nuovo Pignone Heavy-Duty Gas Turbines

1997 ◽  
Vol 119 (3) ◽  
pp. 633-639 ◽  
Author(s):  
Erio Benvenuti
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Leading Edge ◽  
Heavy Duty ◽  
Pressure Transducers ◽  
Heavy Duty Gas Turbine ◽  
Easy Integration

This axial compressor design was primarily focused to increase the power rating of the current Nuovo Pignone PGT10 Heavy-Duty gas turbine by 10 percent. In addition, the new 11-stage design favorably compares with the existing 17-stage compressor in terms of simplicity and cost. By scaling the flowpath and blade geometry, the new aerodynamic design can be applied to gas turbines with different power ratings as well. The reduction in the stage number was achieved primarily through the meridional flowpath redesign. The resulting higher blade peripheral speeds achieve larger stage pressure ratios without increasing the aerodynamic loadings. Wide chord blades keep the overall length unchanged thus assuring easy integration with other existing components. The compressor performance map was extensively checked over the speed range required for two-shaft gas turbines. The prototype unit was installed on a special PGT10 gas turbine setup, that permitted the control of pressure ratio independently from the turbine matching requirements. The flowpath instrumentation included strain gages, dynamic pressure transducers, and stator vane leading edge aerodynamic probes to determine individual stage characteristics. The general blading vibratory behavior was proved fully satisfactory. With minor adjustments to the variable stator settings, the front stage aerodynamic matching was optimized and the design performance was achieved.

Effect of Liquid Level on Gas Carry-Under in GLCC Compact Separators

2018 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Swirling Flow ◽  
Flow Behavior ◽  
Operating Conditions ◽  
Liquid Level ◽  
Experimental Investigations ◽  
Level Control ◽  
Oil Flow ◽  
Control Configuration ◽  
Carry Over ◽  
The Stability

Gas Carry-Under (GCU) is one of the two undesirable phenomena that occurs in the GLCC©1 (Gas-Liquid Cylindrical Cyclone) separators. Initial studies have shown that maintaining liquid level below the inlet of the GLCC© under control configuration affects the GCU in GLCC©. Also, it has been hypothesized that effective formation of vortex that is formed in the lower part of the GLCC©, or a stable gas core enhances the separation of gas entrained in the liquid. However, there has not been a systematic study on the effect of liquid level and the stability of the vortex on the GCU. This detailed and extensive experimental study attempts to fill that gap, investigating the effect of different liquid levels maintained below the inlet on the GCU. These studies are performed under the NOC (Normal operating Conditions) below the OPEN for liquid carry-over using control configuration to maintain the liquid level in the GLCC©. This study focuses on measuring the cumulative GCU in the liquid leg of the GLCC© over a period of time. The experimental investigations for GCU are conducted in a state of the art experimental facility for air-water and air-oil flow incorporating pressure and level control configurations. The experiments were carried out using a 3″ diameter GLCC© equipped with gas trap sections to measure simultaneously the GCU in the liquid leg of the GLCC©. The equilibrium liquid level is controlled at 4 different settings starting at 6″ below the GLCC© inlet and increasing to 2 feet below the inlet. It has been observed that the liquid level has tremendous effect on the complex swirling flow behavior in the lower part of the GLCC© and vortex stability, which in turn affects the GCU in the liquid leg of the GLCC©. Also, it has been noted that the liquid level has a significant effect on the Gas Void-Fraction in the liquid leg of the GLCC©, which is a critical parameter for multiphase pump operations.

Steady-State Flow Behavior of CO2 Foam

2004 ◽  
Author(s):  
J.S. Kim ◽  
Y. Dong ◽  
W.R. Rossen
Keyword(s):  
Steady State ◽  
Flow Behavior ◽  
Steady State Flow ◽  
State Flow ◽  
Co2 Foam

Experimental Evaluation of Compressor Blade Fouling

2016 ◽  
Author(s):  
Rainer Kurz ◽  
Grant Musgrove ◽  
Klaus Brun
Keyword(s):  
Boundary Layer ◽  
Gas Turbines ◽  
Blade Surface ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Compressor Blades ◽  
Performance Deterioration ◽  
Quantitative Results ◽  
The Impact ◽  
Dust Retention

Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Experimental and simulation data are available for the impact of specified amounts of fouling on performance, as well as the amount of foulants entering the engine for defined air filtration systems and ambient conditions. This study provides experimental data on the amount of foulants in the air that actually stick to a blade surface for different conditions of the blade surface. Quantitative results both indicate the amount of dust as well as the distribution of dust on the airfoil, for a dry airfoil, as well as airfoils that were wet from ingested water, as well as different types of oil. The retention patterns are correlated with the boundary layer shear stress. The tests show the higher dust retention from wet surfaces compared to dry surfaces. They also provide information about the behavior of the particles after they impact on the blade surface, showing that for a certain amount of wet film thickness, the shear forces actually wash the dust downstream, and off the airfoil. Further, the effect of particle agglomeration of particles to form larger clusters was observed, which would explain the disproportional impact of very small particles on boundary layer losses.

