An example microfluidic mixer can include an inlet microfluidic channel portion and a fluid splitting channel portion including an overpass microfluidic channel to receive fluid from a first side of the inlet microfluidic channel portion and an underpass microfluidic channel to receive fluid from a second side of the inlet microfluidic channel portion, where the underpass microfluidic channel extends under the overpass microfluidic channel such that the channels overlap at their respective downstream ends. A fluid recombining channel portion is downstream of the fluid splitting portion and includes an angled recombining surface having an acute angle with respect to a direction of fluid flow, where the angled recombining surface is between the downstream ends of the overpass and underpass microfluidic channels. An outlet microfluidic channel portion is fluidly connected downstream from the fluid recombining channel portion.

An example microfluidic mixer can include an inlet microfluidic channel portion and a fluid splitting channel portion including an overpass microfluidic channel to receive fluid from a first side of the inlet microfluidic channel portion and an underpass microfluidic channel to receive fluid from a second side of the inlet microfluidic channel portion, where the underpass microfluidic channel extends under the overpass microfluidic channel such that the channels overlap at their respective downstream ends. A fluid recombining channel portion is downstream of the fluid splitting portion and includes an angled recombining surface having an acute angle with respect to a direction of fluid flow, where the angled recombining surface is between the downstream ends of the overpass and underpass microfluidic channels. An outlet microfluidic channel portion is fluidly connected downstream from the fluid recombining channel portion.

An example microfluidic mixer can include an inlet microfluidic channel portion and a fluid splitting channel portion including an overpass microfluidic channel to receive fluid from a first side of the inlet microfluidic channel portion and an underpass microfluidic channel to receive fluid from a second side of the inlet microfluidic channel portion, where the underpass microfluidic channel extends under the overpass microfluidic channel such that the channels overlap at their respective downstream ends. A fluid recombining channel portion is downstream of the fluid splitting portion and includes an angled recombining surface having an acute angle with respect to a direction of fluid flow, where the angled recombining surface is between the downstream ends of the overpass and underpass microfluidic channels. An outlet microfluidic channel portion is fluidly connected downstream from the fluid recombining channel portion.

A microdroplet/bubble-generating device comprising a slit and a row of a plurality of microflow paths is constructed, in such a manner that either a continuous phase or dispersion phase is supplied to the slit, and so that the end of the slit, the other supply port for the continuous phase or dispersion phase and the liquid recovery port are connected. The plurality of microflow paths each have a narrow part where the cross-sectional area of the flow channel is locally narrowed adjacent to or near the connection point between the slit and the microflow path. The continuous phase and dispersion phase that have met at the connection points flow into the narrow parts, and the dispersion phase is sheared at the narrow parts with the continuous phase flow as the driving force, forming droplets or gas bubbles of the dispersion phase. The product is recovered from the liquid recovery port.

A microdroplet/bubble-generating device comprising a slit and a row of a plurality of microflow paths is constructed, in such a manner that either a continuous phase or dispersion phase is supplied to the slit, and so that the end of the slit, the other supply port for the continuous phase or dispersion phase and the liquid recovery port are connected. The plurality of microflow paths each have a narrow part where the cross-sectional area of the flow channel is locally narrowed adjacent to or near the connection point between the slit and the microflow path. The continuous phase and dispersion phase that have met at the connection points flow into the narrow parts, and the dispersion phase is sheared at the narrow parts with the continuous phase flow as the driving force, forming droplets or gas bubbles of the dispersion phase. The product is recovered from the liquid recovery port.