Abstract: The heat transfer coefficient is relative low when the bulk temperature is above the pseudo-critical point due to the properties of vapor-like fluid. Numerical simulation on the heat transfer phe-nomena downstream of an obstacle in a vertical tube is carried out with commercial CFD code Fluent 6.1 us-ing adaptive grid. The results show that the RNG k-ε model with enhanced wall treatment can obtain reliable results; and the higher of the blockage ratio and the local temperature can achieve the better heat transfer en-hancement. The influence region and decay trend are also given.