Some examples of application of the mathematical flow model proposed by Wolf and Resnick for the glass melting process optimization have been presented. The model description of the process was verified experimentally. The tracer selection criteria have been discussed. The method of radiotracer injection and the detection – recording apparatus have been described. The examples of parameters' values of the tank furnaces operation have been calculated. Tank furnaces of different design and final product were considered. Some general conclusions as well as technological recommendations formulated on the grounds of radiotracer investigations and with use of complex flow model of the molten glass have been presented.