Research On The Influence Factors On The Resistance Characteristics Of Multi-layer Wire Mesh Air Filter

Multi-layer wire-mesh filter is one of the important components of marine air intake systems. It has a very high removal efficiency especially for small droplets (usually ranges from 2?m to 101?m) while other types of separators as vane separator or cyclone separator couldn't remove droplets of such diameters easily. At the same time, a great proportion of flow resistance could be contributed by wire-mesh filter. The flow resistance characteristics of wire-mesh is influenced mainly by three of its' structural parameters: wire diameter, layer spaces and mesh spaces. it makes sense to understand how each of these parameters influence flow resistance because it is helpful to the optimal design of wire-mesh filters. In this work,the flow resistance characteristics of wire-mesh filters is studied numerically,following steps were included:1. The precision of simplified geometrical model—two dimensional model is analyzed by establishing wire-meshes of different numbers of layers (20,40,60,80,100 and 120 layers)using equal-probable random number method created by former investigators. By observing relative errors of pressure drops between different sets of random numbers at the same number of layers, the influence of randomicity could be understand and the stability of calculation results could be evaluated. By comparing the multiple number of pressure drop of 40-120 layers' wire-mesh to that of the 20 layers, the rationality of pressure drop's rising trend with number of layers could be evaluated.2. An improvement were made to the traditional equal-probable random model, the old way of acquiring random numbers was replaced by a new method—grouping the random numbers and generate random ordinal two times. Using this new method, wire-mesh of different number of layers were established again, a more stable and linear calculation results of pressure drop were acquired. Thus the influence of the number of layers together with the orderliness of random number was analyzed.3. 125 wire-mesh pads of different structural parameters were established including five kinds of wire diameters (0.04mm,0.06mm,0.08mm,0.10mm and 0.12mm), five kinds of layer spaces (0.2mm,0.4mm,0.6mm,0.8mm and 1.0mm) and five kinds of mesh spaces(1.6mm,1.8mm,2.0mm,2.2mm and 2.4mm). Then pressure drops of each pads were calculated under five different inlet air speeds (2m/s?4m/s?6m/s?8m/s and lOm/s). The influence pattern of each parameter on the flow resistance characteristic were then analyzed through the observation of the flow fields and data categorize.4. Based on the large quantity of simulation data, an empirical expression predicting the pressure drop of wire mesh related to wire diameter, layer space and mesh space was deduced.The precision of the expression was validated by comparing its data to the experimental data.Then the validity of the improved two-dimensional random model is proved by comparing the simulated data to the expression data.