Particle-to-gas mass flow rate ratio

The materials used in the experiments are millets and rapeseeds, the properties of which are identical to those listed in Table 3.1 (Chapter 3). All the experiments were carried out at room temperature, and the operating or structural conditions tested ranged as follows the velocity of the airflow in the accelerating tube w0= 9.48-17.36 m-s particles to gas mass flow rate ratio mp/ma = 0.556-1.0, and the dimensionless impinging distance SldiK = 3.0-6.7. 

It is clear from Fig. 4.5 that the data for ,c>p are considerably concentrated over 85% of the values are in the range 4.3 to 6.2, and the average value is 5.34. This fact indicates that ,c>p can be considered to remain essentially constant and that, consequentially, Eq. (4.11) describes well the pressure drop behavior due to the acceleration and collisions of the particles. Therefore the combined consideration of the two kinds of collisions, i.e., the collisions of particles on the wall and between particles, is reasonable and feasible. It should be noted that, as described by Eqs. (4.5) and (4.6), for a given impinging velocity u0, the velocity of particles at the outlet of the accelerating tube depends on the length of the tube Lac, the particles to gas mass flow rate ratio and the mean diameter of particles dv. Therefore Eq. (4.11) actually... 

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