Three-dimensional large eddy simulation of round liquid jet primary breakup in coaxial gas flow using the VOF method

• Liquid inlet velocity distribution has varied effects on nozzles of different sizes.
• A parameter is obtained to assess the importance of inlet velocity distribution.
• An efficient methodology is presented for the numerical study of coaxial atomizers.

Large eddy simulation (LES) was performed on a liquid primary breakup process of twin-fluid atomizers with various dimensions. Volume of fluid (VOF) method was applied to track the unsteady evolution and breakup of the liquid jet. It was observed that the liquid primary breakup morphology of the thin central tube nozzle was more sensitive to the liquid inlet velocity distribution than that of the thick central tube nozzle, and the possible reasons were analyzed. The effect of liquid inlet velocity distributions on the primary breakup morphology was explored in detail. A criterion parameter was defined to assess the relative importance of liquid inlet velocity distributions on the liquid breakup shape of a selected atomizer. The combination of the present numerical scheme and the proper liquid inlet velocity distribution, which was determined by the dimensions of atomizers, was reliable and efficient for the numerical investigation of coaxial atomizer with various dimensions.