Compressor Blade Vibration Measurements Using Blade Image Velocimetry

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Paul L. Mikrut ◽  
Scott C. Morris ◽  
Joshua D. Cameron
Keyword(s):  
Mass Flow Rate ◽  
Flow Rate ◽  
Measurement Technique ◽  
Vibration Amplitude ◽  
Axial Compressor ◽  
Compressor Blade ◽  
Shaft Speed ◽  
Blade Vibration ◽  
Air Mass ◽  
Image Velocimetry

This paper discusses the application of a novel vibration measurement technique, termed blade image velocimetry (BIV), to a high-speed axial compressor. Measurements of compressor blade vibration can be difficult to obtain and are critical to aeromechanical design validation. The measurement technique discussed in this paper used a commercial particle image velocimetry (PIV) system and was developed as an alternative to conventional measurement techniques such as strain gages and blade tip timing (BTT). The measurement principles and error analysis are reviewed. Methods for estimating the magnitude of random noise corrupting the measurement and validating the vibration amplitude estimates are presented. The technique was validated using a 1.5 stage axial compressor operating at low shaft speed, where it measured the tip velocity to within 0.02% of the true value. The technique was then used to investigate blade vibration at high shaft speed. Low amplitude vibrations in first bending and first torsion were discovered when the compressor was operated at design air-mass flow rate. These vibrations had a maximum tip deflection of 15μm for bending and 7μm for torsion. The vibration amplitude for first bending and first torsion tripled when the compressor was operated at low air mass-flow rate, corresponding to deep stall. Furthermore, excitation of the third eigenmode was also measured. The maximum tip deflections of the first three eigenmodes when the compressor was operated at deep stall were 47μm, 27μm, and 15μm, respectively.

Comprehensive Performance Improvement for a 16-Stage Axial Compressor

2021 ◽  
Author(s):  
Grigorii Popov ◽  
Maxim Miheev ◽  
Alexey Vorobyev ◽  
Oleg Baturin ◽  
Vasilii Zubanov
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Design Parameters ◽  
Air Mass ◽  
Stability Margins ◽  
Gas Dynamic ◽  
Low Efficiency

Abstract The paper describes the process of gas-dynamic modernization of a 16-stage axial compressor of an industrial gas turbine unit. Tests of the baseline variant of the compressor revealed a significant shortfall of efficiency, pressure ratio, and stability margins. In addition, the ongoing work on the modernization of the entire engine sets the task to the authors of not just achieving design parameters but significantly exceeding them (air mass flow rate by 6%, pressure ratio by 2%, adiabatic efficiency by 1% relative to the design values). To achieve these goals, a numerical model of the compressor was developed and validated. The characteristics obtained with its help were carefully analyzed. It was found that the front stage group has low efficiency, and the rear stage group is significantly oversized in terms of mass flow rate. Modernization works were significantly hampered by the presence of many stages and many independent variables. For this reason, the problem was solved in several stages. A separate modernization of the first and rear groups of stages was performed. Moreover, methods of mathematical optimization were used when developing the rear block of 10 stages. Then the working processes of the compressor parts were matched. As a result of the research, a variant was found to modernize the existing 16-stage axial compressor, providing an increase in the air mass flow rate by 18%, adiabatic efficiency by 3.5%, and margins of gas-dynamic stability up to 16%.

Numerical Simulation of the Performance of an Axial Compressor Operating With Supercritical Carbon Dioxide

2018 ◽  
Author(s):  
Jinlan Gou ◽  
Wei Wang ◽  
Can Ma ◽  
Yong Li ◽  
Yuansheng Lin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Numerical Simulation ◽  
Supercritical Carbon Dioxide ◽  
Critical Point ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Compressor ◽  
Brayton Cycle ◽  
Supercritical Carbon

