Piezoelectric fans make use of the inverse piezoelectric effect to actuate the rotation of blades. These fans have the advantages of small size, low power consumption, and low noise output. In this study, we used the commercial computational fluid dynamics (CFD) software ANSYS CFD/Fluent to simulate a transient flow field in order to explore the impact of each column on the heat flow of a rectangular-channel piezoelectric fan installed inside each columnar radiator. The aim of this study was to find the best position for the piezoelectric fan cooling radiator. In the numerical simulation, the pressure radiator fan blade tip-to-tip distance (Lg), height of the piezoelectric fan center from the flow channel plate (Hw), fin row (n), radiator fin width (Wf), and the fin gap (G) were used for the vertical piezoelectric fan to obtain the Niu Saier number (Nu) and thermal resistance (Rth). Cyclical swings of the piezoelectric fan impede the uninterrupted flow of impact energy transfer on the boundary layer. At the tip of the blade actuation direction, the fluid reciprocating stroke, that is, the direction of the flow field, was pulled, and the front tip of the blade generated a vortex forming an entrained flow, but the hot and cold air were effectively mixed. The results showed that when the height of the center of the piezoelectric fan in relation to the flow channel plate was increased, the dissipation performance decreased comparatively. Furthermore, when a pressure fan was placed in front of the radiator, the height from the base center to the flow channel of the piezoelectric fan was reduced.