The Wall Stress of the Capsule Surface in the Straight Pipe

Hydraulic capsule transportation is a new energy-saving transport mode. It is of great significance to the study of flow-field characteristics and pipeline-stress analysis. The purpose of this paper was to analyze the stress distribution on capsule surfaces when there is stationary in pipe flow. Results showed that the maximum shear stress on the capsule wall appeared in the rear section. Shear-stress range was between 0 and 38 Pa. Principal stress exerted great force on the capsule. The circumferential component of the principal stress was the largest, followed by the axial component, and the radial component was the smallest, i.e., sigma(c) > sigma(a)> sigma(r). The larger the discharge of pipe flow, the greater the influence of unit discharge on wall shear stress and capsule principal stress, that is, k(1) < k(2)< k(3). Under the conditions of this experiment, the axial component of principal stress should include shear stress on the capsule, and Reynolds stress on the capsule cannot be neglected due to water-flow turbulence.