**Abstract**

Liquid cooling is an extremely successful process to remove excess heat generated, with the usual procedure of heat transfer using coolant in desktop PCs. In this regard, heat transfer with minimal size equipment can be achieved by the addition of nanosized solid particles to the base fluid. The hybrid nanofluid is synthesized by dispersing the synthesized mono nanofluid in a volume fraction of 0.2 iron oxide with 0.8 fractions of graphene nanofluid to form a graphene/iron oxide combination. These nanoparticles increase the heat transfer coefficient as they have high thermal conductivity when compared to conventional heat transfer fluids like water or ethylene glycol. Stability is increased and sedimentation is reduced because of the large surface area of a nanoparticle. FLUENT, the most widely used computational fluid dynamics (CFD) software package, based on the finite volume method, and is used to run the thermal simulations for estimating the base temperature of the heat sink. The scope of this chapter is to find the base temperature of the heat sink using simulations. The experimentally measured base temperature is 310.01 K and in the simulation, it is 310.81 K for the flow rate of 0.75LPM. All the simulated surface temperatures are compared with experimentally determined temperatures for simulation validation.

**Keywords:** microchannel, nanocoolant, base temperature, CFD
