Experimental Studies on the Thermoacoustics of Afterburner Screech Combustion Instabilities in a Model Afterburner Test Rig

2020 ◽  
pp. 187-201
Author(s):  
C. Rajashekar ◽  
Shambhoo ◽  
H. S. Raghukumar ◽  
G. Sriram ◽  
S. Chenthil Kumar ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Combustion Instabilities ◽  
Test Rig

scholarly journals Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

2007 ◽  
Vol 7 (5) ◽  
pp. 15105-15154 ◽  
Author(s):  
A. Petzold ◽  
J. Hasselbach ◽  
P. Lauer ◽  
R. Baumann ◽  
K. Franke ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Number ◽  
Marine Boundary Layer ◽  
Experimental Studies ◽  
Test Bed ◽  
Test Rig ◽  
Particle Emissions ◽  
Airborne Measurements ◽  
Emission Studies ◽  
Transformation Processes

Abstract. Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B{&amp;}W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transformation studies in the plume of a large container ship in the English Channel using the DLR aircraft Falcon 20 E-5. Observations from emission studies and plume studies combined with a Gaussian plume dispersion model yield a consistent picture of particle transformation processes from emission to atmospheric processing during plume expansion. Particulate matter emission indices obtained from plume measurements are 8.8±1.0×1015(kg fuel)−1 by number for non-volatile particles and 174±43 mg (kg fuel)−1 by mass for Black Carbon (BC). Values determined for test rig conditions between 85 and 110% engine load are of similar magnitude. For the total particle number including volatile compounds no emission index can be derived since the volatile aerosol fraction is subject to rapid transformation processes in the plume. Ship exhaust particles occur in the size range Dp<0.3 μm, showing a bi-modal structure. The combustion particle mode is centred at modal diameters of 0.05 μm for raw emissions to 0.10 μm at a plume age of 1 h. The smaller-sized volatile particle mode is centred at Dp≤0.02 μm. From the decay of ship exhaust particle number concentrations in an expanding plume, a maximum plume life time of approx. 24 h is estimated for a well-mixed marine boundary layer.

Modelling of Thermoacoustic Combustion Instabilities Phenomena: Application to an Experimental Rig for Testing Full Scale Burners

2014 ◽  
Author(s):  
Davide Laera ◽  
Giovanni Campa ◽  
Sergio M. Camporeale ◽  
Edoardo Bertolotto ◽  
Sergio Rizzo ◽  
...  
Keyword(s):  
Acoustic Analysis ◽  
Fem Analysis ◽  
Full Scale ◽  
Operating Conditions ◽  
System Modelling ◽  
Combustion Instabilities ◽  
Test Rig ◽  
Pressure Oscillations ◽  
Secondary Air ◽  
Actual Geometry

This paper concerns the acoustic analysis of self–sustained thermoacoustic pressure oscillations that occur in a test rig equipped with full scale lean premixed burner. The experimental work is conducted by Ansaldo Energia and CCA (Centro Combustione Ambiente) at the Ansaldo Caldaie facility in Gioia del Colle (Italy), in cooperation with Politecnico di Bari. The test rig is characterized by a longitudinal development with two acoustic volumes, plenum and combustion chamber, coupled by the burner. The length of both chambers can be varied with continuity in order to obtain instability at different frequencies. A previously developed three dimensional finite element code has been applied to carry out the linear stability analysis of the system, modelling the thermoacoustic combustion instabilities through the Helmholtz equation under the hypothesis of low Mach approximation. The heat release fluctuations are modelled according to the κ-τ approach. The burner, characterized by two conduits for primary and secondary air, is simulated by means of both a FEM analysis and a Burner Transfer Matrix (BTM) method in order to examine the influence of details of its actual geometry. Different operating conditions, in which self–sustained pressure oscillations have been observed, are examined. Frequencies and growth rates of unstable modes are identified, with good agreement with experimental data in terms of frequencies and acoustics pressure wave profiles.

scholarly journals Microturbine-Based Test Rig for Emulation of SOFC Hybrid Systems

