A heat sink removes heat from an electronic device and comprises a base, a lid. An inner ring of first fins extend radially outwardly first length from an inner circle and extend axially a first height from the top surface of the base, and an outer ring of second fins extend radially inwardly a second length from an outer periphery and extend axially a second height from the top surface of the base. A confining plate extends radially above the fins and is spaced below the bottom surface of the lid whereby coolant fluid flows from an inlet opening of the lid through the center opening of the confining plate and radially outwardly through the fins and upward around the outer edge of the confining plate and into the space above the confining plate to an outlet opening. A nozzle having a throat is disposed above the lid and extends below the lid to the confining plate. A flow diverter extends upwardly from the top surface of the base and into and through the throat of the nozzle.