Answer 1. The lowest pressure in the unit pump is located near the impeller inlet. When the pressure is reduced to the saturated air pressure of the temperature at that time, the liquid begins to vaporize and a large amount of bubbles are relieved from the liquid. When the bubble flows to the high -pressure area of the pump, under the action of external pressure, the bubbles suddenly condense into liquid. At this time, the liquid around the bubbles is rushed towards the original time of the original air bubble at a very high speed, and a large hydraulic impact was produced. Because there are many bubbles coagulated per second, many great impact pressures are generated. Under this continuous local impact load, the surface of the overcurrent parts in the pump is gradually fatigue and damage, and many eroded numbers appear. Then the continuous slices are honeycomb -shaped, and finally the phenomenon of peeling. In addition to the damage caused by impact, while the liquid is vaporized, it also precipitates the oxygen dissolved in it, which will oxidize the oxidation of overcurrent parts.

This phenomenon that is destructive by mechanical erosion and chemical corrosion is the phenomenon of vapor etching.

Answer 2. At a certain temperature, the liquid is generated when the pressure is reduced to the vaporization pressure at the temperature. This phenomenon of bubbles is called steam erosion.

Answer 3. Qin erosion refers to when the pressure of the leaf surface of the storage groove is certain. If the pressure of the center of the impeller is reduced to equivalent to the saturated steam pressure at the current temperature of the transport liquid, the liquid at the import of the impeller will appear a large amount of bubbles. After the liquid enters the high -pressure zone, it is quickly crushed and condensed, causing the space where the bubbles are located to form a vacuum. The surrounding liquid mass point is rushed towards the center of the bubble at a great speed, causing instant impact pressure, which causes the impeller to be damaged quickly and accompanied by accompanied There are pump vibrations, noise, pump traffic, raising and efficiency significantly declined. This phenomenon is called air erosion phenomenon.

Answer 4. If it is a pump, the height between the pump and the water surface should be reduced. The hydraulic cylinder mixes a certain amount of air in the liquid between the piston and the guidance case during the working process. As the pressure gradually increases, the gas in the liquid will turn into a bubble. When the pressure rises to a certain limit value, these air bubbles will break down under high pressure, thereby quickly affecting high temperature and high pressure gases to quickly to effectively act to the rapid effect of gases to quickly. On the surface of the parts, the hydraulic cylinder causes air erosion and causes corrosive damage to the parts. This phenomenon is called air erosion phenomenon.