engleski

Effects of surface deposition and droplet injection on film cooling

In present research, the influence of the particle dispersion into the continuous phase was analysed by treating droplets as sources of mass, momentum and energy in the gas flow field. The interaction between the water droplets and the mainstream plays an important in role in the outcome results. To develop the effective modelling of both continuous gas and dispersed phases, the accurate prediction of two-phase flows was investigated by using discrete phase model (DPM). The goal of the present study is to contribute to improve the knowledge about heat transfer in the near-wall region by mist cooling. During the study, the local wall temperature distributions and film cooling effectiveness were obtained by numerical simulations. The results indicated that 2% mist injection can enhance the film cooling performance significantly. Since different sizes of deposition present the effect of evaporation cooling on the downstream wall, different heights of surface deposition were also considered by using the models both with and without droplet injection. For no mist injection, smaller deposition provides a lower wall temperature and a better cooling performance. With 2% mist injection, evaporation of water droplets improves the film cooling effectiveness, and the higher deposition causes lateral and downstream spread of water droplets.

film cooling; injection; mist cooling; deposition; water droplet; thermal barrier coating

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