The Application Research Of Finite Element Method In Glass-lined Pressure Vessel

The Glass-lined pressure vessel(GLPV)is widely used in pharmaceutical,chemical and other industries due to its excellent corrosion resistance and surface finish.However,the failure caused by exploding porcelain often occurs in the GLPVs during the manufacture and operation.The residual stress is induced by the firing process leading to a complex distribution of stress in the enamel coating.Therefore,it is a key issue to unveil the distribution of residual stress in the GLPVs and establish the failure criterion of the enamel coating in the design and manufacture.A simplified method of finite element analysis(FEA)for the GLPV was proposed in current work and verified by the experiments of the enamel C-ring specimens.The factors of residual stress were analyzed by FEA in the GLPVs with different sizes.In order to reveal the failure mechanism of the enamel coating in the GLPVs,the tensile experiments with two types of standard specimens with and without enamel coating were carried out.The cracks in the enamel coating were detected by the acoustic emission test system.Comparing the tensile curves of the two different types of specimens,the stress distributions of the metal substrate and enamel coating were studied in this paper.The tensile experiments were also conducted towards the plane specimens with enamel coating.The center-hole and fillet were machined in the plane specimens.The stress distributions of the metal substrate and enamel coating at the edge of holes were simulated by FEA.The failure criterion of enamel coating was discussed in the condition of tensile stress.The main conclusions can be drawn as below:(1)The feasibility and accuracy of the simplified method were confirmed by the experiments of firing process and FEA in this work.The simulation of the residual stress was further simplified when the modified factor of enamel coating's properties was introduced..(2)The results of FEA revealed that the maximum of the principle stress in the enamel coating was decreased with the increasing radius of the nozzle fillet.Meanwhile,the maximum of principle stress was reduced with the less difference between the linear expansion coefficients of metal and enamel coating.The thinner thickness of the enamel coating produced a deduction of the residual stress at the fillet in the nozzle.If the nozzle inner diameter at 65mm,it also reveal that The decline of the maximal value of residual stress in the enamel coating was significant when the fillet radius of metal substrate was below 5 mm and became steady when the fillet radius reached 15mm.(3)The failure criterion of the enamel coating in GLPVs was proposed by the study of the experiment and FEA.It is necessary to control the tensile stress in the enamel coating and keep the metal substrate being out of yielding simultaneously.This criterion will be beneficial to the development of the standard and design in GLPVs.