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In this study, a numerical simulation is performed to explore oscillatory natural convection in a square enclosure with a phase change material (PCM) suspension using the implicit finite difference method. The following parameters are considered: aspect ratio of the physical model = 1; ratio of the buoyancies caused by temperature and concentration gradients = 1; Rayleigh number = 103-106; initial mass fraction (or concentration) of PCM particles = 0–0.1; Stefan number = 0.005–0.1; and subcooling factor = 0–1.0. The results show that high Rayleigh numbers can easily cause oscillations in the flow field and temperature distribution. However, even under low Rayleigh number conditions, when the initial mass fraction or subcooling is increased or the Stefan number is decreased, oscillations occur. • Heat transfer in an enclosure with PCM suspension was numerically investigated. • Oscillatory natural convection phenomena are found. • High Rayleigh numbers can easily cause the oscillations in the flow and temperature. • High initial mass fraction or subcooling can cause, even under low Rayleigh numbers. • Low Stefan numbers cause too, under low Rayleigh numbers. [ABSTRACT FROM AUTHOR]

Abstract: Using the Buckingham Pi theorem, this study derives dimensionless correlations to characterize the heat transfer performance of the corrugated channel in a plate heat exchanger. The experimental data are substituted into these correlations to identify the flow characteristics and channel geometry parameters with the most significant influence on the heat transfer performance. Simplified correlations by omitting the factors with less influence are then obtained. The results show that Nu x is affected primarily by Re, R/D h, x/D h, and β. Neglecting the minor effect of factors on Nu x, it is shown that Nu m is determined primarily by Re, R/D h and β. [Copyright &y& Elsevier]