Acoustic Measurements of Perforated Liners in Hot and Pressurized Flow

2013 ◽  
Author(s):  
Claus Lahiri ◽  
Karsten Knobloch ◽  
Friedrich Bake ◽  
Lars Enghardt
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Numerical Models ◽  
Experimental Tests ◽  
Acoustic Measurements ◽  
Test Rig ◽  
Acoustic Data ◽  
Bias Flow ◽  
Acoustic Instabilities ◽  
Acoustic Losses

Thermo-acoustic instabilities in gas turbine combustors can prevent the implementation of modern combustion concepts, which are essential for higher efficiency and lower emissions. Perforated combustor liners, especially in combination with a bias flow through the liner, are able to suppress the instabilities by increasing the acoustic losses of the system. Some insight into the parameter dependencies of the acoustic absorption has been gained by means of atmospheric testing at ambient temperature. The next step towards realistic testing conditions is taking into account high temperature and high pressure, which increases the effort of the experimental tests and the complexity of their analysis significantly. Tests in a real combustor can serve as a quality check of a given liner design, but are not appropriate for parameter studies. So far, numerical models accurate enough to enable the design of hot stream liners are simply not available, so that the experimental investigation of the liner’s dependency on temperature and pressure is essential for the transfer of laboratory scale results to a real engine application. A new test rig has been designed to overcome these problems. The Hot Acoustic Test rig (HAT) enables the study of the influence of pressure and temperature on the damping performance in an acoustically well defined environment, although the high temperature and high pressure conditions are challenging in terms of accurate acoustic measurements. This paper introduces the Hot Acoustic Test rig with its features and limitations and shows first examples of test results. The focus lies on the hardware, instrumentation, and analysis techniques that are necessary to obtain high quality acoustic data in hot and pressurized flow environments.

Analysis of Traction Characteristics of Grease-Lubricated Sliding Bearing

2013 ◽  
Vol 655-657 ◽  
pp. 640-643
Author(s):  
Bo Yuan Yang ◽  
Xiaofan Yan ◽  
Bing Su
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Room Temperature ◽  
Extreme Pressure ◽  
Test Rig ◽  
Sliding Bearing ◽  
Traction Coefficient ◽  
Lubrication Effect ◽  
Lubricated Sliding

Adopting the test rig of traction characteristics of grease-lubricated sliding bearing, the practical condition of sliding bearing was simulated and the traction coefficient of DGG Grease under different temperature, velocity and load was tested. Besides, the traction characteristics of the grease were also elaborated. The results indicate that the traction coefficient increases when the temperature gradually rises from room temperature while it gradually decreases when the temperature exceeds 85°C. Under the condition of high temperature and high pressure, the extreme pressure additive has obvious effects, the traction coefficient reducing and maintaining constant, so a better lubrication effect is realized.

An Innovative Design for Drillstring Testbed for High Pressure High Temperature Drilling

2020 ◽  
Author(s):  
Randall Tucker ◽  
Alan Palazzolo ◽  
Mohamed Gharib
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Simulation Software ◽  
Operating Conditions ◽  
Dynamics Simulation ◽  
Drilling Fluids ◽  
Test Rig ◽  
Stick Slip ◽  
Rock Interaction ◽  
High Pressure High Temperature

Abstract In this paper, a novel design for a full-scale, industrial-size, and high pressure high temperature (HPHT) drillstring test rig is presented. The test more accurately replicates the downhole environment with regards to bit performance limiters. The facility has a high-power drill string with side loading, reasonably sized mud pumps, a HPHT sample that generates a hot pressurized rock-bit interface and the ability to easily replicate specific drilling scenarios. This provides a step change in drilling research. Replicating down-hole HPHT conditions in a surface level drilling test rig is challenging but will deliver significant benefits for downhole tool and instrument development. The proposed test rig will provide these test conditions for developing longer lasting and more efficient bits, more effective drilling fluids, and lower friction tool joints to increase weight on bit (WOB) and rate of penetration (ROP). A secondary benefit is for identification of bit-rock interaction laws that will assist in implementing successful automated drilling (AD) approaches to reduce drillstring and bit failures from stick-slip, bit-bounce and other drilling anomalies. AD has the potential for increasing efficiency as well as reliability of drilling. The force and torque laws will also be utilized in drillstring dynamics simulation software for operator training and hardware development. The proposed test rig gives the industry a unique opportunity to couple experimental work that is representative of downhole conditions with actual industry problems and concerns. By using data sets from actual drilling operations, we will be able to replicate what is occurring downhole but in a controlled, measurable environment on the surface. The system will be highly automated with a remotely operated control room, to increase safety in the high temperature, pressure, force and torque environment of the test rig. The system is to be fully enclosed with an API rated pressure containment system. The description of the test rig here is intended to convey the complexity of the hardware needed to meet functionality requirements and operating conditions. The design is purposely configured to accommodate the inevitable small requirement modifications, with minimal delays in rig completion.

