Experimental Analysis Methods for Unsteady Flows in Turbomachines

1981 ◽  
Vol 103 (2) ◽  
pp. 415-423 ◽  
Author(s):  
R. Larguier
Keyword(s):  
Experimental Analysis ◽  
Time Pressure ◽  
Unsteady Flows ◽  
Rotor Blades ◽  
Hot Wire ◽  
Short Response Time ◽  
Pressure Transducers ◽  
Direct Measurements ◽  
Hot Film

This paper describes the measuring methods developed at the ONERA Aerodynamics Department for the characterization of unsteady flows in turbomachines. They mainly concern the flow in the rotor, its wake, and boundary layers on stator or rotor blades. The means used consist of: • measurements using pressure probes or short response time pressure transducers, • measurements with hot wire probes or hot film gauges, and • direct, measurements using laser velocimeter.

Characterization of Local Cavity Pressures in Squeeze Casting of Magnesium Alloy AM50

2014 ◽  
Vol 936 ◽  
pp. 1666-1670
Author(s):  
Xue Zhi Zhang ◽  
Alfred Yu ◽  
Henry Hu
Keyword(s):  
Magnesium Alloy ◽  
Pressure Distribution ◽  
Experimental Measurement ◽  
Transfer Rate ◽  
Squeeze Casting ◽  
Time Pressure ◽  
Pressure Measurements ◽  
Pressure Transducers ◽  
Alloy Am50

In this study, the experimental measurement of the pressure distribution in a cylindrical die cavity for squeeze casting of magnesium alloy AM50A was carried out. Piezo-electric quartz pressure transducers were integrated into a die cavity for real-time pressure measurements. The experimental results revealed that local cavity pressures at various locations changed with time in the duration of squeeze casting solidification and cooling. The pressure transfer rate varied considerably within the casting geometry. The distribution of local cavity pressures was inhomogeneous in the cavity.

scholarly journals Multi-Camera Based Setup for Geometrical Measurement of Free-Falling Molten Glass Gob

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1041
Author(s):  
Mazhar Hussain ◽  
Mattias O’Nils ◽  
Jan Lundgren
Keyword(s):  
Free Fall ◽  
Frame Rate ◽  
Geometrical Parameters ◽  
Contactless Method ◽  
Molten Material ◽  
Dynamic Changes ◽  
Direct Measurements ◽  
Molten Materials ◽  
Free Falling

High temperatures complicate the direct measurements needed for continuous characterization of the properties of molten materials such as glass. However, the assumption that geometrical changes when the molten material is in free-fall can be correlated with material characteristics such as viscosity opens the door to a highly accurate contactless method characterizing small dynamic changes. This paper proposes multi-camera setup to achieve accuracy close to the segmentation error associated with the resolution of the images. The experimental setup presented shows that the geometrical parameters can be characterized dynamically through the whole free-fall process at a frame rate of 600 frames per second. The results achieved show the proposed multi-camera setup is suitable for estimating the length of free-falling molten objects.

Combined Simultaneous Flow Visualization/Hot-Wire Anemometry for the Study of Turbulent Flows

1980 ◽  
Vol 102 (2) ◽  
pp. 174-182 ◽  
Author(s):  
R. E. Falco
Keyword(s):  
Pressure Gradient ◽  
Flow Visualization ◽  
Turbulent Flows ◽  
Unsteady Flows ◽  
Gradient Flows ◽  
Hot Wire ◽  
Visual Patterns ◽  
Favorable Pressure Gradient ◽  
Hot Wire Anemometry ◽  
Scattering Light

The measurement of coherent motions in turbulent and unsteady flows is discussed. A technique which discriminates these motions based upon the patterns they create by scattering light from a fog of tiny oil drops is described. It is shown that hot-wire anemometry can be used in this oil fog so that hot-wire data can be conditionally sampled to the visual patterns, giving directly interpretable measures of the importance of the selected features. The three-dimensionality of the coherent motions can also be directly accounted for, using mutually orthogonal sheets of light. Results of step flows, and zero and favorable pressure gradient flows are described.

The Role of Fluid Flow Phenomena in the Czochralski Growth of Oxides.