2019 ◽  
Vol 113 ◽  
pp. 02004 ◽  
Author(s):  
Mario L. Ferrari ◽  
Matteo Pascenti ◽  
Aristide F. Massardo
Keyword(s):  
Fuel Cell ◽  
Risk Analysis ◽  
Electric Power ◽  
Hybrid Systems ◽  
Experimental Studies ◽  
Component Analysis ◽  
Test Rig ◽  
Dynamic Conditions

This work is devoted to an emulator test rig based on a T100 microturbine (100 kW electric power) and designed for SOFC hybrid systems. Since this facility does not include a real fuel cell, it is mainly used for tests on the SOFC/T100 integration to analyse possible stress and risky operations (e.g. surge) especially in dynamic conditions. The tests performed with this rig range from component analysis, to experimental studies at dynamic conditions and surge risk analysis.

EXPERIMENTAL STUDIES ON THE INFLUENCE OF ABRASIVE MATERIALS ON THE WEAR OF HARD-WEARING STEELS

Tribologia ◽  
2018 ◽  
Vol 281 (5) ◽  
pp. 133-141 ◽  
Author(s):  
Andrzej N. WIECZOREK
Keyword(s):  
Experimental Studies ◽  
Structural Steels ◽  
Operating Conditions ◽  
Ring Test ◽  
Test Rig ◽  
Wear Properties ◽  
Aggressive Action ◽  
Low Wear ◽  
Loss Of Mass ◽  
Wear Tests

The paper presents the wear properties of hard-wearing steels and structural steels used in mining and transport machines exposed to the aggressive action of the environment, which have been determined experimentally in the presence of diverse abrasive materials. The wear tests were carried out on a ring-on-ring test rig simulating the operating conditions of elements exposed to abrasive wear. The samples were subjected to tests in conditions of sliding contact, and the main destructive process was micro-cutting of the surface with loose corundum or quartz grain. In the case of the coal abrasive, only slight grinding in of the mating surfaces was observed. The loss of mass in the samples was measured as the parameter characterizing the wear. It was then used to determine the volume loss. Based on the results obtained, it was found that the wear resistance of hard-wearing steels was approximately four times higher as compared to S355J2 structural steel for the corundum and quartz abrasives. In the case of the coal abrasive, there was a relatively low wear for all of the materials examined.

The Experimental Studies of Improving the Aerodynamic Performance of a Turbine Exhaust System

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Stephen Guillot ◽  
Wing F. Ng ◽  
Hans D. Hamm ◽  
Ulrich E. Stang ◽  
Kevin T. Lowe
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Experimental Studies ◽  
Experimental Result ◽  
Test Facility ◽  
Test Rig ◽  
Blow Down ◽  
Recovery Coefficient ◽  
Scale Test ◽  
Turbine Exhaust

Analysis and testing were conducted to optimize an axial diffuser–collector gas turbine exhaust. Two subsonic wind tunnel facilities were designed and built to support this program. A 1/12th scale test rig enabled rapid and efficient evaluation of multiple geometries. This test facility was designed to run continuously at an inlet Mach number of 0.41 and an inlet hydraulic diameter-based Reynolds number of 3.4 × 105. A 1/4th geometric scale test rig was designed and built to validate the data in the 1/12th scale rig. This blow-down rig facilitated testing at a nominally equivalent inlet Mach number, while the Reynolds number was matched to realistic engine conditions via back pressure. Multihole pneumatic pressure probes, particle image velocimetry (PIV), and surface oil flow visualization were deployed in conjunction with computational tools to explore physics-based alterations to the exhaust geometry. The design modifications resulted in a substantial increase in the overall pressure recovery coefficient of +0.07 (experimental result) above the baseline geometry. The optimized performance, first measured at 1/12th scale and obtained using computational fluid dynamics (CFD) was validated at the full scale Reynolds number.