Steady State Detection in Industrial Gas Turbines for Condition Monitoring and Diagnostics Applications

2014 ◽  
Author(s):  
Cesar Celis ◽  
Érica Xavier ◽  
Tairo Teixeira ◽  
Gustavo R. S. Pinto
Keyword(s):  
Steady State ◽  
Condition Monitoring ◽  
Gas Turbines ◽  
Signal Analysis ◽  
Operating Regime ◽  
State Detection ◽  
Industrial Gas Turbines ◽  
Monitoring And Diagnostics ◽  
Operating Regimes

This work describes the development and implementation of a signal analysis module which allows the reliable detection of operating regimes in industrial gas turbines. Its use is intended for steady state-based condition monitoring and diagnostics systems. This type of systems requires the determination of the operating regime of the equipment, in this particular case, of the industrial gas turbine. After a brief introduction the context in which the signal analysis module is developed is highlighted. Next the state of the art of the different methodologies used for steady state detection in equipment is summarized. A detailed description of the signal analysis module developed, including its different sub systems and the main hypotheses considered during its development, is shown to follow. Finally the main results obtained through the use of the module developed are presented and discussed. The results obtained emphasize the adequacy of this type of procedures for the determination of operating regimes in industrial gas turbines.

Experimental and Numerical Analyses of a Pressurized Air Receiver for Solar-Driven Gas Turbines

2010 ◽  
Author(s):  
Illias Hischier ◽  
Pascal Leumann ◽  
Aldo Steinfeld
Keyword(s):  
Power Generation ◽  
Monte Carlo ◽  
Steady State ◽  
Gas Turbines ◽  
Porous Ceramic ◽  
Operating Pressure ◽  
Radiative Fluxes ◽  
Monte Carlo Techniques ◽  
Concentrated Solar Radiation ◽  
Solar Receiver

A high-temperature pressurized air-based receiver for power generation via solar-driven gas turbines is experimentally and theoretically examined. It consists of an annular reticulate porous ceramic (RPC) foam concentric with an inner cylindrical cavity-receiver exposed to concentrated solar radiation. Absorbed heat is transferred by combined conduction, radiation, and convection to the pressurized air flowing across the RPC. The governing steady-state mass, momentum and energy conservation equations are formulated and solved numerically by coupled Finite Volume and Monte Carlo techniques. Validation is accomplished with experimental results using a 1 kW solar receiver prototype subjected to average solar radiative fluxes in the range 1870–4360 kW m−2. Experimentation was carried out with air and helium as working fluids, heated from ambient temperature up to 1335 K at an absolute operating pressure of 5 bars.

Life Prediction of Power Turbine Components for High Exhaust Back Pressure Applications: Part I — Disks

2015 ◽  
Author(s):  
Dipankar Dua ◽  
Brahmaji Vasantharao
Keyword(s):  
Steady State ◽  
Secondary Flow ◽  
Gas Turbines ◽  
Life Prediction ◽  
Creep Damage ◽  
Back Pressure ◽  
System Level ◽  
Cyclic Life ◽  
Power Turbine ◽  
The Impact

Industrial and aeroderivative gas turbines when used in CHP and CCPP applications typically experience an increased exhaust back pressure due to pressure losses from the downstream balance-of-plant systems. This increased back pressure on the power turbine results not only in decreased thermodynamic performance but also changes power turbine secondary flow characteristics thus impacting lives of rotating and stationary components of the power turbine. This Paper discusses the Impact to Fatigue and Creep life of free power turbine disks subjected to high back pressure applications using Siemens Energy approach. Steady State and Transient stress fields have been calculated using finite element method. New Lifing Correlation [1] Criteria has been used to estimate Predicted Safe Cyclic Life (PSCL) of the disks. Walker Strain Initiation model [1] is utilized to predict cycles to crack initiation and a fracture mechanics based approach is used to estimate propagation life. Hyperbolic Tangent Model [2] has been used to estimate creep damage of the disks. Steady state and transient temperature fields in the disks are highly dependent on the secondary air flows and cavity dynamics thus directly impacting the Predicted Safe Cyclic Life and Overall Creep Damage. A System-level power turbine secondary flow analyses was carried out with and without high back pressure. In addition, numerical simulations were performed to understand the cavity flow dynamics. These results have been used to perform a sensitivity study on disk temperature distribution and understand the impact of various back pressure levels on turbine disk lives. The Steady Sate and Transient Thermal predictions were validated using full-scale engine test and have been found to correlate well with the test results. The Life Prediction Study shows that the impact on PSCL and Overall Creep damage for high back pressure applications meets the product design standards.

Retraction note to: Characterization of coconut oil flow behavior

2021 ◽  
Author(s):  
Vinod Dhaygude ◽  
Anita Soós ◽  
Réka Juhász ◽  
László Somogyi
Keyword(s):  
Flow Behavior ◽  
Coconut Oil ◽  
Oil Flow
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