Mixing for reaction injection molding II. Impingement mixing of fiber suspensions

The performance of confined impinging jet mixers on suspensions of milled glass fibers in Newtonian liquids is investigated experimentally. Also studied are the performance of these devices in conjunction with an impingement aftermixer and a rotating mechanical mixing aid. In contrast to the behavior of unfilled liquids, fiber suspensions exhibit significant large‐scale mixing defects. Over the range of fiber lengths and loadings tested, large‐scale mixing quality is found to be dependent on an effective Reynolds number based on the shear viscosity of the suspension at a strain rate characteristic of the length of fibers. Both mixing aids are shown to provide improved mixing quality and could be useful in situations where length of fibers. Both mixing aids are shown to provide improved mixing Quality. and could be useful in Situations where an impingement mixer alone is not adequate.