Study the Effect of Heat Transfer Coefficient and Thermal Conductivity on Cracked Pipes Carrying Pressurized Fluid

Abstract

The cylindrical pipes carrying pressurized fluid at high-temperature environment have many engineering applications such as cooling systems of the power plant. In this paper, the effect of the presence of crack and the thermal stress distribution of the pipe has been studied numerically. The “mode I†type of crack has been considered for the study. The stress distributions, stress intensity factor and J-integral calculations were considered. The results have been validated with an available analytical solution for a pristine cylinder. Special attention and mesh scheme has been used around the crack to obtain the accurate stress distributions. The temperature and stress variations for pressurized fluids with different heat transfer coefficients and pipe’s conductivity were studied. It was found that the convection heat transfer coefficient has an accountable effect on the stress distributions. The stresses increased by 5% for different heat transfer coefficient without cracks. Moreover, the stress intensity factor and the J-integrals were calculated for different crack length ratios. The stress intensity factor increased by 14% when the crack length ratio is 0.7. In addition, the effect of pipe thermal conductivity has been studied. It was found that the thermal conductivity influences the stress distributions, stress intensity factor and J-integral values. The stresses decreased by 15% with increasing the thermal conductivity without cracks, the J-integral and the stress intensity factor decreases as the thermal conductivity of the pipe increases for different crack length ratios.