1981 ◽  
Vol 9 ◽  
Author(s):  
D.C. Miller
Keyword(s):  
Fluid Flow ◽  
Defect Density ◽  
Major Effect ◽  
Czochralski Growth ◽  
Simulation Experiments ◽  
Direct Measurements ◽  
Flow Geometry ◽  
Flow Phenomena

ABSTRACTIn the Czochralski growth of single crystals from large melts, fluid flow phenomena have a major effect on interface shape, growth striations, defect density and the length of crystals which can be grown from a melt of given volume and thermal geometry. Because of the technical difficulties encountered in making direct measurements in molten oxides, simulation experiments have been extensively utilized to gain insight into melt behavior.Both temperature profile and flow geometry results from simulation experiments are discussed. This data is supported by direct melt observations and results from the characterization of grown crystals. When reviewed together, this information offers new insights into the complex behavior of Czochralski growth processes, including the role of thermal gradients, crystal rotation, and surface tension driven (Marangoni) convection.

scholarly journals Simultaneous profiling of multiple chromatin proteins in the same cells

2021 ◽  
Author(s):  
Sneha Gopalan ◽  
Yuqing Wang ◽  
Nicholas W. Harper ◽  
Manuel Garber ◽  
Thomas G Fazzio
Keyword(s):  
Rna Polymerase Ii ◽  
Direct Analysis ◽  
Cell Types ◽  
Regulatory Elements ◽  
Genome Wide ◽  
Distinct Cell ◽  
Direct Measurements ◽  
Cell Type Specific ◽  
Chromatin Proteins

Methods derived from CUT&RUN and CUT&Tag enable genome-wide mapping of the localization of proteins on chromatin from as few as one cell. These and other mapping approaches focus on one protein at a time, preventing direct measurements of co-localization of different chromatin proteins in the same cells and requiring prioritization of targets where samples are limiting. Here we describe multi-CUT&Tag, an adaptation of CUT&Tag that overcomes these hurdles by using antibody-specific barcodes to simultaneously map multiple proteins in the same cells. Highly specific multi-CUT&Tag maps of histone marks and RNA Polymerase II uncovered sites of co-localization in the same cells, active and repressed genes, and candidate cis-regulatory elements. Single-cell multi-CUT&Tag profiling facilitated identification of distinct cell types from a mixed population and characterization of cell type-specific chromatin architecture. In sum, multi-CUT&Tag increases the information content per cell of epigenomic maps, facilitating direct analysis of the interplay of different proteins on chromatin.

scholarly journals The Development of Fast Response Aerodynamic Probes for Flow Measurements in Turbomachinery

1994 ◽  
Author(s):  
Roger W. Ainsworth ◽  
John L. Allen ◽  
J. Julian M. Batt
Keyword(s):  
Mach Number ◽  
Large Scale ◽  
Flow Direction ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
Fast Response ◽  
Rotor Blades ◽  
Small Scale ◽  
Hot Wire ◽  
Flow Measurements

The advent of a new generation of transient rotating turbine simulation facilities, where engine values of Reynolds and Mach number are matched simultaneously together with the relevant rotational parameters for dimensional similitude (Dunn et al [1988], Epstein et al [1984]. Ainsworth et al [1988]), has provided the stimulus for developing improved instrumentation for investigating the aerodynamic flows in these stages. Much useful work has been conducted in the past using hot-wire and laser anemometers. However, hot-wire anemometers are prone to breakage in the high pressure flows required for correct Reynolds numbers, Furthermore some laser techniques require a longer runtime than these transient facilites permit, and generally yield velocity information only, giving no data on loss production. Advances in semiconductor aerodynamic probes are beginning to fulfil this perceived need. This paper describes advances made in the design, construction, and testing of two and three dimensional fast response aerodynamic probes, where semiconductor pressure sensors are mounted directly on the surface of the probes, using techniques which have previously been successfully used on the surface of rotor blades (Ainsworth, Dietz and Nunn [1991]). These are to be used to measure Mach number and flow direction in compressible unsteady flow regimes. In the first section, a brief review is made of the sensor and associated technology which has been developed to permit a flexible design of fast response aerodynamic probe. Following this, an extensive programme of testing large scale aerodynamic models of candidate geometries for suitable semiconductor scale probes is described, and the results of these discussed. The conclusions of these experiments, conducted for turbine representative mean and unsteady flows, yielded new information for optimising the design of the small scale semiconductor probes, in terms of probe geometry, sensor placement, and aerodynamic performance. Details are given of a range of wedge and pyramid semiconductor probes constructed, and the procedures used in calibrating and making measurements with them. Differences in performance are discussed, allowing the experimenter to choose an appropriate probe for the particular measurement required. Finally, the application of prototype semiconductor probes in a transient rotor experiment at HP turbine representative conditions is described, and the data so obtained is compared with (PD solutions of the unsteady viscous flow-field.

Experimental Characterization of Leading Edge Tubercles on Rotor Blades

2022 ◽  
Author(s):  
Ryley R. Colpitts ◽  
Dillon Hesketh ◽  
Ruben E. Perez
Keyword(s):  
Leading Edge ◽  
Rotor Blades ◽  
Experimental Characterization
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