An oval-tube structure is used as the new generation aero-engine recuperator, which has a wide range of application prospects in aerospace, marine and other important industrial fields. The heat transfer performance of this structure directly determines the energy efficiency of the aero engine. However, the enhanced heat transfer mechanism of oval-tube recuperator is not clear due to the lack of internal flow field information. Based on the standard k-ε model, shell-side heat transfer and resistance performance are conducted by using commercial CFD software FLUENT. The influences of structural parameters and tube arrangement on heat transfer and resistance performance are further studied. Then the mechanism on heat transfer augmentation is discussed according to the fluid flow characteristics and the field coordination principle. The results show that the standard k-ε and periodicity model is feasible and accurate to simulate the fluid flow on shell side of oval-tube recuperator. The heat transfer and resistance performance increase with the ratio of major and minor axes and longitudinal spacing of oval-tube. With the increase of horizontal and longitudinal spacing of oval-tube, the performance increases at first and then decreases. The maximum velocity appears at the minor axis, and the minimum value of fluid temperature, velocity and pressure appears at the major axis. The amplitude of field synergy angle is small in the inlet section, but the fluctuation amplitude in the recuperator is large.
Keywords oval tube, recuperator, heat transfer, numerical simulation, computational fluid dynamics(CFD)