Experimental investigations on effects of axial clearance on high-speed turbine expansion generator rotor response

We have developed a novel surgical/computational model for the investigation of unilat-eral vocal fold paralysis (UVFP) which will be used to inform future in silico approaches to improve surgical outcomes in type I thyroplasty. Healthy phonation (HP) was achieved using cricothyroid suture approximation on both sides of the larynx to generate symmetrical vocal fold closure. Following high-speed videoendoscopy (HSV) capture, sutures on the right side of the larynx were removed, partially releasing tension unilaterally and generating asymmetric vocal fold closure characteristic of UVFP (sUVFP condition). HSV revealed symmetric vibration in HP, while in sUVFP the sutured side demonstrated a higher frequency (10–11%). For the computational model, ex vivo magnetic resonance imaging (MRI) scans were captured at three configurations: non-approximated (NA), HP, and sUVFP. A finite-element method (FEM) model was built, in which cartilage displacements from the MRI images were used to prescribe the adduction, and the vocal fold deformation was simulated before the eigenmode calculation. The results showed that the frequency comparison between the two sides was consistent with observations from HSV. This alignment between the surgical and computational models supports the future application of these methods for the investigation of treatment for UVFP.

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14. Theoretical and experimental investigations on a new high speed CVD method for carbon and other substances

Carbon ◽

10.1016/0008-6223(69)90543-0 ◽

1969 ◽

Vol 7 (6) ◽

pp. 711

Author(s):

H Lydtin

Keyword(s):

High Speed ◽

Experimental Investigations ◽

Cvd Method ◽

Other Substances

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Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4049662 ◽

2021 ◽

Author(s):

Jingjing Luo ◽

Dieter Brillert

Keyword(s):

High Speed ◽

Gas Flow ◽

Static Pressure ◽

Pressure Sensors ◽

Operating Conditions ◽

Test Facility ◽

Experimental Investigations ◽

Mechanical Seals ◽

Process Gas ◽

Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

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Prechamber optimal selection for a two stage turbulent jet ignition type combustion system in CNG-fuelled engine

Combustion Engines ◽

10.19206/ce-2019-103 ◽

2019 ◽

Vol 176 (1) ◽

pp. 16-26 ◽

Cited By ~ 1

Author(s):

Ireneusz PIELECHA ◽

Wojciech BUESCHKE ◽

Maciej SKOWRON ◽

Łukasz FIEDKIEWICZ ◽

Filip SZWAJCA ◽

...

Keyword(s):

High Speed ◽

Internal Combustion Engines ◽

Combustion Process ◽

Optimization Methods ◽

Turbulent Jet ◽

Experimental Investigations ◽

Combustion System ◽

Two Stage ◽

Lean Burn ◽

High Speed Engine

Searching for further reduction of fuel consumption simultaneously with the reduction of toxic compounds emission new systems for lean-mixture combustion for SI engines are being discussed by many manufacturers. Within the European GasOn-Project (Gas Only Internal Combustion Engines) the two-stage combustion and Turbulent Jet Ignition concept for CNG-fuelled high speed engine has been proposed and thoroughly investigated where the reduction of gas consumption and increasing of engine efficiency together with the reduction of emission, especially CO2 was expected. In the investigated cases the lean-burn combustion process was conducted with selection of the most effective pre-combustion chamber. The experimental investigations have been performed on single-cylinder AVL5804 research engine, which has been modified to SI and CNG fuelling. For the analysis of the thermodynamic, operational and emission indexes very advanced equipment has been applied. Based on the measuring results achieved for different pre-chamber config-urations the extended methodology of polioptimization by pre-chamber selection and the shape of main chamber in the piston crown for proposed combustion system has been described and discussed. The results of the three versions of the optimization methods have been comparatively summarized in conclusions.

