To calculate the shrinkage of an isolated hot spot, first determine the isolated region, and then use the formula to calculate the volume shrinkage of all grid elements in each isolated hot spot within the m-th time step. The calculation formula is as follows:
Where, Δ VM is the total volume shrinkage; N is the total number of units without solidification in the isolated hot spot; Solidification shrinkage and liquid shrinkage of unit I. It can be calculated by the following formula:
Where, α S1 is the liquid shrinkage coefficient of alloy casting; β Is the solidification shrinkage coefficient of alloy castings; Fmsi is the solid fraction of element I in the M-1 time step; VI is the volume of unit I; Δ Fmsi is the value of the increase of the solid rate of the element in the m-th time step.