What are the characteristics of Hydro Power Plant cavitation erosion?
The cavitation phenomenon of the Hydro Power Plant is a special phenomenon produced by the water flow during the energy conversion process. Around the beginning of this century, it was discovered that the high-speed metal propeller of the ship was destroyed in a short period of time. Later, the runner blade was damaged in the Hydro Power Plant, and the phenomenon of cavitation began to be discovered and valued.
The working medium of the Hydro Power Plant is liquid. Liquid particles do not vibrate around a fixed position like solids, but the migration of particle positions occurs more easily. At room temperature, the liquid shows this characteristic. The separation of liquid particles from the liquid depends on the vaporization characteristics of the liquid. For example, when water reaches 100 ° C under a standard atmospheric force, boiling vaporization occurs, and when the ambient pressure drops to 0.24mH2O, cavitation can occur.
Since the liquid has vaporization characteristics, when the liquid is heated at a constant pressure, or the pressure of its surrounding environment is reduced by static or dynamic methods at a constant temperature, the liquid can be vaporized. However, when studying cavitation and cavitation erosion, the vaporization of liquid formed by these two different conditions is conceptually different. Any kind of liquid is heated under a constant pressure. When the temperature of the liquid is higher than a certain temperature, the liquid begins to vaporize and form bubbles, which is called boiling. When the temperature of the liquid is constant, when the pressure is reduced to a certain critical pressure, the liquid will also vaporize or the air dissolved in the liquid will develop into cavities. This phenomenon is called cavitation.
The cavitation phenomenon that we usually talk about before actually includes two processes of cavitation and cavitation. Cavitation is the formation of cavities in the liquid that disrupts the continuity of the liquid phase fluid. It occurs in the flow region where the pressure drops to a certain critical value. The cavity is mainly filled with liquid vapor and gas precipitated from the solution. When these cavities enter a lower pressure area, they begin to grow into larger bubbles. Then, the bubbles are brought to the area where the pressure is above the critical value by the fluid, and the bubbles will collapse. This process is called cavitation. The cavitation process can occur inside the liquid or on a fixed boundary. Cavitation refers to the destruction of the material on the overcurrent surface due to the collapse of cavitation. The collapse of the vacuole is accompanied by mechanical, electrical, thermal, chemical and other processes. Cavitation is a direct consequence of cavitation, and it only occurs on solid boundaries.
