11 Next, for each style (fill thickness and mist diameter), the relationship between air flow velocity and collection efficiency is similar to graph 4, and each style reaches maximum efficiency at 1 to 2 m/s, and the efficiency tends to decrease due to re-accompanying at the allowable flow velocity. When actually using Demi Star, there are many mist types and the average diameter of mist is unknown, and there is a slight error in the above efficiency calculation, but if you take an example of water droplets and air systems, it looks like graph 5. As you can see from graph 5, it is difficult to collect and remove with high efficiency at mist diameters of 1 to 2 μm or less, and it is necessary to increase the number of layers in order to achieve satisfactory effects. Collection efficiency Demi Star's theoretical formula for collection efficiency has been published by C, L, Carpenter, etc. E＝ １－ （1 －Et/C）N …………Equation (3.1) C = N/k2F ……………………Equation (3.2) E ：Demi Star's theoretical capture efficiency Et ：Mist collision efficiency C for one line of Demi Star ：Modification characteristics of Demi Star (Table 3) N ：Number of filling layers k2 ：Non-dimensional ratio F ：It is known that Et is affected by the line diameter, mist diameter, operating conditions, etc., and that there is a relationship between the Stalk number K and Et defined by the following formula. ……………Equation (3.3) K ：Stokes number ρl ：Mist density kg/m3 U ：Airflow speed m/s dl ：Mist diameter m μg ：Fluid viscosity Pa・s Df ：The theoretical efficiency E obtained from the line diameter m equation (3.1 to 3.3) matches well with the experimental values, and the collection efficiency can be estimated from the parameters and variables associated with the actual usage conditions of Demi Star. From graph 3, Et can be approximated by the following equation as a function of K. ……Equation (3.4) However, as can be seen from the above relations, the airflow velocity, mist diameter, and mist properties are closely related to the collection efficiency. （dℓ）2ρℓU K＝1 9 μgDf 1 －10 Et＝ －0.22(log 10K）2
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