Processes involving heat transfer from a humid air stream to a vertical plate, with simultaneous deposition of frost, are of great importance in a variety of refrigeration equipment. In this work, frost growth on a vertical plate in free convection has be

Bubble characteristics of steam–water two-phase upward flow were observed in a vertical pipe 155 mm in inner diameter. Experiments were conducted under volumetric flux conditions of JG<0.25 m/s and JL<0.6 m/s, and three different inlet boundary conditions to investigate the developing state of the flow. The radial distributions of flow structure were obtained by horizontally traversing optical dual void probes through the pipe. The spectra of bubble chord length and gas velocity were also obtained to study the characteristics of bubbles in detail. The flow reached a quasi-developed state within relatively short height to diameter aspect ratio of about H/D=4 compared to a small-diameter pipe flow. The PDF profiles of bubble chord length and gas velocity were able to approximate fairly well by model function using Gamma distribution and log-normal distribution, respectively.