Complex microchannel geometries

More complex geometries have been developed [40] and the influence of the geometrical structure has been examined. Although straight-through microchannel emulsification has been developed [39,41], the production rates are still low compared to those obtained with standard emulsification methods. However, the very high monodispersity makes this emulsification process very suitable for some specific fechnological applicafions such as polymeric microsphere synfhesis [42,43], microencapsulation [44], sol-gel chemistry, and electro-optical materials. 

Often complex geometries are used for the design of MSR. An example is the channel structure developed by the chemical company LONZA Ltd., Switzerland [16], where mixing elements are integrated in the microchannels (Figure 5.11). In these cases, the estimation of the active heat transfer surface area and the heat transfer coefficients are hardly possible. Therefore, the introduction of an overall volumetric heat transfer coefficient (U ) is useful. 

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