Analysis and verification of calculation model of heat transfer coefficient of twin screw in the same direction

In order to reduce the safety risk in the preparation and production of high polymer bonded explosives (PBX) and promote the continuous and large-scale production of PBX explosives, five different ratio of polymer bonded explosives were designed with non-aluminum-containing PBX substitutes as the research object. The calculation model of the heat transfer coefficient between barrel/screw and material based on the change of physical property parameters, structural parameters and operating parameters is derived and established. At the same time, the direction of heat conduction in the screw metering section during the actual extrusion process and the contribution ratio of heat conduction to the temperature rise of the material were discussed. The results show that: The heat conduction is dominant in the heat conversion in the metering section of screw. Especially in the material system with energetic oxidizer : aluminum powder 6 : 2, the heat transfer of the cylinder in the metering section is more than 10 times the viscous heat generation. The heat transfer coefficient calculation model established in this paper is more comprehensive, and the calculated results are between the results of earlier heat transfer research theories. Under the same experimental conditions, the absolute error between the theoretical exit temperature predicted by this model and the experimental measured value is within 0.2°C, and the predicted temperature rise error is within 20%.