Heat transfer and fluid flow performance in internally finned tube with blocked coretube was numerically investigated with the realizable k-ε turbulence model and wall function methodThe working fluid was airThe numerical method was validated by comparing the calculated results with available experimental dataIt was found that there existed an optimal value for the ratio of coretube outside diameter to outertube inside diameter
and this optimal value decreased with the increase of air flow rateThe optimal ratio was about 0.5—0.625 in the range of studied parametersMeanwhile under the condition of identical pressure
the optimal ratio was also about 0.44—0.56The conclusion is useful for the design of this kind of internally finned tubes.