This　paper　aims　to　study　the　influence　of　beams　depth　on　the　smoke　flow　characteristics　in　a　long-closed　channel　with　lateral　opening　and　multiple　ceiling　beams.　A　series　of　full-scale　experiments　and　numerical　simulations　with　different　fire　heat　release　rates　and　beam　depths　were　carried　out.　The　influence　of　beams　depth　on　the　smoke　spreading,　the　longitudinal　ceiling　temperature　distribution,　the　maximum　ceiling　excess　temperature,　and　the　smoke　mass　flow　along　the　channel　were　analyzed.　Results　show　that　the　existence　of　the　ceiling　beams　in　the　long　channel　with　closed　ends　makes　the　smoke　accumulate,　which　causes　the　time　of　the　ceiling　jet　stage　increase　with　the　increase　of　beams　depth.　The　longitudinal　ceiling　temperature　decays　faster　and　the　maximum　ceiling　temperature　rise　becomes　higher　with　the　increasing　depth　of　beams.　Additionally,　the　prediction　correlations　of　longitudinal　ceiling　temperature　distribution　and　the　maximum　ceiling　temperature　rise　in　the　long　channel　with　ceiling　beams　were　established.　Based　on　the　dimensional　analysis,　a　quantitative　correlation　to　predict　the　smoke　mass　flow　under　the　beam　is　proposed　considering　both　beam　parameters　(depth,　width,　and　the　distance　from　the　fire　source)　and　HRR.　The　smoke　mass　flow　decreases　with　increased　depth　of　beams　due　to　the　weakening　of　air　entrainment,　this　phenomenon　is　distinct　from　the　gradual　increase　of　smoke　mass　flow　observed　in　long　channels　with　open　sides.　This　study　is　anticipated　to　contribute　to　fire　prevention　and　the　understanding　of　the　smoke　flow　pattern　in　the　long-closed　channel　with　lateral　opening　and　ceiling　beams.　©　2025