Correlation Between Mechanical Properties and Cavitation Erosion Damage of Carbide and Nitride Thick Coatings for Turbomachinery Applications

2020 ◽  
pp. 439-455
Author(s):  
Vladimir Safonov ◽  
Anna Zykova ◽  
Janusz Steller ◽  
Tomasz Seramak
Keyword(s):  
Mechanical Properties ◽  
Cavitation Erosion ◽  
Erosion Damage ◽  
Thick Coatings

A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - Damage to solids caused by cavitation

1966 ◽  
Vol 260 (1110) ◽  
pp. 245-255 ◽  
Keyword(s):  
Mechanical Properties ◽  
Cavitation Erosion ◽  
Cavitation Resistance ◽  
Steam Turbines ◽  
Single Event ◽  
Cavitation Damage ◽  
Erosion Damage ◽  
Highly Sensitive ◽  
Wide Range ◽  
The Impact

This paper describes the early stages of cavitation damage observed in cavitating venturi tunnels. The cavitating fluids were water and mercury, and a wide range of specimen materials were used. The damage was found to consist of single-event symmetical craters and irregular fatigue-type failures. The degree of damage was highly sensitive to minor flow perturbations, and this is discussed. The effect of stress level in the specimen before testing, and relations between cavitation resistance and the mechanical properties of the materials are considered.

A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - The resistance of materials to impact erosion damage

1966 ◽  
Vol 260 (1110) ◽  
pp. 193-203 ◽  
Keyword(s):  
Mechanical Properties ◽  
Mass Loss ◽  
Incubation Period ◽  
Turbine Blade ◽  
Cavitation Erosion ◽  
Steam Turbines ◽  
Microstructural Characteristics ◽  
Erosion Damage ◽  
The Impact ◽  
Impact Erosion

The behaviour of established and potential turbine blade and erosion shield materials subject to impact erosion by water droplets of controlled size has been investigated over a range of impact velocities up to 1040 ft./s. Both the topographical form and the microstructural characteristics of damage have been studied, and correlated with the conditions of the test and the mechanical properties and phase constitution of the materials. It has been found that the rate of erosion, as measured by mass loss, changes during the course of a test. An initial incubation period is generally followed, successively, by periods of increasing, constant, and then decreasing rates of erosion, possibly culminating in a second steady, but lower, rate of erosion.

scholarly journals Vibrational Stresses of Damaged Steam Turbine Blades After Renovation Repair

2021 ◽  
Vol 24 (1) ◽  
pp. 42-52
Author(s):  
Mykola H. Shulzhenko ◽  
◽  
Anton S. Olkhovskyi ◽  
Keyword(s):  
Mechanical Properties ◽  
Strain State ◽  
Turbine Blades ◽  
Excitation Frequency ◽  
Physical And Mechanical Properties ◽  
Erosion Damage ◽  
Trailing Edges ◽  
Blade System ◽  
Last Stage ◽  
Maximum Stresses

The last-stage blades of K-1000-60/3000 steam turbines operate in a humid steam environment, which causes erosion damage in the blades and reduction in their residual life. The relevance of this work is related to the need to continue the safe operation of such turbine blades. A number of variants of the finite-element models of individual blades and last-stage blades in the disk-blade systems of the above turbines are considered. Results of the numerical study of the influence of blade part removals in erosion damage zones after renovation repair on the vibration characteristics of individual blades and blades in the disk-blade system are presented. An analysis of the stress-strain state under the conditional load from the steam flow during the forced oscillations of individual blades and blades in the disk-blade system is carried out. The loads are given as evenly distributed and linearly variable on blade surfaces. The dependence of the maximum equivalent vibration stresses on excitation frequency is determined. It is assumed that the physical and mechanical properties of the blade material are preserved (as for the original version) after the renovation repair of blades and processing of their surfaces. There is a significantly greater reduction in the vibration stresses of blades in the disk-blade system than in the stresses of individual blades. Graphs of the dependence of the maximum stresses on excitation frequency both for undamaged individual blades and blades in the disk-blade system after their renovation repair are given. Various variants of blade part removals in areas of blade leading and trailing edges are considered. It is shown that with decreasing chords of blades after renovation repair, frequency regions of increased vibration may appear in lower blade parts. In the lower parts of individual blades and blades in the disk-blade system, the maximum stresses increase in comparison with their values in undamaged blades. With the change in the stress-strain state of rotor blades in comparison with the original version of undamaged blades, the possibility of extending their safe lifetime in case of multi-cycle fatigue is assessed. The safe lifetime of the considered blades with a chord of at least 150 mm after their renovation repair can be extended according to their stresses, if the cyclic symmetry of the disk-blade system is not violated, and the physical and mechanical properties of the material are preserved after the processing of damage removal zones on blade trailing edges.

Production of cavitation erosion damage by means of an electromagnetic shock wave source.

2009 ◽  
Vol 125 (4) ◽  
pp. 2561-2561
Author(s):  
Qi Wang ◽  
Nicholas J. Manzi ◽  
R. Glynn Holt ◽  
Ronald A. Roy ◽  
Robin O. Cleveland
Keyword(s):  
Shock Wave ◽  
Cavitation Erosion ◽  
Wave Source ◽  
Erosion Damage ◽  
Electromagnetic Shock ◽  
Electromagnetic Shock Wave
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