| As the global energy and environmental pressure intensifies,the recycling of non-renewable resources represented by oil has been highly valued by many countries,and sustainable development of oil purification technology has received widespread attention from concerned industries.The hydraulic lubrication system is widely used in machinery,power and other industrial equipment,and a large number of impurity particles and other pollutants are generated during running,easily causing equipment failures.The enterprises generally adopt the method of overall oil replacement or online purification,which consumes large resources and causes serious environmental pollution.Benefited from no consumables and environmental protection,the electrostatic oil purification technology has been successfully applied for purifying low-pollution oil such as aviation hydraulic oil and transformer oil.However,in consideration of relatively high oil pollution,complex oil characteristics and constant changes when the hydraulic lubrication system is running,the liquid-solid separation mechanism for electrostatic oil purification is very complicated.The existing technical equipment features low oil purification efficiency and high purification difficulty.Therefore,in order to develop the key liquid-solid separation technology in the hydraulic lubrication system,there is a need to develop high-efficiency electrostatic oil purification technology and equipment applicable for high-pollution oil.In this paper,the electrostatic purification mechanism for oil from the hydraulic lubrication system was analyzed,and a physical purification model was built.Through numerical simulation and experimental research,the main factors affecting the oil purification efficiency and the liquid-solid separation mechanism were analyzed.An electrostatic oil purification experimental device for high-pollution oil was invented,and an industrial prototype of the electrostatic oil purification system was designed and completed.Besides,the experiments on oil purification efficiency and industrial application were carried out.The research results were of important theoretical and practical significance for the research on liquid-solid separation in an electric field and the application of high-voltage electrostatic oil purification technology in the hydraulic lubrication system.The major research content of this paper is as follows:1.By analyzing the high-voltage electrostatic oil purification mechanism,a mathematical purification model was built,and the main factors affecting the oil purification efficiency and the liquid-solid separation mechanism were obtained through numerical simulation.The results showed: that the linear-cylindrical electrode drum type dust collecting body had a better non-uniform electric field,conducive to improving the purification efficiency;during electrostatic purification,the influence of the voltage,flow,particle size,particle content and other factors on the purification efficiency was analyzed by using this model.The results showed that when the purification flow was set to 1.5L/min,3L/min and 4.5L/min,the purification efficiency decreased with the increase of the flow rate.When the voltage was set to 1k V,10 k V and 20 k V,the purification efficiency increased with the increase of the voltage.The physical purification model presented an obvious purification effect for 0.5-15?m impurity particles.When the solid volume fraction was greater than 0.000125,the model presented an obvious purification effect.2.Through dimensionless analysis,the physical purification model was built.an electrostatic oil purification experimental device was built.Purification efficiency experimental research was carried out on typical oil samples into the hydraulic system,and the influence of key factors on the purification efficiency was analyzed.For four types of typical oil samples in the hydraulic lubrication system: machine tool oil,anti-rust oil,hydraulic oil and bearing oil,the influence of key factors on its purification efficiency was studied through experiments.The experimental results showed that the voltage was in the range of 5k V-15 k V,and the purification efficiency of each oil sample was increased with the increase of the voltage.The purification efficiency for high-viscosity bearing oil samples was most obviously improved;the purification efficiency of bearing oil samples increased with the increase of oil temperature at20?-60?,while the purification efficiency of other oil sample changed little;as the flow rate(1L/min-5L/min)decreased,the purification efficiency of each oil sample showed an upward trend.Among them,the purification efficiency of 5-15?m particles in each oil sample significantly changed.3.Through orthogonal experiments on electrostatic oil purification,the key factors were evaluated and optimized,and the purification effect of the electrostatic oil purification experimental device was verified.The subordinate relationship and the optimal combination of influence factors such as voltage,flow,temperature and purification time were studied during orthogonal experiments.The experimental results showed that voltage and purification time were the main influence factors,and the flow and temperature were minor influence factors;under the optimal combination of influence factors,the purification efficiency verification experiment was carried out.The experimental results showed that the purification rate of 5-15?m,15-25?m and 25-50?m particles was 96.9%,84.9% and 60% respectively.4.Based on theoretical and experimental research,an industrial prototype of the high-voltage electrostatic oil purification system was invented from the electrostatic oil purification experimental device,and the application effect of the prototype in the field hydraulic lubrication system was verified through field experiments.Firstly,a new multi-mechanism electrostatic oil purification device was invented from the original electrostatic oil purification device based on the particle charge balance principle.On this basis,a pre-filter,water removal device and purification monitoring device were designed,and an industrial prototype of the high-voltage electrostatic oil purification system was finally designed and completed.The experimental results showed that: the purification rates of impurity particles of 5-15?m,15-25?m,25-50?m,50-100?m and >100?m were 93%,83%,91%,98% and 86% respectively.The experimental results verified that the industrial prototype of the high-voltage electrostatic oil purification system presented a good purification effect in the field hydraulic lubrication system with high pollution and changing oil characteristics. |
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