Impact of an oil coating on particle deposition and dust holding capacity of fibrous filters

Pressure Drop Dynamics during Filtration of Mixture Aerosol Containing Water, Oil, and Soot Particles on Nonwoven Filters

The pressure drop dynamics during the filtration of three-component mixture aerosols are investigated and compared with two and single-component aerosols. The main area of interest is the effect of the addition of a small quantity of liquid (oil) and solid (soot) particles during the filtration of aerosol containing water mist. In addition, calculations of the change in filter mass during oil aerosol filtration have been carried out and compared with the experimental results. The new, improved filtration efficiency model takes into account a better coefficient fitting in the filtration mechanism equations. The limitations in the change in fibre diameter and packing density resulting from the filter loading have been implemented in the model. Additionally, the calculation model employs the fibre size distribution representation via multiple average fibre diameters. The changes in fibre diameter are dependent on each fibre’s calculated filtration efficiency. The improved filtration model has been utilised to predict the mass change of the filters during the filtration of pure and mixture aerosols. The pressure drop calculation model based on changes in filter mass has been formulated. The model is then utilised to calculate pressure drop changes resulting from the filtration of the oil aerosol and water and oil mixture aerosol.

Experimental and Theoretical Research on Pressure Drop Changes in a Two-Stage Air Filter Used in Tracked Vehicle Engine

The effect of mineral dust in the air sucked in by an engine on accelerated component wear and reduction in performance was presented. The necessity to use two-stage air filters (multicyclone-paper insert) for military vehicles was shown. The results showed that placing an air filter in the path of the air entering the engine causes an additional pressure drop (air filter resistance increase), which leads to engine power decrease and increased fuel consumption. An analysis of model filter beds’ pressure drop changes (depending on bed parameters, aerosol flow parameters, and dust content) was carried out. It was revealed that it is very difficult to model changes in pressure drop in filter beds for actual conditions that appear during vehicle operation. The air filter pressure drop measurement results of more than 20 tracked vehicles operating in variable air dust concentration conditions were presented. The forms of selected regression models of the “life curve” type, best suited to the actual changes in air filters pressure drop as a function of the vehicle mileage, were determined. Significant differences were found between the same model values for different units of the tested vehicles. The quality of forecasting pressure drop value by selected functions was assessed by extrapolating them to the value of the next measurement and comparing the forecast and actual value. It was found that for the performed experiment, sufficiently good results of experimental data approximation and forecasting were obtained for a simple linear model.