A Test Rig for Non-Contact Travelling Wave Excitation of a Bladed Disk With Underplatform Dampers

2010 ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
Muzio M. Gola
Keyword(s):  
Numerical Models ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Travelling Wave ◽  
Forced Response ◽  
Wave Excitation ◽  
Test Rig ◽  
Response Measurement ◽  
Static Test ◽  
Bladed Disk

The paper presents a static test rig called “Octopus” designed for the validation of numerical models aimed at calculating the nonlinear dynamic response of a bladed disk with underplatform dampers (UPDs). The test rig supports a bladed disk on a fixture and each UPD is pressed against the blade platforms by wires pulled by dead weights. Both excitation system and response measurement system are noncontacting. The paper features the design and the set-up of the noncontacting excitation generated by electromagnets placed under each blade. A travelling wave excitation is generated according to a desired engine order by shifting the phase of the harmonic force of one electromagnet with respect to the contiguous exciters. Since the friction phenomenon generated by UPDs introduces nonlinearities on the forced response, the amplitude of the exciting force must be kept constant at a known value on every blade during step-sine test to calculate Frequency Response Functions. The issue of the force control is therefore addressed since the performance of the electromagnet changes with frequency. The system calibration procedure and the estimated errors on the generated force are also presented. Examples of experimental tests that can be performed on a dummy integral bladed disk (blisk) mounted on the rig are described in the end.

FEM Simulation and Experimental Investigation of Reshaping of Thick Tubes in Different Passes

2009 ◽  
Author(s):  
A. Tajyar ◽  
K. Abrinia
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
High Temperature ◽  
Cold Rolling ◽  
Cross Section ◽  
Fem Simulation ◽  
Experimental Tests ◽  
Industrial Applications ◽  
Simulation Results ◽  
Roll Gap

Recent advances in high temperature and high pressure applications have made significant increase in industrial applications of square and rectangular seamless tubes. In this work, a reshaping process is presented with cold rolling of a circular thick tube into a square cross section between four flat rolls in different passes. The influence of the amount of roll gap reduction in each pass on the final rolled product was investigated. In order to verify the simulation results, several experimental tests were performed. Quantities such as separated force energy, wall thickness, and corner radius of the tube were observed and measured. Obtained results of simulation showed good agreements with the experiment results.

High Momentum Jet Flames at Elevated Pressure: Part D — Simultaneous Measurements of OH/PAH PLIF and Mie Scattering on Liquid Fuels

2019 ◽  
Author(s):  
Dominik Schäfer ◽  
James D. Gounder ◽  
Oliver Lammel ◽  
Holger Ax ◽  
Rainer Lückerath ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Mie Scattering ◽  
Liquid Fuels ◽  
High Momentum ◽  
Test Rig ◽  
Hot Gas ◽  
Liquid Phases

