In　the　present　work,　the　heat　transfer　and　solid　volume　fraction　distribution　characteristics　in　a　supercritical　water　(SCW)　fluidized　bed　with　immersed　tube　are　modeled　with　Two-Fluid　model　(TFM)　incorporated　with　the　Kinetic　Theory　of　Granular　Flow　(KTGF).　The　Gidaspow　drag　model　and　Gunn　heat　transfer　correlation　are　used　to　describe　the　interaction　and　heat　transfer　between　different　phases,　respectively.　A　comparison　between　SCW　and　gas-solid　fluidized　bed　was　conducted.　The　results　show　that　diameter　and　rising　velocity　of　bubbles　in　the　gas-solid　fluidized　bed　are　larger　than　that　in　the　SCW　fluidized　bed　when　the　corresponding　fluidization　numbers　in　both　systems　keep　the　same,　and　channeling　is　observed　only　in　SCW　fluidized　bed.　High　particle　concentration　is　always　accompanied　with　high　heat　transfer　coefficients　around　the　tube　in　the　gas-solid　fluidized　bed.　In　SCW　fluidized　bed,　however,　higher　particle　concentration　will　lead　to　lower　heat　transfer　coefficients　around　the　tube.　Smaller　fluctuations　of　solid　volume　fraction　and　heat　transfer　coefficients　are　also　observed　in　the　SCW　fluidized　bed　than　that　in　the　gas-solid　fluidized　bed.　In　addition,　the　influence　of　fast　fluid　inlet　velocity　on　solid　volume　fraction　and　heat　transfer　in　SCW　fluidized　beds　is　considered.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.