Flow　boiling　in　microchannel　is　a　potential　technology　for　the　thermal　management　of　high-heat　flux　microelectronic　devices.　A　microchannel　with　triangular　cavities　(TC)　is　proposed　for　flow　boiling　enhancement　in　this　work.　Flow　boiling　experiments　with　high　speed　flow　visualization　are　performed　in　the　TC　microchannel　and　the　conventional　rectangular　(R)　microchannel　using　pure　acetone　liquid　as　the　working　fluid.　The　bubble　characteristics,　heat　transfer,　pressure　drop　and　wall　temperature　performances　for　the　TC　microchannel　are　investigated　and　compared　with　that　for　the　R　microchannel　at　inlet　temperature　of　29　degrees　C　and　mass　flux　ranging　from　83　to　442　kg/m(2)　s.　Moreover,　the　effects　of　mass　flux　and　heat　flux　on　the　flow　boiling　performance　are　also　studied.　The　experiment　results　show　that　the　TC　microchannel　presents　significant　enhancement　of　heat　transfer,　obvious　reduction　of　pressure　drop,　more　stable　and　uniform　wall　temperature　compared　to　the　R　microchannel.　The　triangular　cavity　configuration　causes　the　enlargement　of　heat　transfer　area,　the　formation　of　developing　liquid　film,　the　increase　of　nucleation　density　and　bubble　departure.　The　novel　micro　heat　sink　obtains　a　high　heat　transfer　coefficient　with　the　increment　as　high　as　9.88　and　1.55　times　accompanied　by　a　low　pressure　drop　with　50.3%　and　12.8%　reduction　compared　to　the　R　microchannel　at　G　=　83　and　442　kg/m(2)　s,　respectively,　which　makes　it　more　promising　and　efficient　for　microelectronic　cooling.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.