Study On Air Bubble Removal By Filter Screen In An Open Oil Tank Of Lubrication System

The lubrication system delivers the clean lubricating oil to the surface of the relative moving parts,reducing the friction resistance in the system and reducing the wear of machine parts.Therefore,it is of great significance to enhance the lubrication performance of mechanical equipment to improve the reliability of mechanical equipment,prolong the service life of key parts and reduce the failure of mechanical equipment.When air is mixed into the lubrication system,the original ideal singlephase flow will be changed into gas-liquid mixed phase flow,and its flow properties will change greatly,which will seriously affect the stability of the lubrication system.In this paper,aiming at the generation and removal of air bubbles in the lubrication system,a measuring barrel device for air separation pressure of lubricating oil is designed to measure the air separation pressure of lubricating oil at different temperatures.Then,according to the actual working conditions of a marine lubricating oil tank,the visualized experimental study and numerical simulation of the flow field are carried out.The research results have guiding significance for the design of oil bubble removal in oil tank.The main contents of this paper are as follows:Aiming at the formation of bubbles in lubricating oil,a visual measuring barrel device for air separation pressure of lubricating oil was designed.The air separation pressure of l-hm46 hydraulic oil and 68 turbine oil at different temperatures was measured,and the bubble forming process of gas core was observed.The experimental results show that: for the same lubricating medium,the air separation pressure has a linear relationship with the oil temperature;bubbles are generally observed on the non smooth surface of the measuring barrel or on the surface of the small impurities in the oil.To verify the conjecture that the rough surface is easier to adsorb the gas core,the rough surface and smooth surface are placed in the barrel,and it is found that the bubbles are always on the rough surface or the surface of the fine particles It occurs first at the surface.Therefore,it is necessary to reduce the rough surface and impurities and the gas core attached to them in actual working conditions.Aiming at the phenomenon that a large number of bubbles appear in the oil tank of a marine lubricating system,a visual system for bubble removal of open oil tank filter screen is designed.The experimental measurement and numerical simulation of the degassing effect of two filters with a diameter of 0.15 mm are carried out.A certain amount of air is introduced into the lubrication system through the air filling device,and the oil bubble content before and after the filter screen is measured by sampling and standing method.It is found that the degassing rate of the first filter screen is 33.2% when it is vertically placed,and 51.94% when it is placed in an inclined position,so the degassing effect of the inclined filter screen is better;when the flow rate is the same,the liquid level difference caused by the inclined placement of the filter screen is small,so the inclined placement of the filter screen can improve the degassing effect The effect of pump oil absorption is smaller.Finally,using the FLUENT software VOF multiphase flow model and porous media model,and using the flow field similarity principle,the difficulties of multiphase flow and cross-scale calculation are overcome,and the numerical results of scaled three-dimensional flow field and two-dimensional flow field are obtained,which are in good agreement with the visualization experiment.