Experimentally-Tuned Mathematical Model for Drillstring Vibrations

2007 ◽  
Author(s):  
Y. A. Khulief ◽  
F. A. Al-Sulaiman
Keyword(s):  
Dynamic Models ◽  
Drilling Fluid ◽  
Experimental Studies ◽  
Published Data ◽  
Test Rig ◽  
Stick Slip ◽  
Multibody Model ◽  
Drilling Performance ◽  
Weight On Bit ◽  
Functional Operation

Field experience manifests that drillstring vibration is one of the major causes for a deteriorated drilling performance. It is crucial to understand the complex vibrational mechanisms experienced by a drilling system in order to better control its functional operation and improve its performance. Experimental studies of drillstring dynamics are essential to complement the theoretical studies, and to alleviate the complexity of such dynamic models. This paper presents an experimental investigation using a specially designed drilling test rig. The test rig can simulate the drillstring vibrational response due to various excitation mechanisms, which include stick-slip, well-borehole contact, and drilling fluid interaction. The test rig is driven by a variable speed motor which allows for testing different drilling speeds, while a magnetic tension brake is used to simulated stick-slip. In addition, a shaker is employed to excite the drillstring axially in order to simulate the weight-on-bit (WOB). The drillstring is instrumented for vibration measurements. The experimentally identified parameters are used to refine the finite element multibody model of the drillstring, which was derived earlier by the investigators [1]. Comparisons with published data demonstrate the reliability of the developed scheme for prediction of drillstring vibrations.

Analysis of Lift off Height and Blow-Off Mechanism of Turbulent Flame by V-Gutter Bluff Body

2015 ◽  
Vol 787 ◽  
pp. 727-731 ◽  
Author(s):  
S. Boopathi ◽  
P. Maran ◽  
V. Caleb Eugene ◽  
S. Prabhu
Keyword(s):  
Bluff Body ◽  
Recirculation Zone ◽  
Turbulent Flame ◽  
Flame Stability ◽  
Bluff Bodies ◽  
Combustion Instabilities ◽  
Test Rig ◽  
Square Duct ◽  
Flame Holder ◽  
Lift Off

The experimental investigation has been carried out to study the stabilization and blowout mechanisms of turbulent flame stabilized by V-gutter bluff body in a square duct at reactive and non-reactive conditions. V-shaped bluff bodies made of stainless steel having 1.6 mm thicknessare used for stabilization of the flame.Experiments have been conducted at selective velocities of commercially available methane and oxygen with 60 degree V-gutter as flame holder. It is observed that at stoichiometric conditions, the V-gutter is dominated by shear layer stabilized flames. The flame stability is influenced by bluff body dimensions and mass flow rate which play a major role in combustion instabilities mixing of air fuel ratio and blow off. The lift off decreases at higher blockage ratios.A strong recirculation zone is found in this test rig immediately downstream of the V-Gutter which gradually subsides and disappears far downstream.The lift off height is not much affected by the velocity of the fuel-air mixture.

Experimental research on suppressing unbalanced vibration of rotor by integral squeeze film damper

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Yan ◽  
Lidong He ◽  
Zhe Deng ◽  
Xingyun Jia
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Structural Characteristics ◽  
Experimental Studies ◽  
Rotor System ◽  
Squeeze Film ◽  
Rigid Rotor ◽  
Flexible Rotor ◽  
Test Rig ◽  
Squeeze Film Damper

Abstract As a novel structural damper, the unique structural characteristics of the integral squeeze film damper (ISFD) solve the nonlinear problem of the traditional squeeze film damper (SFD), and it has good linear damping characteristics. In this research, the experimental studies of ISFD vibration reduction performance are carried out for various working conditions of unbalanced rotors. Two ball bearing-rotor system test rigs are built based on ISFD: a rigid rotor test rig and a flexible rotor test rig. When the rotational speed of rigid rotor is 1500 rpm, ISFD can reduce the amplitude of the rotor by 41.79%. Under different unbalance conditions, ISFD can effectively improve the different degrees of unbalanced faults in the rotor system, reduce the amplitude by 43.21%, and reduce the sensitivity of the rotor to unbalance. Under different rotational speed conditions, ISFD can effectively suppress the unbalanced vibration of rigid rotor, and the amplitude can be reduced by 53.51%. In the experiment of the unbalanced response of the flexible rotor, it is found that ISFD can improve the damping of the rotor system, effectively suppress the resonance of the rotor at the critical speed, and the amplitude at the first-order critical speed can be reduced by 31.72%.

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