Volume fraction equation iteration number determination method and system based on free interface

The invention discloses a method and system for determining the number of iterations of a volume fraction equation based on a free interface, and belongs to the field of multiphase flow numerical calculation research in computational fluid mechanics. The method comprises the following steps: marking a free interface grid unit at the current moment in a fluid model; calculating the Langums of all the free interface grid units at the current moment, and obtaining the maximum Langums in the Langums; and establishing a constraint relationship with the number of iterations of the volume fraction equation according to the maximum number of Langums of the free interface grid units at the current moment and a preset coefficient k so as to determine the number of iterations. According to the method, the minimum number of iterations is dynamically updated according to the maximum library number of the free interface units with different time steps, so that the balance between the calculation precision and the efficienc