Thermal expansion analysis of air hoses produced from different elastic materials

This paper was written to examine the thermal expansion analysis of four different hoses of the same geometric shape and dimensions, produced from rubber types with different raw materials. Thermal analyzes are solid-liquid interactive (FSI) analyzes. In the FloEFD program, the pressure value and distribution of the hose geometry were determined. This pressure distribution was transferred to Ansys program and the deformation created by the pressure forces on the hose was examined. Hoses are made of EPDM, ECO, AEM and NBR/CSM rubber pulps. Manufacturing and test process was carried out in Elatek Rubber which is operating in Bursa Dosab. The dough produced is subjected to the necessary material tests and the dough is subjected to extrusion and vulcanization, after the confirmation. Produced hoses are subjected to diameter expansion test in the performance test laboratory. Fluid was passed through the hoses at 100°C and 140°C, at the pressure values specified in the test specifications. At the end of the test, the difference between the first and last diameter was expressed. This process was carried out for all hoses. The hose geometry is transferred to the FloEFD to specify the appropriate boundary conditions and the optimum mesh structure. The results are compared with the pressure loss obtained in the test and thus the accuracy of the model is confirmed. These results are input for FEA analysis. Rubbers are not standard materials. Therefore, tensile test was performed to determine the material properties of rubber. The tensile specimen was cut over the hoses made of four different rubber types. Stress-strain graphs of the hoses tested with tensile test device were obtained. The mechanical properties of the material were successfully transferred to Ansys with the elasticity module obtained from these graphs. According to the results of the analysis, there is an average expansion of 1-2 mm in all hose types. When the diameter expansion test and analysis results at 100°C are compared, it is seen that the results obtained are compatible with each other. As expected, the amount of expansion obtained from the diameter expansion test at 140°C is higher than the results obtained at 100°C. This proves the theory that the relationship between temperature and the amount of expansion is linear. CFD analysis results at 140°C and the results obtained at 100°C are almost the same. Therefore, When the diameter expansion test at 140°C and the analysis result are compared, the difference is higher than the difference at 100°C. The maximum temperature that rubber hoses can withstand is 150-180 ° C. However, the study has shown that some of the deformation of the rubber structure can be seen at lower temperatures. Therefore, the modeling of rubber hoses as solids in the analysis leads to the misinterpretation of the analysis results and consequently the operating conditions of the system. Performing analysis according to the deformed hose will prepare us for the worst case in order to achieve the best interpretation and to obtain the best performance in systems using rubber hoses.