Using supercritical carbon dioxide (SCO2) as the working fluid of a closed Brayton cycle gas turbine is widely recognized nowadays, because of its compact layout and high efficiency for modest turbine inlet temperature. It is an attractive option for geothermal, nuclear and solar energy conversion. Compressor is one of the key components for the supercritical carbon dioxide Brayton cycle. With established or developing small power supercritical carbon dioxide test loop, centrifugal compressor with small mass flow rate is mainly investigated and manufactured in the literature; however, nuclear energy conversion contains more power, and axial compressor is preferred to provide SCO2 compression with larger mass flow rate which is less studied in the literature. The performance of the axial supercritical carbon dioxide compressor is investigated in the current work. An axial supercritical carbon dioxide compressor with mass flow rate of 1000kg/s is designed. The thermodynamic region of the carbon dioxide is slightly above the vapor-liquid critical point with inlet total temperature 310K and total pressure 9MPa. Numerical simulation is then conducted to assess this axial compressor with look-up table adopted to handle the nonlinear variation property of supercritical carbon dioxide near the critical point. The results show that the performance of the design point of the designed axial compressor matches the primary target. Small corner separation occurs near the hub, and the flow motion of the tip leakage fluid is similar with the well-studied air compressor. Violent property variation near the critical point creates troubles for convergence near the stall condition, and the stall mechanism predictions are more difficult for the axial supercritical carbon dioxide compressor.

Stall Warning Using the Rotor Tip Pressure in a Transonic Axial Compressor With Circumferential Grooves

2018 ◽  
Author(s):  
Byeung Jun Lim ◽  
Tae Choon Park ◽  
Young Seok Kang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Single Stage ◽  
Stall Inception ◽  
Casing Treatment ◽  
Stall Warning ◽  
Transonic Axial Compressor

In this study, characteristics of stall inception in a single-stage transonic axial compressor with circumferential grooves casing treatment were investigated experimentally. Additionally, the characteristic of increasing irregularity in the pressure inside circumferential grooves as the compressor approaches the stall limit was applied to the stall warning method. Spike-type rotating stall was observed in the single-stage transonic axial compressor with smooth casing. When circumferential grooves were applied, the stall inception was suppressed and the operating point of the compressor moved to lower flow rate than the stall limit. A spike-like disturbance was developed into a rotating stall cell and then the Helmholtz perturbation was overlapped on it at N = 80%. At N = 70 %, the Helmholtz perturbation was observed first and the amplitude of the wave gradually increased as mass flow rate decreased. At N = 60%, spike type stall inceptions were observed intermittently and then developed into continuous rotating stall at lower mass flow rate. Pressure measured at the bottom of circumferential grooves showed that the level of irregularity of pressure increased as flow rate decreased. Based on the characteristic of increasing irregularity of the pressure signals inside the circumferential grooves as stall approaches, an autocorrelation technique was applied to the stall warning. This technique could be used to provide warning against stall and estimate real-time stall margins in compressors with casing treatments.

Visualization and Time-Resolved Particle Image Velocimetry Measurements of the Flow in the Tip Region of a Subsonic Compressor Rotor

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
David Tan ◽  
Yuanchao Li ◽  
Ian Wilkes ◽  
Rinaldo L. Miorini ◽  
Joseph Katz
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Axial Compressor ◽  
Time Resolved ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Direct Measurements ◽  
Image Velocimetry ◽  
The One ◽  
And Behavior

A new optically index matched facility has been constructed to investigate tip flows in compressor-like settings. The blades of the one and a half stage compressor have the same geometry, but lower aspect ratio as the inlet guide vanes (IGVs) and the first stage of the low-speed axial compressor (LSAC) facility at NASA Glenn. With transparent blades and casings, the new setup enables unobstructed velocity measurements at any point within the tip region and is designed to facilitate direct measurements of effects of casing treatments on the flow structure. We start with a smooth endwall casing. High speed movies of cavitation and time-resolved PIV measurements have been used to characterize the location, trajectory, and behavior of the tip leakage vortex (TLV) for two flow rates, the lower one representing prestall conditions. Results of both methods show consistent trends. As the flow rate is reduced, TLV rollup occurs further upstream, and its initial orientation becomes more circumferential. At prestall conditions, the TLV is initially aligned slightly upstream of the rotor passage, and subsequently forced downstream. Within the passage, the TLV breaks up into a large number of vortex fragments, which occupy a broad area. Consequently, the cavitation in the TLV core disappears. With decreasing flow rate, this phenomenon becomes more abrupt, occurs further upstream, and the fragments occupy a larger area.

