A Non-Dimensional Consideration in Combustor Axial Stress Computations
Thermal stresses in the combustor of gas-turbines are computed using non-dimensional parameters. Buckingham pi theorem was used to arrange the listed relevant parameters into non-dimensional groups. In testing the validity of the functional relation of the non-dimensional independent parameters, use is made of the prevailing temperatures of the combustor in operation. A computer program was used to enhance computations. The results showed an interesting way of influencing the axial stresses. To reduce stresses in gas-turbine combustors, a method of varying the independent parameter that is of radius ratio oriented and thickness dependent was adopted. This showed a reduction of the axial stresses to minimal levels using the parameters. Plots were made and a point of inflection that manifested itself in the presentation of the axial stress function was further investigated upon. It turned out to be a point of abnormal stress level and out-of-trend temperature profile. The use of non-dimensional consideration proved adequate in the computation of axial stresses. The results showed a 2 percent difference from existing values of stresses got from a transient thermal loading of a combustor.
THREE-DIMENSIONAL TRANSIENT THERMAL STRESS ANALYSIS OF A NONHOMOGENEOUS HOLLOW CIRCULAR CYLINDER DUE TO A MOVING HEAT SOURCE IN THE AXIAL DIRECTION
In this paper, a theoretical analysis of a three-dimensional transient thermal stress problem is developed for a nonhomogeneous hollow circular cylinder due to a moving heat source in the axial direction from the inner and /or outer surfaces. Assuming that the hollow circular cylinder has nonhomogeneous thermal and mechanical material properties in the radial direction, the heat conduction problem and the associated thermoelastic behaviors for such nonhomogeneous medium are developed by introducing the theory of laminated composites as one of theoretical approximation. The transient heat conduction problem is treated with the help of the methods of Fourier cosine transformation and Laplace transformation, and the associated thermoelastic field is analyzed making use of the thermoelastic displacement potential, Michell's function, and the Boussinesq's function. Some numerical results for the temperature change and the stress distributions are shown in figures, and the effect of relaxing the thermal stress ...
TRANSIENT THERMAL STRESS AND DEFORMATION OF A LAMINATED COMPOSITE BEAM DUE TO PARTIALLY DISTRIBUTED HEAT SUPPLY
Abstract This paper is concerned with a two-dimensional transient thermal stress analysis of a laminated beam due to a partially distributed heat supply. The beam is composed of different materials in multilayers. For the laminated composite beam we use the finite cosine transform and the Laplace transform for the temperature field and we adapt the elementary beam theory to the thermoelastic field. We then evaluate the temperature change, thermal stress distribution, and thermal deformation in a transient state. We apply the proposed theoretical method to the analysis of a beam with nonhomogeneous material properties, and examine the distributions of thermal stress and thermal deformation and the effect of relaxation of the stress distributions in a nonhomogeneous beam.