Because of the current major stakes in energy saving and environmental matters, optimizing heat transfer and mixing performances is a major objective in many industrial fields such as chemistry or food industry. This improvement is required for better yield control, as well as to increase the efficiency of continuous production processes and ensure better product quality. As a result, many studies aim to better understand and improve the rate of heat and mass transfer in industrial devices such as reactors or multifunctional heat exchangers. These transfer optimization studies on systems are mainly based on the improvement of the convective transfer, which is obtained by modifying the flow structuring. Two types of improvement techniques can be carried out. The active ones, in which the flow is modified by adding an external energy source, and the passive ones, in which only the modified geometry influences heat and mass transfer. We are interested in the second technique. Several previously published studies have shown that applying macro-deformations to the walls of an annular tube flow configuration can significantly improve heat transfer and mixing in laminar flow regime, by comparing with the smooth annular tube reference configuration [1-4]. Within this framework, two main parietal deformation are numerically studied and presented in the present communication. The first one is based on the modification of the cross-section shape which gradually varies from circular to elliptic in alternate directions. The second one is based on a constant elliptical cross-section which axis orientation varies helically in the flow direction. It allows to create a swirl movement of the tube’s wall. This numerical study aims at the fine analysis of the mechanisms that allow to improve both the heat transfer and the mixing performances in laminar flow regime. Governing conservation equations for an incompressible fluid in anisothermal steady flow are thus solved using a finite-volume based CFD (Computational Fluid Dynamics) code. The Reynolds numbers range considered extends from 200 to 1000. The global thermo-hydraulic performances are evaluated by a performance factor: the PEC (Performance Evaluation Criterion) which allows to compare simultaneously the gain in terms of heat transfer related to the evolution of the pumping power. The quality of the mixture is characterized by Poincare sections and mixing rates. For some geometrical configurations the results show that an increase in PEC and a more uniform distribution of the particles at the outlet compared to the reference configuration (smooth annular tube). A detailed analysis of the velocity, helicity and temperature fields allows us to better understand the physical mechanisms involved and their variation as a function of geometric parameters and the Reynolds number.