Radial　graded　porous　volumetric　solar　receiver　is　designed　to　match　the　non-uniform　solar　flux　distribution.　Based　on　the　computed　tomography　and　image-processing　techniques,　uniform　and　radial　graded　porous　volumetric　solar　receivers　are　reconstructed.　The　3D　printing　technique　and　suitable　post　processing　are　implemented　to　fabricate　complex　porous　samples　using　super-alloy　Inconel　718　as　material.　Both　experimental　and　numerical　studies　are　conducted　to　investigate　the　fluid　flow　and　heat　transfer　processes　in　porous　volumetric　solar　receivers.　The　results　present　that　the　3D　printed　porous　samples　are　suitable　for　solar　thermal　energy　absorption　and　high　temperature　utilization.　As　for　uniform　porous　receivers,　porous　media　with　small　pore　diameter　has　larger　thermal　efficiency　because　of　enhanced　convective　heat　transfer.　Compared　with　the　uniform　porous　receiver　with　highest　thermal　efficiency,　the　radial　graded　porous　volumetric　solar　receiver　with　large　pore　diameter　inside　could　further　relatively　increase　the　thermal　efficiency　by　4.1%　while　relatively　decreases　the　flow　resistance　by　8.6%.　The　reasonable　distribution　of　pore　diameter　of　porous　media　could　regulate　the　mass　flow　distribution　and　direct　more　air　to　the　high　heat　flux　region.　Moreover,　local　overheating　phenomenon　is　observed　in　the　uniform　porous　receiver　using　air　as　heat　transfer　fluid.　By　applying　the　coupled　optimization　method,　an　optimum　pore　diameter　distribution　is　determined　for　the　radial　graded　porous　volumetric　solar　receiver.　©　2020　Elsevier　Ltd