Vapor Solidification of Saturated Air in Two-Dimensional Stagnation Flow

Abstract

This study aims to investigate the stagnation-ow solidi cation of vapor from saturated air. Saturated air with strain rate a impinges on a at plate and, thus, condensation occurs and an icy layer forms on the plate because the plate temperature is below the freezing temperature of water. The ice surface was modeled as an accelerated at plate that moves toward the impinging uid. The unsteady Navier-Stokes equations were subjected to a similarity transformation to obtain a single ordinary di erential equation for velocity distribution. Two methods of solution were used for the energy equation: a nitedi erence numerical technique and a numerical solution of a similarity equation. These two results were compared to determine the superior accuracy. First, freezing time increases as the far-eld temperature decreases from 0 C and, then, rapidly approaches zero as the fareld temperature approaches 0 C. Despite the expectation that condensation would begin at the substrate in a physical experiment, here, the size of the cell next to the substrate controls the time at which condensation begins. It was found that the maximum time before freezing began at an air temperature of about 5 C for 0.1 and 0.2 mm sizes. The ultimate frozen thickness for two saturated air temperatures was presented.

Thermophoresis and Brownian motion effects of nanoparticles on Radiative heat transfer in Hiemenz flow: Using Spectral Method

“…(15) The linearized system in Eqs. (13) with boundary conditions ( 14) is solved using the Chebyshev Spectral Collocation method [33][34][35]. The physical domain from 0 to 1 is rst converted into the nite domain of 0 to L. The value of L is chosen su ciently large.…”

“…Tayebi et al [33] analyzed free convection heat transfer in an annulus between confocal elliptic cylinders lled with CNT-water nano uid and found that the average Nusselt number was an increasing function of modi ed Rayleigh numbers. Abbasi and Ghayeni [34] studied saturated air water freezing in two-dimensional stagnation ow on a at plate. According to their study, below the start temperature of freezing, 10 C drop in substrate temperature causes a large increase in the ultimate thickness of the ice at fareld air temperature of 5 C, while it slightly increases the ultimate thickness of the ice at the air temperature of 20 C. Rana et al [35] considered hydrothermal characteristics of nano uid using KKL model with Brownian motion and recommended nano-uids as a better coolant than the base uid.…”