Numerical And Experimental Study On The Atomization Of The Nozzle Used In Minimum Quantity Lubrication Grinding

In grinding process, due to the high grinding energy ratio, it is easy to generate a lot of heat in the grinding zone. Moreover, the heat is usually hard to be taken away in time, which can lead to high temperature in the grinding zone and then influence the quality of the component and life of the grinding wheel. Some scholars had proposed the minimum quantity lubrication(MQL), which is to spray a small amount of vegetable oil or biodegradable synthetic ester to the tool tip with compressed air. However, as the high speed of the grinding wheel, the gas barrier layer formed during grinding may prevent the grinding fluid entering the grinding zone. At present, the paper of MQL grinding or the air barrier layer is still rare.In this article, the atomization theory of grinding fluid is studied and the mathematical model is established. The structure including the side-mix structure and “double-spout” structure of grinding nozzle is proposed, and then the Simulation model of the nozzle is established. The mathematical simulation of spraying is conducted. The main achievements are as follows:(1) The atomization theory of liquid is analyzed, and the two-stage atomization model is established based on Kelvin-Helmoholtz instable theory. The first stage of the atomization model is the theoretical arithmetic of the particle size distribution. And the second stage is to import the results of calculation to the gas field and conduct the spraying simulation.(2) A new structure of grinding nozzle is proposed, the working principle of which is studied. And then the relevant geometric model is established.(3) The inner and outer flow field is set up by computational fluid dynamics theory. Base on that, the relevant simulation is conduct. The key point of the simulation is how the structure of the nozzle influence the gas field and the atomization results.(4) The simulation results is verified by experiment. The results show that the particle size distribution of simulation and experiment are basically the same, which verify the rationality of the two-stage atomization model.