Correlations for transient thermal convection of water near its densityinversion point in a square enclosure heated from below

Transient natural convection in water-filled square enclosures with the bottom wall heated at 8°C and the top wall cooled at 0°C is studied numerically for different cavity widths, in the hypothesis of temperature-dependent physical properties, assuming that the initial temperature of water is 0°C. A computational code based on the SIMPLE-C algorithm is used to solve the system of the mass, momentum and energy transfer governing equations. The propagation of convective motion from the bottom to the top of the enclosure is investigated up to the achievement of the steady-state regime. A number of dimensionless correlations are developed for the calculations of the heat transfer rates at the heated and cooled walls during time, as well as at steady-state.