Abstract: A heat transfer model was established for rotational molding process heated electrically in heating phase based on static bed model to simulate temperatures at mold surface and inside mold in three cases by means of FLUENT software， and simulated results were compared with experimental results. At first， heating power was assumed to be constant in entire heating phase， and then in the improved model， the intensity of internal heat source at outer surface of mold was set as the one during temperature?increasing stage and the one during temperature?holding stage respectively to simulate variation of heating power. Meanwhile the temperature inside mold was equal to the mass?average temperature of powder and air inside mold before the start of powder melting， and the temperature of air inside mold after the moment. It was indicated that simulating accuracy for temperatures at mold surface by the improved model was higher than that for temperatures inside mold. For the thickness of hydrogen cylinder no more than 10 mm， root?mean?square relative errors of simulated temperatures with tested temperatures at mold surface and inside mold were both within 10 % in entire heating phase. These two root?mean?square relative errors were 5.1 % and 14.1 % respectively for hydrogen cylinder with thickness of 12 mm. In addition， the variation of liquid fraction of plastic layer with time was also obtained from simulated results in three cases.

Key words: electrical heating, rotational molding process, heat transfer model, temperatures at mold surface and inside mold, FLUENT simulation