Jet Impingement Mixers

Reactor 23 [R 23] [Impinging-jet Micro Mixer Tube] - Reaction System... 

The impinging-jet micro mixers are constructed as a cylindrical block comprising two feed tubes which become smaller towards the outlet [48]. Accordingly, the main characteristics of these mixers are the diameter of the outlet bore, the interspaces between the bores and the angle defined by the orientation of bores (relative to the normal). For one experimental study [48], nine impinging jet micro mixers were made which differ in these specifications. 

Reactor type Impinging-jet micro mixer-tube reactor Bore angles 45° 60° 90°... 

This process has the advantage that the materials are at all times handled in highly dilute solns, and that the mixer which uses a jet impingement principle has no moving parts. It has the disadvantage that the ingredients processed must in all cases be completely immiscible in the carrier, and it must also be possible to have a... 

Mixer 92 [M 92] Frontal-collision Impinging Jet Micro Mixer, Microjet Reactor ... 

Mixer 93 [M 93] Y-Type Collision Impinging Jet Micro Mixer... 

Figure 1.195 Photograph of the impinging jet micro mixer (left) and schematic of the design of the device (right) [53] (source IMM).

Table 1.8 List of parameters specifying the different impinging jet micro mixers diameter of the outlet boring d, the interspaces between the borings x and the angle a defined by the orientation of borings ([53] source IMM).

Figure 4.101 Experimental determination of the deviation of the total volume flow for the liquid-flow splitting unit alone and with six impinging-jet micro mixers attached. Concerning the latter, two cases were studied. First, the six best micro mixers were selected from 18 according to the minimal pressure drop deviation taking into account both outlet holes. Second, the same selection was done but relying on one hole only [141 ].

Apart from the impact and vibration tests dealt with previously, there are several other tests of friability, some of which appear in British Standards dealing with specific materials. Such tests include mixer tests, jet impingement tests, shear tests, tumbler tests and fluidized bed tests. Of these, the shear tests and tumbler tests are only considered worth mentioning here, with more details available from another BMHB publication54. 

As mentioned above, the Koppers-Totzek gasifier of powdery coal [4, 5], the Stagnation jet mixer [14] and the Trost jet mill [20] are practical examples of the successful application of impinging streams. Apart from these, very few industrial applications of impinging streams had been by the end of the last century, [9, 21], The following may account for the fact that the application of impinging streams has progressed so slowly ... 

The reaction system, the experiment procedure, and the analytical method used for the determination of micromixing in the TIJ mixer are the same as those described in the last section of this book but Mahajan et al. correlated their experimental data not with impinging velocity w() but with the jet Reynolds number Re. Also, the researchers employed the measure of increasing both the initial concentration CBo and the reaction temperature to raise the sensitivity of the procedure. The characteristic reaction time constant tK = 200 ms at 25 °C and CBo = 2.5 mM, while rR = 65 ms at 35 °C and CB0 = 4.7 mM, which can be used to bound the micromixing times, rM, no greater than them, respectively. 

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