BACKGROUNDA　passive　planar　micromixer　with　dislocation　sub-channels,　based　on　the　principle　of　planar　asymmetric　split　and　recombination,　has　been　proposed　for　its　effective　mixing.　Both　numerical　simulations　and　experiments　were　used　to　design　and　investigate　the　effect　of　parameters　and　flowing　feature　on　mixing　with　Reynolds　numbers　ranging　from　1　to　100.　The　mixing　index,　which　is　used　as　the　measurement　criteria,　is　dependent　upon　Reynolds　number　and　geometrical　parameters.　RESULTSThrough　the　results　of　numerical　and　experimental　simulation,　it　is　evident　that　the　arrangement　of　dislocation　sub-channel　structure　will　result　in　better　fluid　mixing　owing　to　the　combination　of　the　unbalanced　inertial　collisions,　the　multidirectional　vortices　and　the　collision-induced　flow　in　mixing　cavities　between　every　two-looped　structure.　The　effect　of　transverse　Dean　Vortices　in　the　vertical　plane　and　expansion　vortices　in　the　horizontal　plane　is　beneficial　for　the　increased　interfacial　area　between　two　species　and　promoting　mixing.　The　increased　width　ratio,　w(3)/w(4),　provided　by　the　dislocation　structures,　results　in　better　mixing　performance,　but　also　causes　a　higher　pressure　drop.　Experimental　results　allow　better　validation　of　the　mixing　efficiency　of　this　micromixer.　CONCLUSIONThe　best　mixing　performance　was　achieved　with　width　ratio　of　the　dislocation　sub-channels　at　w(3)/w(4)=1.0　and　Reynolds　numbers　less　than　80.　To　consider　the　mixing　effect　and　the　packaging　requirements　of　the　experiment,　the　mixing　index　of　the　micromixer　with　a　dislocation　sub-channel　can　reach　86%.　(c)　2013　Society　of　Chemical　Industry