| With the development of computer technology and automatic control technology, non-cutting time in metal-cutting fields has been reduced greatly. But because of cutting tool wear, the time for changing the tools frequently has became the primary factor in the restriction of enhancing the metal-cutting efficiency. For a long time, the people are accustomed to reduce the cutting tool wear by using cutting fluid for cooling or lubricating. However, with the continuous improvement of environmental protection and sustainable development requests, the traditional manner of cutting fluid used is restricted more and more so that new green cooling lubrication ways is in the urgent needs for satisfying the request of the machining efficiency.At present, minimum quantity lubrication (MQL) is one kind of green cooling lubrication technology which is mature and applied widespread and its cooling lubrication effect directly controlled by the atomizing degree of the cutting fluid. The traditional atomizer nozzle is difficult to achieve the desired spraying effects because of the coolant fluid viscosity. The effervescent atomize based on the principle of bubble atomizing spray nozzle (with mixer) overcomes such deficiencies and works with characteristics of low-pressure, low-liquid consumption and high spry quality. But the theory and applied research about the effervescent atomize is imperfect. In this paper, referring to the development of the MQL cutting system, taking the effervescent atomize as the object of study, the flow field characteristics and atomization characteristics of atomization nozzle (mixer) and external (downstream of the nozzle) were analyzed with fluid dynamics software—FLUENT and a kind of atomization MQL machining system was designed, at last, giving some cutting experiments. The result has certain significance for the effervescent atomize research and application.Based on the basic theory of liquid atomization and the principle of effervescent atomize, using the pre-treatment software named Gambit of FLUENT, the paper was achieved geometric model and mesh for the internal and external flow field of the effervescent nozzle and used FLUENT general multiphase flow model - the hybrid model to analysis nozzle flow characteristics, presenting the internal flow nozzle pressure field, velocity field and gas-liquid component distribution, proving that exists even bubbles within the nozzle by analyzing flow field characteristics and mixing effect of effervescent atomize; Besides, the flow field and atomization characteristics in the nozzle downstream was simulated by using discrete phase model (DPM) of FLUENT. The speed field distribution, particle size distribution and spray angle and the impacts of operating parameters on them were studied. Obtaining the rule about the speed field distribution, the particle size distribution and the atomization angle go along with the operating parameters in the exterior flow field of spray nozzle.Based on the study above, the effervescent atomize structure design and parameter selection was improved and one set of cutting system of bubble atomization MQL was designed, and the drilling and milling tests to Z107 Al-Si alloys and steel 45 respectively was done using high-speed steel cutting tools with advanced coatings and cutting performance and wear characteristics of the tool was analyzed. The result show that the ship sticking phenomenon reduces obviously and the escape of chips is smooth when drilling Al-Si alloys, the coating performance superiority can display fully; for steel 45, the tool wear, especially the boundary wear of main cutting edges is improved, which is good for prolong the tools life.
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