Measurements of the Heat and Mass Transfer Parameters Characterizing Conical Graupel Growth

Publisher Website
Google Scholar
Abstract
Rigidly suspended conical graupel were grown in a wind tunnel, starting from 1-mm hexagonal plates, with liquid water content varied from 0.5 to 3.0 g m−1, velocity from 1.1 to 3.0 m s−1, ambient temperature from −4.4 to −20.9°C, cloud droplet median volume radius from 12 to 21 μm, and ambient pressure from 100 to 60 kPa. Growth conditions were chosen to simulate natural conditions in which conical graupel grow and serve as embryos for hail. Final graupel diameters ranged from 1.5 to 6 mm, with Reynolds numbers between 300 and 1500. Measurements of the mass, volume, growth height, geometric shape, and surface temperature with time were used to calculate the Nusselt and Sherwood numbers (representing the convective heat and mass transfers), bulk collection efficiency, and accretion density. The bulk collection efficiency and Nusselt number were parameterized in terms of the Stokes parameter and Reynolds number, respectively. The density and cone angle were parameterized in terms of the relative gr... Abstract Rigidly suspended conical graupel were grown in a wind tunnel, starting from 1-mm hexagonal plates, with liquid water content varied from 0.5 to 3.0 g m−1, velocity from 1.1 to 3.0 m s−1, ambient temperature from −4.4 to −20.9°C, cloud droplet median volume radius from 12 to 21 μm, and ambient pressure from 100 to 60 kPa. Growth conditions were chosen to simulate natural conditions in which conical graupel grow and serve as embryos for hail. Final graupel diameters ranged from 1.5 to 6 mm, with Reynolds numbers between 300 and 1500. Measurements of the mass, volume, growth height, geometric shape, and surface temperature with time were used to calculate the Nusselt and Sherwood numbers (representing the convective heat and mass transfers), bulk collection efficiency, and accretion density. The bulk collection efficiency and Nusselt number were parameterized in terms of the Stokes parameter and Reynolds number, respectively. The density and cone angle were parameterized in terms of the relative gr...

This publication has 0 references indexed in Scilit: