Surface wave dynamics of vertical falling films under monochromatic-frequency flowrate-forcing perturbations is computed by the direct simulation of Navier–Stokes equations using the Volume of Fluid (VOF) method to track free surfaces and the Continuum Surface Force (CSF) model to account for dynamic boundary conditions at free surfaces. The numerical VOF–CSF model is completely formulated, and...

Horizontal-tube, falling-film heat exchangers are used in many air-conditioning and refrigeration systems. Depending on the geometry, flow rate and fluid properties, when a liquid film falls over a series of horizontal tubes several distinct flow patterns can be manifested: the droplet mode, the jet mode, and the sheet mode. A thermodynamic analysis is undertaken to predict the transitions betw...

Capacity and efficiency of any refrigerating system diminish rapidly as the difference between the evaporating and condensing temperature is increased by a reduction in the evaporator temperature. The single stage vapour compression refrigeration system using various refrigerants are limited to an evaporator temperature of -40 0C. Below temperature of -40 0C the either cascade refrigeration sys...