Active and passive micromixers: A comprehensive review

•The present review (with 205 refs.) addresses the need for microdevices and presents the basic microfluidic equations.•The review describes the relevant numerical and experimental approaches.•Various types and designs of passive and active micromixers are discussed. The present review (with 205 refs.) addresses the need for microdevices, presents the basic microfluidic equations and describes the relevant numerical and experimental approaches. Various types and designs of passive and active micromixers are presented. In addition, the relevant effective dimensionless or dimensional parameters and the fabrication technology for different micromixer types are introduced. Different general configurations of lamination, obstacle, convergence-divergence and curved-channel are discussed for passive micromixers. The active micromixers are categorized and described as pressure field driven, acoustic field driven, magnetic field driven, electric field driven and thermal field driven.