The analysis of heat and mass transfer process has important guiding significance for the performance improvement of heat and mass transfer equipment. Through the analysis of the thermal resistance in the boundary layer

the author explores the development of the convective thermal resistance and thermal conduction thermal resistance in the laminar flow of the pipeline in the boundary layer

and establishes a mechanism model(R-P model)that conforms to the macroscopic characterization. The thermal resistance distribution law under the condition of Re and Pr

explored the internal mechanism of laminar flow enhanced heat transfer in the tube

and guided the optimal design of the flow-around structure. The results show that the heat conduction is absolutely dominant in the inlet stage

and the proportion of convection gradually increases after the full development. The mechanism of Re and Pr affecting heat transfer is different. When Re increases

the heat transfer must be strengthened. When Pr increases

it only increases the proportion of convection

and in the range of(Pr1.8)

thermal resistance always plays a major role. At the same time

it was found that adding a turbulent flow structure to the laminar flow in the pipeline would reduce the heat transfer effect.