This　second　part　of　a　three-part　study　concerns　pressure　drop　of　laminar　flow　in　microchannel　heat　sinks　with　water　and　silicon　used　as　fluid　and　solid　for　the　computational　domain.　In　the　rectangular　microchannel　with　width　of　0.1　mm　and　depth　of　0.2　mm,　the　repeating　aligned　or　offset　fan-shaped　ribs　are　mounted　to　the　channel　sidewalls.　To　examine　the　influence　of　fan-shaped　rib＇s　geometry　on　thermal　and　hydraulic　characteristics　of　laminar　flow,　three　non-dimensional　variables,　representing　the　width　(0.05-0.4　mm),　height　(0.005-0.025　mm)　and　spacing　(0.2-5　mm)　of　fan-shaped　ribs　are　designed.　The　present　study　firstly　presents　the　pressure　distributions　in　microchannels　to　analyze　the　local　hydraulic　characteristics,　and　then　examines　the　local　pressure　and　friction　factor　along　the　flow　direction　for　different　geometry　of　fan-shaped　ribs.　Results　show　that　the　fan-shaped　ribs　can　lead　to　large　increase　of　local　pressure　in　comparison　with　the　smooth　microchannel,　especially　for　the　aligned　fan-shaped　ribs.　Further,　the　effect　of　fan-shaped　ribs＇　geometry　on　the　average　friction　factor　has　been　investigated.　Results　show　that　with　the　increase　of　fan-shaped　ribs＇　width,　the　friction　factor　ratio　of　the　studied　microchannels　to　the　smooth　one　firstly　decreases　and　then　increases.　The　increase　of　fan-shaped　ribs＇　height　and　decrease　of　ribs＇　spacing　can　lead　to　the　extreme　increase　of　average　friction　factor,　especially　for　the　microchannels　with　aligned　fan-shaped　ribs.　For　Reynolds　number　ranging　from　187　to　715,　the　microchannels　with　aligned　fan-shaped　ribs　show　the　average　friction　factor　1.1-8.28　times　larger　than　the　smooth　one,　while　those　with　offset　fan-shaped　ribs　show　1.22-6.27　times　higher.　New　pressure　drop　correlations　for　such　microchannel　heat　sinks　are　developed,　which　fit　the　present　data　with　a　mean　absolute　error　of　13.2%　for　the　ones　with　aligned　fan-shaped　ribs　and　13.5%　for　the　ones　with　offset　fan-shaped　ribs.　Crown　Copyright　(C)　2016　Published　by　Elsevier　Ltd.　All　rights　reserved.