Abstract A promising alternative to modern swirl combustors for gas turbines are high momentum jet stabilized combustors. This gas turbine burner concept consists of circular arranged jet nozzles through which partially premixed high momentum jets enter the combustion chamber in axial direction. Furthermore, it features fuel flexibility, load flexibility and low pollutant emissions. The investigated generic combustor consists of an eccentric single nozzle in a square chamber. This nozzle represents a full-scale segment of a concentrically arranged multi-nozzle configuration. All measurements were carried out at the high pressure combustion test rig (HBK-S) at the German Aerospace Center (DLR) in Stuttgart. The generic single nozzle model combustor has been operated in a high-pressure test rig with large optical access in order to gain a detailed understanding of fuel distribution, droplet distribution, fuel air mixing and high temperature regions through various sections of the combustion chamber. For this purpose, different laser based measurement techniques have been applied simultaneously under gas turbine relevant conditions on liquid fuels (oil and oil/water). Other measurements in this combustor on gaseous fuels were presented in preceding (parts A and B) and current publications (part C). Mie scattering was used to visualize the liquid phase of oil and water downstream of the nozzle. In order to gain knowledge about the droplet velocity, a Nd:YAG double pulse laser at 532 nm was used for Particle Image Velocimetry (PIV). Additionally the gaseous and liquid phases of oil have been visualized through Planar Laser Induced Fluorescence (PLIF) by excitation of poly-cyclic aromatic hydrocarbons (PAHs) with a laser wavelength of 266 nm. To observe high temperature regions, OH and PAH PLIF was also performed with a low bandwidth at 283 nm from a Nd:YAG pumped dye laser. It was possible to separate the low-intensity OH signal of the hot gas regions from the PAH signal by collecting the different LIF signals simultaneously through a dual camera setup. Instantaneous PAH LIF images of the liquid and gaseous phase were compared with Mie scattering images for a qualitative impression of the evaporation. For this a structural comparison between the liquid phases of both images has been carried out. Results indicate, that the evaporation of most of the liquid fuel takes place near the hot gas region, as a large proportion of droplets are carried far downstream of the nozzle by the high momentum jet.

scholarly journals Detection of vaneless diffuser rotating stall by means of dynamic pressure sensors and acoustic measurements

2021 ◽  
Vol 312 ◽  
pp. 11007
Author(s):  
Luca Romani ◽  
Lorenzo Bosi ◽  
Alberto Baroni ◽  
Lorenzo Toni ◽  
Davide Biliotti ◽  
...  
Keyword(s):  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Experimental Tests ◽  
Rotating Stall ◽  
Accurate Estimation ◽  
Sufficient Information ◽  
Acoustic Measurements ◽  
Vaneless Diffuser ◽  
Test Rig ◽  
Ensemble Averaging

An accurate estimation of rotating stall is one of the key technologies for high-pressure centrifugal compressors. Several techniques have been proposed to detect the stall onset; inter alia, few dynamic pressure probes have been shown to not only properly detect the phenomenon, but also reconstruct the stall characteristics after an ensemble averaging approach. The massive use of this technique in the field is, however, not a common practice yet. In the present study, the use of dynamic pressure probes has been combined with that of an environmental microphone to evaluate the prospects of this latter for a possible stall onset detection. To this end, experimental tests have been carried out in the experimental test rig of the Department of Industrial Engineering (DIEF) of Università degli Studi di Firenze. Results show that the microphone was able to distinguish the onset of rotating stall accurately and promptly, even though – differently from dynamic pressure sensors - it does not provide sufficient information to determine the characteristics of the stall pattern. On this basis, the use of acoustic measurements could find room for automatic detection of rotating stall onset.

A Test Rig for Noncontact Traveling Wave Excitation of a Bladed Disk With Underplatform Dampers

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
Muzio M. Gola
Keyword(s):  
Traveling Wave ◽  
Numerical Models ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Forced Response ◽  
Wave Excitation ◽  
Test Rig ◽  
Response Measurement ◽  
Static Test ◽  
Bladed Disk

This paper presents a static test rig called “Octopus” designed for the validation of numerical models aimed at calculating the nonlinear dynamic response of a bladed disk with underplatform dampers (UPDs). The test rig supports a bladed disk on a fixture and each UPD is pressed against the blade platforms by wires pulled by dead weights. Both excitation system and response measurement system are noncontacting. This paper features the design and the setup of the noncontacting excitation generated by electromagnets placed under each blade. A traveling wave excitation is generated according to a desired engine order by shifting the phase of the harmonic force of one electromagnet with respect to the contiguous exciters. Since the friction phenomenon generated by UPDs introduces nonlinearities on the forced response, the amplitude of the exciting force must be kept constant at a known value on every blade during step-sine test to calculate frequency response functions. The issue of the force control is therefore addressed since the performance of the electromagnet changes with frequency. The system calibration procedure and the estimated errors on the generated force are also presented. Examples of experimental tests that can be performed on a dummy integral bladed disk (blisk) mounted on the rig are described in the end.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

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