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

  • Abstract
  • Keywords
  • References
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  • 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.



  • Keywords

    Crack Length, Thermal Loading, Stress Distribution, J-Integral, Heat Transfer Coefficient, Thermal Conductivity.

  • References

      [1] Rice, J. R, “ Path Independent J-Integral”, Journal of Applied Mechanic, pp379-386, 1968.

      [2] Grebner. H and Strathmeier. U, “ Stress Intensity Factor for Longitudinal Semi-elliptical Surface Cracks in a Pipe under thermal loading “, Journal of Engineering Fracture Mechanics, Vol. 21, No. 2, pp383-389, 1985.

      [3] Raveendra. S. T and Banerjee. P. K, “ Boundary Element Analysis of Cracks on Thermally Stresses Planar Structures “, International Journal of Solids Structures, Vol. 29, No. 18, pp2301-2317, 1992.

      [4] Rizk. A. A, “A cracked Plate Under Transient Thermal Stresses Due to Surface Heating”, Journal of Engineering Fracture Mechanics, Vol.45, No.5, pp687-696, 1993.

      [5] Kim. Y. W and Lee. H. Y and B. Yoo, “ Numerical Evaluation of Stress Intensity Factor for Vessel and Pipe Subjected to Thermal shock “, International Journal of Pressure Vessel and Piping, Vol. 58, pp215-222, 1994.

      [6] Lee K. S and Assanis. D. N,” Thermo-Mechanical Analysis of Optically Accessible Quartz Cylinder Under Fired Engine Operation”, International Journal of Automotive Technology, Vol.1, N.2, pp79-87, 2000.

      [7] Al-Edani. A. A. N, “ Efficient Fracture Mechanics Programming System for Linear and Non-linear Problems Using Finite Element and Boundary Element Methods “, Ph. D Thesis, Cranfield Institute of Technology School of Mechanical Engineering, England, 1990.

      [8] Lee. K. Y and Park. J. S, “J-Integral Under Transient Temperature State”, Engineering Fracture Mechanics, Vol.43, pp931-940, 1992.

      [9] Kuang. J. H and Chen. Y. C, “The Values if J-Integral Within The Plastic Zone”, Engineering Fracture Mechanics, Vol.55, N. 6, pp869-881, 1996.

      [10] Wang. W. Q, Sun. S. S and Li. A. J and Zhou. S. J, “ The Characteristics of J-Integral Under Biaxial Stressing”, International Journal of Pressure Vessel and Piping, Vol.77, pp159-165, 2000.

      [11] Saleh. N. A, “Domain Loading Fracture Mechanic Linear Analysis Using Finite Element Method”, M. Sc. Thesis, Basrah University, Iraq, 1996.




Article ID: 27988
DOI: 10.14419/ijet.v7i4.19.27988

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