The　behavior　of　different　viscous　models　on　the　non-premixed　swirling　diffusion　flame　and　local　extinction　effect　is　investigated　in　this　paper.　A　three　dimensional　numerical　simulation　is　conducted　on　Sydney　SMH1　flames　using　Wall-Modeled　LES　(WMLES)　model,　Kinetic　Energy　Transport　model　and　realizable　k-epsilon　model　coupled　with　laminar　flamelet　Model.　The　scatter　plots　of　temperature　are　analyzed　when　different　mixing　model　constants　Cvar　are　applied.　Scalar　dissipation　rate　theory　is　introduced　to　explain　the　influence　of　the　Cvar　on　the　local　extinction　prediction.　The　results　of　the　present　paper　show　that　model　constant　Cvar　has　a　significant　effect　on　accuracy　of　prediction　of　the　turbulent　model.　Among　the　three　viscous　models,　the　Kinetic　Energy　Transport　model　gives　the　best　prediction　oil　local　extinction　effect　at　the　main　recirculation　zone.　The　analytic　procedure　may　serve　as　a　reference　for　further　study　on　non-premixed　swirling　diffusion　flames.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.