This paper presents the experimental and numerical results of the heat-transfer characteristics of a water-cooled heat sink with different outlet layouts. An experimental apparatus was set up to validate the numerical results. The coolant flowed vertically into the heat sinks from the center of their top wall. Heat sinks A and B each had only one outlet

located at one corner or at the center of the edge

respectively. For heat sinks C and D

four outlets were set at each corner or at the center of each edge

respectively. The numerical simulation results were validated by comparing them with experimental data. The results show that the relative error of the numerical simulation is less than 7%. The heat-transfer characteristic of the heat sink depends on four parameters: the velocity distribution

pressure loss

comprehensive effect

and the Nusselt (Nu) number

which is the ratio of convective to conductive heat transfer. The numerical results indicate that the Nu numbers of the heat sinks with four outlets are lower than those with one outlet. However

the flow resistance is lower and the comprehensive coefficient is higher. The comprehensive coefficient of four outlets is 50% higher than that of the heat sink with one outlet. The four-outlet heat sink has better heat transfer and flow effects.