A coupled finite volume & discrete element method to examine particulate foulant transport in metal foam heat exchangers

The exorbitant costs associated with particulate fouling necessitates the need to formulate advanced methods to comprehend mass transport and fouling in heat exchangers. A coupled finite volume and discrete element method is developed to investigate the mechanisms that govern particle-laden gas flows and particulate fouling in idealized porous metal foam heat exchangers. This meticulous examination will take great precedence in addressing the negative impact particulate fouling has in the industry. The numerical method will permit engineers to better optimize porous metal foams for applications such as air-cooled heat aluminium heat exchangers. The robustness of this numerical method is validated against the original and modified Darcy-Forchheimer analytical equations through a novel modified porosity theory. Good agreement is obtained between the numerical and analytical results. It is shown that both 2D and 3D heat exchanger configurations of identical porosities with different geometric profiles have shown similar deposition fraction and pressure drop magnitudes albeit having a slightly different fouling layer distribution. This is attributable to the particle properties and the variation between the 2D and 3D inlet injection plane surface area. It is found that the commencement of sandstone and sawdust deposition in a 6-pore configuration differs by 0.57 s, whereas a three pore configuration completely nullifies particulate fouling irrespective of foulant type. A staggered row configuration has shown significant reduction in pressure drop as compared to the 6-pore heat exchanger configuration. For the case of sandstone particles, the optimum heat exchanger geometry exhibits 78% less pressure drop and 100% less deposition fraction compared with the original 6-pore configuration.