Geometric parameters of influence on rotor stator interaction in radial hydraulic turbines

One possible way to improve the aerodynamic performance of turbomachines is to analyse and generalize existing results obtained from design and testing. These can be applied to develop a quantitative relationship between the geometry of various regions of the flow path and turbomachine performance. An optimal correlation between various geometric parameters can be established in this manner. By studying blade geometry of various kinds of axial turbomachine (compressors, gas turbines, hydraulic turbines and pumps), the author has found some regularities in their geometry which enabled the design of highly efficient blades. Regularities in the twisting of impeller blades of axial compressors working over a wide range of Mach numbers are represented in this work. Information is presented showing that analogous regularities exist also for axial hydraulic turbine and pump blades.

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Characterization of the Effects of Ingested Bodies on the Rotor–Stator Interaction of Hydraulic Turbines

Energies ◽

10.3390/en14206669 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6669

Author(s):

Alfredo Guardo ◽

Alfred Fontanals ◽

Mònica Egusquiza ◽

Carme Valero ◽

Eduard Egusquiza

Keyword(s):

Fluid Dynamics ◽

Experimental Data ◽

Pressure Pulsation ◽

Correct Diagnosis ◽

Mechanical Damage ◽

Pressure Pulsations ◽

Pump Turbine ◽

Rotor Stator Interaction ◽

Hydraulic Turbines

Runner and distributor blockages in hydraulic turbines occur due to the ingestion of external bodies such as rocks or logs. These obstructions can change the amplitude and uniformity of the pressure pulsations in the machine, creating large unbalanced forces that can lead to reduced efficiency, increased vibration and mechanical damage. In this paper, the effects of obstructions caused by ingested bodies in the runner and the distributor of a pump turbine on its internal pressure pulsation were investigated by means of computational fluid dynamics. A numerical model of an unobstructed pump turbine is presented and validated against experimental data. Several cases of runner or distributor blockage were studied, and their RSI pressure pulsations were recorded and analyzed at different locations. The results obtained allow us to characterize the effect of these blockages on the machine’s RSI, which can be helpful for the correct diagnosis of these types of damage.

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Lectin-Induced RBC Agglutination: Chemical vs. Cryofixation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002920 ◽

1980 ◽

Vol 38 ◽

pp. 664-665

Author(s):

Dean A. Handley ◽

Lanping A. Sung ◽

Shu Chien

Keyword(s):

Lectin Binding ◽

Freeze Substitution ◽

Electrostatic Charge ◽

Geometric Parameters ◽

Comparative Approach ◽

Chemical Fixation ◽

Cell Surfaces ◽

Minimal Cell ◽

Membrane Stiffness ◽

Cell Contour

RBC agglutination by lectins represents an interactive balance between the attractive (bridging) force due to lectin binding on cell surfaces and disaggregating forces, such as membrane stiffness and electrostatic charge repulsion (1). During agglutination, critical geometric parameters of cell contour and intercellular distance reflect the magnitude of these interactive forces and the size of the bridging macromolecule (2). Valid ultrastructural measurements of these geometric parameters from agglutinated RBC's require preservation with minimal cell distortion. As chemical fixation may adversely influence RBC geometric properties (3), we used chemical fixation and cryofixation (rapid freezing followed by freeze-substitution) as a comparative approach to examine these parameters from RBC agglutinated with Ulex I lectin.

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Analysis of the Rotor-Stator Interaction in a Radial Flow Pump

La Houille Blanche ◽

10.1051/lhb/2009067 ◽

2009 ◽

pp. 141-151 ◽

Cited By ~ 10

Author(s):

G. Cavazzini ◽

G. Pavesi ◽

G. Ardizzon ◽

P. Dupont ◽

S. Coudert ◽

...

Keyword(s):

Radial Flow ◽

Rotor Stator Interaction ◽

Radial Flow Pump ◽

Flow Pump

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Evaluation of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings by the multi-frequency radio wave method of a slow surface electromagnetic waves

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-8-51-58 ◽

2020 ◽

pp. 51-58

Author(s):

Aleksandr I. Kazmin ◽

Pavel A. Fedjunin

Keyword(s):

Radio Wave ◽

Noise Level ◽

Electromagnetic Waves ◽

Dielectric Materials ◽

Geometric Parameters ◽

Experimental Investigations ◽

Wave Method ◽

Dielectric Coatings ◽

Surface Electromagnetic Waves ◽

Multilayer Dielectric

One of the most important diagnostic problems multilayer dielectric materials and coatings is the development of methods for quantitative interpretation of the checkout results their electrophysical and geometric parameters. The results of a study of the potential informativeness of the multi-frequency radio wave method of surface electromagnetic waves during reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings are presented. The simulation model is presented that makes it possible to evaluate of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings. The model takes into account the values of the electrophysical and geometric parameters of the coating, the noise level in the measurement data and the measurement bandwidth. The results of simulation and experimental investigations of reconstruction of the structure of relative permittivitties and thicknesses of single-layer and double-layer dielectric coatings with different thicknesses, with different values of the standard deviation (RMS) of the noise level in the measured attenuation coefficients of the surface slow electromagnetic wave are presented. Coatings based on the following materials were investigated: polymethyl methacrylate, F-4D PTFE, RO3010. The accuracy of reconstruction of the electrophysical parameters of the layers decreases with an increase in the number of evaluated parameters and an increase in the noise level. The accuracy of the estimates of the electrophysical parameters of the layers also decreases with a decrease in their relative permittivity and thickness. The results of experimental studies confirm the adequacy of the developed simulation model. The presented model allows for a specific measuring complex that implements the multi-frequency radio wave method of surface electromagnetic waves, to quantify the potential possibilities for the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric materials and coatings. Experimental investigations and simulation results of a multilayer dielectric coating demonstrated the theoretical capabilities gained relative error permittivity and thickness of the individual layers with relative error not greater than 10 %, with a measurement bandwidth of 1 GHz and RMS of noise level 0,003–0,004.

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