Cutting metal material
In the impression of most people, water knives are a kind of processing method for cutting workpieces with particularly high pressure water. If you ask the water knife manufacturer, your water knife can achieve how high pressure Ah, it is certain that our water knife normal working pressure in 400 MPa, maximum pressure can reach 420 MPa! We eat the melon masses certainly exclaim, so big pressure Ah, this must be how terrible Ah! Today we will uncover the "true face" of 400 MPa ultra-high pressure water.
The reason why the water knife can cut the material is not because of its pressure. So what is it? The reason why the water knife can cut the material is because the speed of water flow at the exit of the water knife Gemstone hits the mouth is nearly three times the speed of sound(800-1000m/s), mainly using the kinetic energy of water to cut it, not the pressure energy of water. After the high pressure water passes through the Gemstone nozzle, the pressure is almost zero! In summary, in fact, the cutting process of the water knife is a supersonic process of water jet erosion of materials. The energy that directly destroys the material is the kinetic energy of water, not the pressure energy.
Of course, writing so much is not to express the 400 MPa water pressure is a "pseudo-concept," but to let everyone know that the direct damage to the workpiece is not pressure, but the kinetic energy of water. However, the reason why the water jet has such a large amount of kinetic energy is mainly converted by the pressure energy of high-pressure water. The device that realizes energy conversion is the Gemstone nozzle. As for why you want to explain this knowledge point, because in the recent exchange with a hydraulic engineer who has worked in the water knife industry for more than 10 years, he actually believes that the speed of water from the Gemstone nozzle can not exceed the speed of sound. He also despised me during this period. It sounds a bit sad!
In the end, we may see more water knives for cutting glass, Stone, steel plates, etc.. Let's look at its application in the food industry today! Here are a few pictures for everyone to look at.
Cut the cake.
Cut the Apple.