About Phenomenology and Modeling of Dropwise Condensation

Abstract

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Optimization of Dropwise Condensation of Steam over Hybrid Hydrophobic–Hydrophilic Surfaces via Enhanced Statistically Based Heat Transfer Modelization

“…A similar correlation for the size distribution of small droplets was derived in [18]. However, numerical results from IBM simulations [11,21,22] show discrepancies between the computed small size distribution and the theoretical correlation of [17]. Since the Rose correlation [23] is known to overestimate the nucleation density, required by PBMs to define the threshold between small and large droplets, an updated model to include the effect of the coating thickness in the calculation of both the nucleation radius and the nucleation density was presented in [19,20] and integrated with the PBM of [17].…”

Effect of hydrophobic coating on optimization of dropwise condensation of steam on hybrid surfaces

“…( 8) is not reliable in the limit of droplet radius approaching the nucleation value. As proved in [12], this is due to the assumption that the renewal time τ * swe , associated to coalescence events, is a constant. Indeed, numerical results of [12] shows that the sweeping time linearly depends on the droplet radius.…”

“…As proved in [12], this is due to the assumption that the renewal time τ * swe , associated to coalescence events, is a constant. Indeed, numerical results of [12] shows that the sweeping time linearly depends on the droplet radius. Assuming τ * swe = τ * e r * and solving the droplet population balance, Eq.…”

“…However, it was numerically observed in [5,12] that Eq. ( 8) is not reliable in the limit of droplet radius approaching the nucleation value.…”

“…However, the size distribution of the smallest droplets with size down to the nucleation radius, whose growth is driven by condensation, has not been experimentally investigated due to the difficult access to the microscale. Even the theoretical correlation of [11] is not able to accurately predict the size distribution of small droplets [5,12], making the PBMs still not reliable for hybrid geometry optimization. Here, numerical analysis of DWC of steam over an hybrid surface such as the one investigated by [1] is conducted via Individual-Based Modelization (IBM).…”