| Droplet evaporation has important research significance as the basic principle of liquid fuel combustion and spray cooling. The research of droplet evaporation under directional intense radiation is insufficient in related field at present. The problem of droplet evaporation under infrared laser heating is studied based on the experimental study and numerical simulation in this paper.An experimental apparatus for single droplet evaporation under infrared radiation is designed. Quartz fibre is used to hang the droplet. The process is monitored by an electronic magnifier and an infrared thermal camera, and image analysis software is used for data processing. Changes of size and temperature of droplet evaporation process are recorded completely. Droplet evaporation characteristics of different laser wavelength, different laser power and different initial droplet diameter are studied.Based on Monte Carlo method, the entirety absorption and the internal absorption distribution characteristics of spherical droplet with different size under different wavelengths and different distribution modes are calculated and analyzed. Apparent emissivity of the isothermal liquid droplet is analyzed, and the edge effect of droplet infrared temperature measurement is explained. The data processing method of infrared temperature measurement is given.Zero-dimensional infinite thermal conductivity rate evaporation model and three-dimensional conduction limit evaporation model are built separately. The evaporation of droplet under laser heating is simulated based on previous studies of radiation absorption. The changes of size and temperature are studied and the calculated results are compared with experimental data. It is found that zero-dimensional model under uniform radiation can be used to estimate the droplet evaporation characteristics to some extent, and thermal conductivity limit is not applicable when the internal temperature is extremely nonuniform. |
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