Re Deposition Comparison of Theory with Experiment

An analytical solution to (3.33) does not seem possible, but a solution can be obtained for the region near the forwiird stagnation point (Fig. 3.1). Near the streamline In the plane of symmetry which leads to the stagnation point, sin x vanishes and cos a i approaches unity so (3.50) becomes 

The solution to (3.40) with the.se boundary conditions gives the following expression for the coefficient of mass transfer at the forward stagnation point  

Although this result applies only at — 0, the deposition rate is greatest at this point and illustrates the general functional dependence on Pe and Re over the entire cylinder. 

Rearraiiginy and integrating Jrmn - = U to - L. the ihicknesfi of the filter is given by 

Because the fiber diameters are usually not all equal and the fibers are arranged in a more or less random fashion, i)n should be inteipreted a,s an effective fiber efficiency that cun be calculated from (3.44) and ba.sedon an average diameter, r7, usually the arithmetic average. In an experimental deiermination of t/fj. the practice is to measure N and /V2, the inlet and outlet concentration of a nionodispcrse aerosol passed through the filter. The average fiber diameter, d, can be determined by microscopic examination. 

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