Laser-driven test method for anti-cavitation performance of material surface

Abstract

Laser-driven material surface cavitation resistance test method, including: 1) fixing the sample to be tested on the fixture, adjusting the spatial position and inclination angle of the fixture; 2) adding water to the water tank, using a magnetic stirrer Stir the water body until it is evenly stirred, and then the high-pressure water generator generates a water jet and shoots it to the surface of the sample to be tested to generate water hammer and shock wave action; 3) Start the laser light source of the laser, and the laser pulse energy acts on the sample to be tested In the water jet above, a local high temperature is generated, and the liquid in the laser spot generated by the laser focusing is vaporized instantaneously to form bubbles. Bubbles grow up and collapse in the water jet, and instantly release high-temperature and high-pressure micro-jet, which produces severe cavitation and activation effects on the surface of the test sample. The invention can take into account droplet shock wave, water hammer action, cavitation effect and activation effect, and comprehensively reflect the anti-cavitation performance of the sample to be tested.

Description

technical field [0001] The invention belongs to the technical field of cavitation resistance evaluation of materials, and in particular relates to a method for testing the cavitation resistance performance of material surfaces. Background technique [0002] During the actual service process, the last stage blade of the steam turbine is subjected to cavitation by the wet steam containing water droplets and fine particles for a long time. Secondary water droplets entrained in the steam flow hit the running final blade at high speed, which will cause honeycomb-shaped defect tissue on the edge of the blade, especially the top of the steam inlet side and the root of the steam outlet side of the blade, and then form a large number of tiny cracks. As a result, the anti-fatigue performance of the blade is reduced, thereby changing the vibration characteristics of the blade, weakening the strength of the blade, and deteriorating the aerodynamic performance of the blade. This deterio...

AI Technical Summary

Problems solved by technology

The above test equipment and means can only realize the test of the effect of a single gas or liquid drop on the material, but cannot comprehensively evaluate the anti-cavitation performance of the blade material in the actual working condition

[0005] In addition, during the actual service process of the last stage blade, when the bubbles existing in the liquid phase collapse, the high-temperature and high-pressure micro-jet is released instantaneously within microseconds to nanoseconds, causing severe cavitation on the surface of the material effect and activation effect, and the patent: "A Material Cavitation Resistance Test System" (Application Publication No.: CN 106323851 A, Application Publication Date: 2017.01.11) is impossible to simulate only by high-pressure water nozzles and high-pressure gas nozzles The cavitation effect and activation effect of the final stage blades of the steam turbine in the actual service process are not consistent with the actual service conditions of the steam turbine unit

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