Thermal control of electronic components is a continuously emerging problem as power loads keep increasing. In this study effects of vortex promoter on cooling 18 flash-mounted electronic components, which have constant heat fluxes, inside a rectangular channel, consisting of one open and three blocked sides were investigated experimentally and numerically by using a single jet flow. Copper blocks were used as electronic components. Flow velocities at the inlet to the channel were measured by using a Laser Doppler Anemometer (LDA) system. Temperature measurements were performed by using thermocouples. In order to improve heat transfer from electronic components, effects of vortex promoter parameters ( length, location, number, and angular position) on heat transfer were investigated for a Reynolds number of Re = 8000, heat flux q" = 1000 W/m(2), and the ratio of the jet-to-plate distance to hydraulic diameter of a nozzle H/D-h = 6. The local and mean Nu numbers were determined as a function of the ratio of distance between vortex promoter and jet inlet to hydraulic diameter of jet inlet (N/D-h) in the range 0.55-5.0, the ratio of vortex promoter's length to channel height (K/H) in the range 0.5-0.9, the ratio of the distance between two vortex promoters to channel height (W/H) in the range 0.5- 1.5, and the angle of vortex promoter. in the range (-5(o)-(+45(o)).The low-Reynolds number k- epsilon turbulence model was used in numerical investigations. The heat transfer rate for N/D-h = 0.7- 5.0 improved when the vortex promoter approached the jet entrance. It was observed that heat transfer is sensitive to the location, length, and angular position of the vortex promoter.