A method was proposed to enhance the single phase convective heat transfer. A stainless mesh cylinder was inserted into the tube concentrically to divide its cross section into an annular region and a central region. As the fluid passes the mesh cylinder

most of it enters the annular region because of resistance

modulating the flow field. Hot fluid in the annular region and cold fluid in the central region mix with each other more intensely through the mesh surface

enhancing the heat transfer. The heat transfer and pressure drop characteristics in the vertical upward flow with inserted mesh cylinder were investigated experimentally to validate the method. The mean and local Nusselt numbers and pressure drop data were obtained from the mesh cylinder tube and a smooth tube with water as the working fluid. The Reynolds numbers cover the range of 2392-20175 and the heat flux is in the range of 50.18-282.88 kW·m-2. The experimental results from the smooth tube are validated by using the well known equations in literature. Inserting a mesh cylinder increases the heat transfer and pressure drop considerably compared with the smooth tube. The heat transfer enhancement factors range from 1.21 to 1.84. In the entrance region or thermal developing region

the heat transfer enhancement factor is up to 2.64. Meanwhile

the pressure drop is 6.1-10.6 times larger than that of the smooth tube.