Online calculation method for blast furnace center airflow

The invention discloses an online calculation method for blast furnace center airflow size, and belongs to the technical field of metallurgical production processes. The invention provides an on-line calculation method which is beneficial for field operators to accurately monitor the fluctuation condition of blast furnace gas flow in real time and maintain the stable, simple, accurate and efficient furnace condition, and the on-line calculation method comprises the following steps: carrying out at least two times of image processing on a real-time image of an upper charge level of a blast furnace; the method comprises the following steps: acquiring a gray calculation gradient map with gradient, calculating the calculation center airflow radius of the gray calculation gradient map and the position of the center airflow on a charge level, calculating the actual area Sc of the center airflow and the actual area SBF of the charge level on the basis of the calculation center airflow radius, and calculating the pro