Gas-liquid-solid　packed　bed　reactors　or　trickle-bed　reactors　(TBRs)　have　been　widely　employed　in　various　industrial　applications　such　as　hydrocracking,　selective　hydrogenation　process　of　gas　oil,　wastewater　treatment　and　so　on.　Since　the　multiphase　flow　in　TBRs　is　complex,　uniform　liquid　distribution　can　hardly　be　obtained.　The　liquid　coverage　on　particles　at　various　locations　in　the　bed　affects　the　overall　reactor　performance.　In　this　work,　computational　fluid　dynamics　(CFD)　simulations　with　a　volume　of　fluid　(VOF)　model　were　employed　to　investigate　liquid　mal-distribution　at　the　micro-level　in　a　packed　bed　reactor.　In　this　study,　two　different　parameters　(the　local　liquid　coverage　(H-L)　and　local　liquid　holdup　(h(L)))　were　employed　to　describe　liquid　distribution　on　individual　particles.　The　liquid　distribution　at　different　particle　layers　was　investigated.　The　results　revealed　that　the　distributions　for　local　liquid　coverage　and　local　liquid　holdup　were　similar.　The　wetting　efficiency　and　the　liquid　residence　time　decreased　with　increasing　the　voidage.　In　a　packed　bed　with　cylindrical　particles,　the　capillary　effect　cannot　be　ignored　in　smaller　channels　formed　between　the　particles,　leading　to　higher　flow　resistance.　It　was　also　found　that　the　wetting　efficiency　and　liquid　film　thickness　increased　with　an　increase　in　the　liquid　velocity.　Both　wetting　efficiency　and　the　time　required　to　reach　steady　state　decreased　when　increasing　the　contact　angle.　The　flow　on　particle　surface　could　change　from　rivulet　to　film　as　the　liquid　density　decreased.　The　newly　unveiled　information　of　local　liquid　holdup　distribution　could　significantly　advance　the　understanding　of　gas-liquid　flow　hysteresis　inside　packed　beds,　based　on　which　the　reactor　performance　can　be　further　improved.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.