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MEASURING DISPLACEMENT AND VELOCITY OF A STRIKER USING A RADIO-INTERFEROMETER

Problems of Strength and Plasticity ◽

10.32326/1814-9146-2019-81-1-118-128 ◽

2019 ◽

Vol 81 (1) ◽

pp. 118-128

Author(s):

V. V. Balandin ◽

V. V. Parkhachev

Keyword(s):

High Speed ◽

Radio Interferometer ◽

Experimental Investigations ◽

X Ray ◽

Gas Gun ◽

Impact Interaction ◽

Ballistic Experiment ◽

Wide Range ◽

Series Of Experiments ◽

Error Of Measurement

Investigating impact interaction of solid and deformed bodies with obstacles of various physical natures requires developing experimental methodologies of registering the parameters of the interaction process. In experimental investigations of impact interaction of solids, it is common practice to measure displacement of strikers as a function of time, as well as their velocity and deceleration. To determine the displacement and velocity of a striker, a radio-interferometric methodology of registering the displacement of its rear end is proposed. In contrast with the registration methods based on high-speed filming and pulsed X-ray photography, the method using a millimeter-range radio-interferometer provides continuous high-accuracy registering of the displacement of the rear end of a striker in a wide range of displacement values. To test the effectiveness of the methodology, a series of experiments have been conducted on registering the motion of a cylindrical striker of an aluminum alloy, fired from a 20mm-dia gas gun. The displacement of the striker was also monitored using high-speed filming. The results of measuring using the two methodologies differ within the limits of the error of measurement. Based on the results of the above experiments, it has been concluded that the methodology of determining the displacement and velocity of strikers in a ballistic experiment using a mm-range radio-interferometer makes it possible to measure practically continuously large displacements (100 mm and larger) to a safe accuracy. The present methodology can be used for measuring the displacement and velocity of the rear end of a striker interacting with obstacles of various physical natures (metals, ceramics, soils, concretes, etc.).

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Experimental Study of Water Flow in Full-Size Test Rig for Water-Cooled Turbo-Generator Rotor

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1966_181_011_02 ◽

1966 ◽

Vol 181 (1) ◽

pp. 53-73 ◽

Cited By ~ 6

Author(s):

I. K. Csillag

Keyword(s):

Operating Conditions ◽

Experimental Investigations ◽

Air Cooling ◽

Test Rig ◽

Full Size ◽

Generator Rotor ◽

Turbo Generator ◽

Hydrogen Cooling ◽

Major Factors ◽

Design And Manufacture

The demand for electric power has doubled in the last decade. The most economical way to meet this demand is by building large-output generating units. The study of the major factors which determine the output of such generators shows that the only effective way to increase the output is by improving the cooling of their windings. For that reason design has progressed from air-cooling to indirect hydrogen-cooling, then to direct hydrogen-cooling. Now the trend is towards direct water-cooling where the water is in direct contact with the copper windings. The introduction of water into the stator winding was established in 1956 (1)† and was in fact directly responsible for the present increase in unit rating. The introduction of water to a rotating winding presents difficult problems in both design and manufacture. The test rig dealt with in this paper was built to study some of these problems and to carry out experimental investigations on a full size model of the special hydraulic features for a water-cooled turbo-generator rotor. The investigations were concentrated around the following five different problems which are dealt with in detail: (1) increase in pressure drop due to rotation; (2) free-rotating seal (inlet seal) (2); (3) vacuum-breaking device (water outlet) (3); (4) loss-distribution in the rotor; (5) measurement of the rotor vibrations in various operating conditions.

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The Effects of Inlet Boundary Layer Condition and Periodically Incoming Wakes on Secondary Flow in a Low Pressure Turbine Cascade

Volume 2B: Turbomachinery ◽

10.1115/gt2020-14242 ◽

2020 ◽

Author(s):

Tobias Schubert ◽

Silvio Chemnitz ◽

Reinhard Niehuis

Keyword(s):

Boundary Layer ◽

Secondary Flow ◽

High Speed ◽

Low Pressure ◽

Experimental Investigations ◽

Turbine Cascade ◽

Flow Conditions ◽

Low Pressure Turbine ◽

Speed Flow ◽

Unsteady Inflow

Abstract A particular turbine cascade design is presented with the goal of providing a basis for high quality investigations of endwall flow at high-speed flow conditions and unsteady inflow. The key feature of the design is an integrated two-part flat plate serving as a cascade endwall at part-span, which enables a variation of the inlet endwall boundary layer conditions. The new design is applied to the T106A low pressure turbine cascade for endwall flow investigations in the High-Speed Cascade Wind Tunnel of the Institute of Jet Propulsion at the Bundeswehr University Munich. Measurements are conducted at realistic flow conditions (M2th = 0.59, Re2th = 2·105) in three cases of different endwall boundary layer conditions with and without periodically incoming wakes. The endwall boundary layer is characterized by 1D-CTA measurements upstream of the blade passage. Secondary flow is evaluated by Five-hole-probe measurements in the turbine exit flow. A strong similarity is found between the time-averaged effects of unsteady inflow conditions and the effects of changing inlet endwall boundary layer conditions regarding the attenuation of secondary flow. Furthermore, the experimental investigations show, that all design goals for the improved T106A cascade are met.

