Abstract: The heat transfer in the triangular ducts fitted with symmetric delta wings disturbance flow components is studied in pulsating flow using CFD software. The refrigerant is Water-SiO₂ nanofluid. The range of Reynolds number is 500~1 600. The results show that when the Reynolds number is 1 500 and amplitude is 0.75, there exists a critical frequency which is the flex spot between enhanced and weakened heat transfer with the pulsating conditions. The critical frequency is about 1 Hz. When the frequency is higher than 1 Hz, heat transfer is enhanced. However, when the frequency is lower than 1 Hz, which the heat transfer weakend. When the frequency is 10 Hz, the maximum heat transfer enhancement is 4%.When the frequency is 0.001 Hz, the maximum weakening of the heat transfer is 3%. The heat transfer mechanism is studied by using the field synergy principle. The smaller the field synergy angle is, the better the heat transfer effect is. The closer the distance from the delta wing is, the smaller the field synergy angle is. It can be observed that the average field synergy angle for Re=1 500, A_u=0.75 and f=10 is the smallest, and the enhanced heat transfer is the best.