The present study explores the parametric investigation of a heat sink filled with composite of pure phase change material (PCM), nanocomposite phase change material (NCPCM), metal-foam (MF) by employing the numerical approach for effective passive thermal management of electronics. The combinations of heat sink are varied by filling PCM, NCPCM, MF+PCM and NCPCM+MF. Different parameters such as MF materials, porosities, pore densities (PPI-pores per inch), volume fractions of nanoparticles in NCPCM, power levels and combination of MF+NCPCM by varying different porosities and nanoparticles volume fractions. Copper (Cu) nanoparticles of 1%, 3% and 5% volume fraction were dispersed in RT-35HC, used as a PCM, and copper, aluminium (Al) and nickel (Ni) MFs were embedded inside the heat sink. Transient simulations with conjugate heat transfer and melting/solidification schemes were formulated using finite-volume-method (FVM). The thermal performance and melting process of the NCPCM filled heat sink were evaluated through melting time, heat storage capacity, heat storage density, rate of heat transfer and rate of heat transfer density. The results showed that with the addition of Cu nanoparticles and MF, the rate of heat transfer was increased and melting time was reduced. The melting time was reduced by −1.25%, −1.87% and −2.34%; and rate of heat storage is enhanced by 1.35%, 0.76%, and 0.19% with the addition of 1%, 3% and 5% volume fraction of Cu nanoparticles, respectively. The composite of MF+NCPCM showed the lower heat sink temperature and higher liquid-fraction were obtained. The latent-heating phase duration was decreased with the increase of Cu nanoparticles volume fraction. Additionally, the lower reduction in melting time of −18.10% and higher rate of heat transfer of 8.12% were obtained with 1% Cu nanoparticles, 95% porosity and 10 PPI Cu MF based heat sink.