Impacts of initial cooling rate on local frosting characteristics of horizontal cold plate surface with edge effect considered

Considering frosting process in applications usually starts along with cooling stage of the corresponding frosting components, a systematic study on the impacts of the initial cooling rate on the frosting characteristics in an edge zone of a cold plate is conducted. The experimental plate surface temperature, air temperature, relative humidity, and velocity were − 15.0 °C, 20.0 °C, 50%, and 1.5 m/s, respectively. It has been demonstrated that a single row of droplets near the plate edge was significantly larger than the remained droplets due to edge effect. The scope of edge effect on the frosting of cold plate was weakened as the initial cooling rate of cold plate increased. For cases with initial cooling stage, the ratio of the frozen stage period to the entire early frosting stage period increased as the initial cooling rate. Besides, compared to a frosting process without an initial cooling stage, frost thickness decreased by 5.5%, 20.7%, and 32.8% when the initial cooling rates were 1.5, 0.5, and 0.25 °C/s after a 1200-s frosting duration. The results can provide basic data for establishing accurate frosting models and bring insight into delaying frosting in practical applications.