Heat Transfer and Flow Friction Characteristics for Compact Cold Plates

2003 ◽  
Vol 125 (1) ◽  
pp. 104-113 ◽  
Author(s):  
Chang-Yuan Liu ◽  
Ying-Huei Hung
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Thermal Resistance ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Average Nusselt Number ◽  
Cold Plate ◽  
Air Mass

Both experimental and theoretical investigations on the heat transfer and flow friction characteristics of compact cold plates have been performed. From the results, the local and average temperature rises on the cold plate surface increase with increasing chip heat flux or decreasing air mass flow rate. Besides, the effect of chip heat flux on the thermal resistance of cold plate is insignificant; while the thermal resistance of cold plate decreases with increasing air mass flow rate. Three empirical correlations of thermal resistance in terms of air mass flow rate with a power of −0.228 are presented. As for average Nusselt number, the effect of chip heat flux on the average Nusselt number is insignificant; while the average Nusselt number of the cold plate increases with increasing Reynolds number. An empirical relationship between Nu¯cp and Re can be correlated. In the flow frictional aspect, the overall pressure drop of the cold plate increases with increasing air mass flow rate; while it is insignificantly affected by chip heat flux. An empirical correlation of the overall pressure drop in terms of air mass flow rate with a power of 1.265 is presented. Finally, both heat transfer performance factor “j” and pumping power factor “f” decrease with increasing Reynolds number in a power of 0.805; while they are independent of chip heat flux. The Colburn analogy can be adequately employed in the study.

scholarly journals Engine Performance of a Gardener Compression Ignition Engine using Rapeseed Methyl Esther

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Hamisu A Dandajeh ◽  
Talib O Ahmadu
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Engine Speed ◽  
Engine Performance ◽  
Combustion Characteristics ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Air Mass

This paper presents an experimental investigation on the influence of engine speed on the combustion characteristics of a Gardener compression ignition engine fueled with rapeseed methyl esther (RME). The engine has a maximum power of 14.4 kW and maximum speed of 1500 rpm. The experiment was carried out at speeds of 750 and 1250 rpm under loads of 4, 8, 12, 16 and 18 kg. Variations of cylinder pressure with crank angle degrees and cylinder volume have been examined. It was found that RME demonstrated short ignition delay primarily due to its high cetane number and leaner fuel properties (equivalence ratio (φ) = 0.22 at 4kg). An increase in thermal efficiency but decrease in volumetric efficiency was recorded due to increased brake loads. Variations in fuel mass flow rate, air mass flow rate, exhaust gas temperatures and equivalence ratio with respect to brake mean effective pressure at engine speeds of 750 and 1250 rpm were also demonstrated in this paper. Higher engine speed of 1250 rpm resulted in higher fuel and air mass flow rates, exhaust temperature, brake power and equivalent ratio but lower volumetric efficiency. Keywords— combustion characteristics, engine performance, engine speed, rapeseed methyl Esther

scholarly journals The methodology for measuring the vibration amplitude of the blade of the aircraft engine compressor in the fatigue test

Mechanik ◽  
2018 ◽  
Vol 91 (3) ◽  
pp. 230-232
Author(s):  
Leszek Bielenda ◽  
Wojciech Obrocki ◽  
Maciej Masłyk ◽  
Jan Sieniawski
Keyword(s):  
Fatigue Test ◽  
Eddy Current ◽  
Vibration Amplitude ◽  
Aircraft Engine ◽  
Fatigue Tests ◽  
Compressor Blade ◽  
Additional Test ◽  
Blade Vibration ◽  
Comparison Research ◽  
Engine Compressor

Results of comparison research of various sensors types used in the fatigue tests for aircraft engine compressor blade vibration amplitude measurement were analysed. Sensors under tests: inductive, capacitive, eddy-current, laser and vibration. Presented were sensors characteristics and their faults. Additional test stand instrumentation was designed and performed, including mounting bracket.

