Liquid-based heat exchanger

A liquid cooled thermal heat sink device 200 comprising a housing having a fluid inlet 220 and a fluid outlet (230, figure 13), the fluid inlet being in fluid communication with a plenum chamber 230, the plenum chamber comprising a jet orifice plate 240 which defines a plurality of jet orifices 241 through which a pressurised liquid can operably exit the plenum chamber and contact a thermal surface 250, the device further defining surfaces of at least one exit channel 255, the at least one exit channel being configured to deliver fluid exiting the jet orifices to the fluid outlet. Therefore preferably the plenum chamber forms a pressurized chamber and the plurality of jet orifices provide an exit for the pressurised liquid to exit and impinge on the thermal surface (which may comprise an integrated heat spread IHS, and be formed from a thermal interface material TIM) whereby they effect a cooling of the thermal surface, the heated liquid being transferred through the exit channel to dissipate heat away from the thermal surface. Preferably a sealing skirt 265, such as an o-ring, is included.