Heat transfer and fluid flow performance in internally finned tube with blocked core-tube was numerically investigated with the realizable k-ε turbulence model and wall function method.The working fluid was air.The n...Heat transfer and fluid flow performance in internally finned tube with blocked core-tube was numerically investigated with the realizable k-ε turbulence model and wall function method.The working fluid was air.The numerical method was validated by comparing the calculated results with available experimental data.It was found that there existed an optimal value for the ratio of core-tube outside diameter to outer-tube inside diameter, and this optimal value decreased with the increase of air flow rate.The optimal ratio was about 0.5—0.625 in the range of studied parameters.Meanwhile under the condition of identical pressure, the optimal ratio was also about 0.44—0.56.The conclusion is useful for the design of this kind of internally finned tubes.展开更多
This paper performs experiment on heat transfer and pressure drop in different 3-D internally finned tubes, investigates the transition from critical zone to transition zone. Four expressions about the Reynolds criter...This paper performs experiment on heat transfer and pressure drop in different 3-D internally finned tubes, investigates the transition from critical zone to transition zone. Four expressions about the Reynolds criterion for transition, the largest Fanning friction factor, the Nusselt number and Fanning friction factor have been obtained respectively.展开更多
文摘Heat transfer and fluid flow performance in internally finned tube with blocked core-tube was numerically investigated with the realizable k-ε turbulence model and wall function method.The working fluid was air.The numerical method was validated by comparing the calculated results with available experimental data.It was found that there existed an optimal value for the ratio of core-tube outside diameter to outer-tube inside diameter, and this optimal value decreased with the increase of air flow rate.The optimal ratio was about 0.5—0.625 in the range of studied parameters.Meanwhile under the condition of identical pressure, the optimal ratio was also about 0.44—0.56.The conclusion is useful for the design of this kind of internally finned tubes.
文摘This paper performs experiment on heat transfer and pressure drop in different 3-D internally finned tubes, investigates the transition from critical zone to transition zone. Four expressions about the Reynolds criterion for transition, the largest Fanning friction factor, the Nusselt number and Fanning friction factor have been obtained respectively.
