Flash Evaporation experimental apparatus consists of a high pressure Flashing atomization can occur in liquids subjected tank feeding high pressure and high temperature to sudden pressure drop or sufficient superheating water to the nozzle, the liquid collecting vessel, high which leads to formation of vapor bubbles inside the speed camera and the measuring instruments at liquid. Rapid growth of bubbles is the cause of the different location of the system. The pressure is explosion of the bubble and generation of finer generated by the air above the liquid level in the tank droplets and spray. Therefore, this phenomena has which is pressurized by air pressure amplifier. This direct effect on the droplet formation and size as well apparatus, under controlled pressure and temperature as general shape of the spray. can generate a good simulation of flash evaporation In splash plate nozzles due to the high temperature in the actual splash plate nozzle. Measuring the size and pressure flashing is so likely to occur and affect and distribution of the droplets will be performed by the performance of the recovery craft boiler means of the camera and analyzing the pictures dramatically. obtained from different tests. This study is going to explore the flashing To predict the characteristics of the sheet in different evaporation in splash plate nozzles in analytical, circumstances, a theoretical approach will be experimental, and numerical ways. Studying the constructed based on theories existing in the theory and published research works related to this literature. The theory and its agreement with the area is the first step. The unknowns of the study are experimental results can enhance the legitimacy of flashing type in this nozzles, evaporation ratio, effect the results and conclusions of the study and hence a of flashing on droplet formation, size and critical step to attain the goal of the study. distribution, effect of flashing on jet size and flashing and correlations between temperature or pressure of the liquid and the above characteristics. In order to explore the aforementioned issues, an experiment will be designed and different materials based on the stage of the study will be tested as the flashing liquid to model the black liquor. The