## 1 Introduction
### Literature Review
#### 1.2.1 Surface Roughness and General Porosity  
Early and foundational efforts in boiling enhancement explored the impact of surface roughness and general porous media. Surface roughening has been investigated for its ability to create more nucleation sites and improve liquid wicking. [PERSON] et al. [18] systematically varied surface roughness (Ra) on copper from 0.041 \(\upmu\)m to 2.36 \(\upmu\)m in saturated water, observing a strong dependence and significant enhancement of CHF with increasing roughness. Their roughest surface (Ra = 2.36 \(\upmu\)m) achieved a CHF of 1625 kW/m\({}^{2}\), approximately twice that of the smoothest surface, attributed to enhanced capillary wicking and improved liquid supply to dry spots. Similarly, [PERSON] et al. [19] explored sandblasting as a scalable surface engineering technique on silicon surfaces, varying the abrasive sizes (25, 50, 100, and 150 \(\upmu\)m of Al\({}_{2}\)O\({}_{3}\)). They found that increasing the surface roughness led to an increased volumetric wicking rate, with their roughest surfaces achieving up to a 434.3% improvement in HTC and a 192.6% improvement in CHF compared to a smooth silicon surface. [PERSON] et al. [20] utilized laser treatment to create precise surface modifications, specifically micro-fins (grooves) and surface roughness. Their experiments on distilled water and ethyl alcohol revealed that these \"macro\" and \"micro\" scale modifications significantly enhanced heat transfer, especially at small superheats. Samples with 0.4 mm high micro-fins showed a maximal heat flux dissipation over three timeshigher for water and two times higher for ethanol compared to samples with smaller (0.2 mm high) micro-fins.  
Beyond basic roughness, the bulk properties of porous media have been studied. [PERSON] et al. [21] numerically investigated the influence of porous media structural parameters, such as porosity, pore density, height, thermal conductivity, and wettability. They found that higher porosity (57.5% to 98.0%) could increase the CHF by an average of 3.75 times and the HTC by an average of 3.84 times compared to a plain surface. [PERSON] et al. [22], using porous media made of copper beads (free-moving particles) in packed structures, observed a 126% increase in HTC compared to flat plates, emphasizing the importance of particle size, weight, and arrangement. [PERSON] et al. [23] investigated the effect of sintered porous copper structure thickness, presenting pool-boiling curves for four different thicknesses, both with and without a graphene coating. Their study highlighted enhanced heat transfer due to increased wetted areas, nucleation sites, and improved thermal conductivity. Thinner, porous structures achieved optimal performance, with up to a 161% enhancement compared to bare copper, which was attributed to lower vapor resistance and more efficient liquid supply compared to thicker samples. [PERSON] et al. [24] investigated pool boiling of HFE-7100 on porous copper foam heating surfaces, finding that the foam thickness significantly impacts both the bubble dynamics and HTC. They reported that a 1 mm-thick copper foam sample yielded the highest HTC, a 145% improvement over a smooth surface. This enhancement was attributed to an increased liquid supply via capillary forces as the foam thickness decreased. Their study further revealed that thicker foams perform better at low heat fluxes, while thinner foams excel at high heat fluxes. Below 50 kW/m\({}^{2}\), an increased surface wetted area enhances natural convection. However, at higher heat fluxes, vapor bubbles trapped within the foam structures lead to unstable boiling patterns. Consequently, thinner foams reduce vapor trapping, resulting in an improved HTC and reduced dry-out heat flux.