Determination of Time Delay and Rate of Temperature Change during Tyre Curing (Vulcanizing) Cycle

Abstract

Abstract Curing is one of the most important steps in the tyre manufacturing process. During this process, a green tyre is formed to the desired shape and the compound is converted to a strong, elastic material to meet tyre performance needs. The process of curing is usually accomplished under pressure and an elevated temperature provided by the mould. The curing process is energy consuming and has a strong effect on material properties. To attain an optimal state of cure for tyre for better quality of product and to minimize the cycle time requires fluid flow analysis inside the tyre bladder. To minimize the temperature difference and for finding out the delay time in OTR tyre curing process, the simulations were carried out using CFD software package ANSYS FLUENT 13. The intent of carrying the CFD analysis is to observe the internal flow physics in a rubber tyre bladder. Transient analysis of 2-D axis symmetric case for a conventional cycle used in OTR tyre curing is presented. The temperature and pressure distribution inside the tyre bladder is simulated by using turbulent SST k-ω model. The temperatures at top and bottom points of bladder are estimated by means of conjugate heat transfer approach. At the end, the results are analyzed and simulated results are validated with experimental data. It was found that the results from the CFD simulation and experiments are in good agreement. Finally, the temperature difference in LTHW circulation is reduced to 4 °C from 38 °C by changing the flow rate at outlet from 15m3/hr to 38m3/hr and delay time is reduced from more than 60 minutes to the 20 minute. Reduction of delay time will improve product quality as well as it reduces utility cost.