scholarly journals Off-Design Performances of an Organic Rankine Cycle for Waste Heat Recovery from Gas Turbines

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1105 ◽  
Author(s):  
Carlo Carcasci ◽  
Lapo Cheli ◽  
Pietro Lubello ◽  
Lorenzo Winchler
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Air Temperature ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Ambient Air ◽  
Air Mass

This paper presents an off-design analysis of a gas turbine Organic Rankine Cycle (ORC) combined cycle. Combustion turbine performances are significantly affected by fluctuations in ambient conditions, leading to relevant variations in the exhaust gases’ mass flow rate and temperature. The effects of the variation of ambient air temperature have been considered in the simulation of the topper cycle and of the condenser in the bottomer one. Analyses have been performed for different working fluids (toluene, benzene and cyclopentane) and control systems have been introduced on critical parameters, such as oil temperature and air mass flow rate at the condenser fan. Results have highlighted similar power outputs for cycles based on benzene and toluene, while differences as high as 34% have been found for cyclopentane. The power output trend with ambient temperature has been found to be influenced by slope discontinuities in gas turbine exhaust mass flow rate and temperature and by the upper limit imposed on the air mass flow rate at the condenser as well, suggesting the importance of a correct sizing of the component in the design phase. Overall, benzene-based cycle power output has been found to vary between 4518 kW and 3346 kW in the ambient air temperature range considered.

Experimental Study of Spray Flame Characteristics in Hot-Diluted Oxidant Through Advanced Image Processing Technique

2017 ◽  
Author(s):  
Yuan Li ◽  
Hao Zhou ◽  
Ning Li ◽  
Kefa Cen
Keyword(s):  
Image Processing ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Air Mass ◽  
Fuel Flow ◽  
Spray Flame ◽  
Oxygen Concentrations

This paper presents a study of ethanol jet spray flame characteristics in a hot-diluted oxidant with different co-flow oxygen concentrations and fuel/air mass flow rate ratios (MF/MA ratios) through advance image processing technique. An air-blast atomizer was located in a McKenna burner which was utilized to provide stable combustion surroundings and variable combustion atmosphere for ethanol jet spray. The co-flow oxygen concentrations were set to 5%, 10%, 15% and 21% (by volume) by adjusting the mass flow rates of CH4, O2 and N2. The MF/MA ratios were set to 0.245, 0.490, 0.735, and 0.980 by adjusting the fuel mass flow rate and the carrier air mass flow rate. A high-speed RGB CCD camera was employed to capture spray flame images continuously. Spray flame edge is detected using an auto-adaptive edge-detection algorithm which could detect the spray flame edge continuously and clearly. A flame zone is defined as the region surrounded by the detected flame edge to obtain flame parameters. Spray flame characteristics are described using the measured flame parameters, involving flame area, length, brightness, nonuniformity and temperature which are derived from the spray flame images. Spray flame area, length, brightness and nonuniformity are extracted through image processing technique directly. Moreover, two-dimensional (2D) temperature profiling of spray flame is obtained by coupling image processing technique with two-color pyrometry based on Planck’s radiation law. The effects of co-flow oxygen concentration and MF/MA ratio on spray flame characteristics are investigated in this work. The spray flame parameters are observed to be sensitive to both co-flow oxygen concentration and MF/MA ratio. The results show that the fuel mass flow rate (MF) has opposite effects on spray flame characteristics compared with the carrier air mass flow rate (MA) in hot-diluted oxidant. Spray flame area and length are shown to decrease for higher co-flow oxygen concentrations, while spray flame brightness, uniformity and temperature are observed to increase for higher co-flow oxygen concentrations, owing to the enhancement of the combustion rate. A higher MF/MA ratio leads to higher spray flame area, length, brightness, uniformity and temperature, due to the increase of the droplet residence time or droplet concentration in hot-diluted oxidant. In the same MF/MA ratio, spray flame area and length are found to be smaller at a higher fuel flow rate (or carrier air flow rate). However, spray flame brightness, uniformity and temperature are demonstrated to be enhanced at a higher fuel flow rate (or carrier air flow rate). (CSPE)

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