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Experimental Investigation of the Effect of the Machine Kinematic Behavior on the Surface Topography and Roughness in High Speed Ball end Milling of the AISI4142 Steel

10.21203/rs.3.rs-197062/v1 ◽

2021 ◽

Author(s):

Sai Lotfi ◽

Belguith Rami ◽

Baili Maher ◽

Desseins Gilles ◽

Bouzid Wassila

Keyword(s):

Surface Topography ◽

High Speed ◽

End Milling ◽

Experimental Investigations ◽

Ball End Milling ◽

Tool Paths ◽

Stationary Zone ◽

Machining Errors ◽

Kinematic Behavior ◽

Milling Tool

Abstract The analysis of the surface topography in ball end milling is an objective studied by many researchers, several methods were used and many combinations of cutting conditions and machining errors are considered. In the milling tool paths the trajectories presents a points of changing direction where the tool decelerates before and accelerates after respecting the velocity profiles of the machine. In this paper, we propose experimental investigations of the effect of the kinematic behavior of the machine tool on the surface quality. A poor topography and roughness are remarked on the deceleration and the acceleration zones compared to the stationary zone.

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Investigations Of Pressure Pulsations In A Model Of Draft Tube Of Hydraulic Turbine Caused By Vortex Rings

Siberian Journal of Physics ◽

10.54362/1818-7919-2016-11-4-25-32 ◽

2016 ◽

Vol 11 (4) ◽

pp. 25-32

Author(s):

Sergey Skripkin ◽

Mikhail Tsoy ◽

Sergey Shtork ◽

Pavel Kuibin

Keyword(s):

Vortex Ring ◽

High Speed ◽

Draft Tube ◽

Hydraulic Turbine ◽

Vortex Rings ◽

Experimental Investigations ◽

Visualization Technique ◽

Vortex Rope ◽

Hydro Turbine ◽

Hydraulic Turbines

Current work is devoted to experimental investigations of behavior of precessing vortex rope in a draft tube model of hydraulic turbine. We used combination of stationary and freely rotating swirlers as a hydro turbine model. Such construction provides velocity distribution on the draft tube inlet close to distribution in natural hydraulic turbines operated at non-optimal conditions. The phenomenon of precessing vortex rope reconnection with further formation of vortex ring was founded in this experimental research using high-speed visualization technique. Synchronization of highspeed visualization and pressure measurements allowed us to relate pressure shock on the draft tube wall with vortex ring moving along wall.

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Numerical and Experimental Investigations on Reducing Particle Accumulation for SCR-deNOx Facilities

Applied Sciences ◽

10.3390/app9194158 ◽

2019 ◽

Vol 9 (19) ◽

pp. 4158

Author(s):

Zeng ◽

Yuan ◽

Wang

Keyword(s):

High Speed ◽

Power Plants ◽

Catalyst Deactivation ◽

Catalytic Reduction ◽

Experimental Investigations ◽

Duct Flow ◽

Cfd Simulations ◽

Particle Accumulation ◽

Computational Fluid Dynamics Cfd ◽

Vertical Duct

Selective catalytic reduction (SCR) is widely used to remove nitrogen oxides (NOx) in the flue gas of coal-fired power plants. The accumulation of ash particles inside the SCR-deNOx facility will increase the risk of catalyst deactivation or even damage. This paper presents the numerical and experimental investigations on the particle dispersal approach for the SCR-deNOx facility of a 1000 MW coal-fired power plant. The accumulation of different-sized particles is evaluated based on computational fluid dynamics (CFD) simulations. To prevent particles from accumulation, an optimized triangular deflector is proposed and attempts are made to find out the optimal installing position of the deflector. For the π-type SCR-deNOx facilities, the particle accumulation predominantly occurred on one side of the catalysts’ entrance, which corresponds to the inner side of the wedge-shaped turning. It is indicated that particles larger than 8.8 × 10−2 mm are responsible for the significant accumulation. The triangular deflector is proved to be an effective way to reduce particle accumulation and is found most efficient when it is installed at the high-speed area of the vertical duct. Flow model test (FMT) is carried out to validate the dispersal effect for the particle with relatively large sizes and the optimal installing position of the triangular deflector.

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