The pipeline flow of capsules: Part 3 ‐ An experimental investigation of the transport by water of single cylindrical and spherical capsules with density equal to that of the water

As the first part of an experimental investigation of the transport of shaped solids through pipelines, laboratory studies have been made on the transport of single cylindrical and spherical capsules by a stream of water, the capsules having the same density as the water. The studies were concerned with the effects of water velocity and capsule/pipe diameter ratio on the velocity of both cylindrical and spherical capsules, and also with the effects of capsule length/diameter ratio and end-shape on the velocity of cylindrical capsules. The investigation was carried out in a 35-ft. horizontal length of 1 1/4 in. diameter transparent acrylic plastic pipe. The velocity of the capsules was found to vary from 1.05 to about 1.5 times the average water velocity, which ranged from 0.20 to 12.15 ft./sec. A decrease of diameter increased the velocity of both cylindrical and spherical capsules relative to the average water velocity. Increasing the length of cylindrical capsules had a similar effect, while an ellipsoidal nose increased the velocity of smaller diameter cylindrical capsules, but the effect on the largest diameters was negligible. The presence of a capsule appeared to delay the onset of turbulence in the annulus between the capsule and the pipe wall to a much higher value of Reynolds number than would hold in unobstructed fluid flow. Des etudes en laboratoire ont ete entreprises sur le transport de capsules cylindriques et spheriques de měme densite que l'eau, dans un courant d'eau. Les variables etudiees sont: vitesse de l'eau, rapport des diametres capsule/tuyau, rapport longueur/diametre et geometrie des extremites des capsules cyclindriques. Un tuyau transparent de plastique acrylique d'une longueur de 35 ft. et diametre 1 1/4 in. a ete utilise dans cette recherche. La vitesse des capsules a varie de 1.05 a 1.5 fois la vitesse moyenne de l'eau dont la vitesse a varie de 0.20 a 12.15 pi/sec. II a ete determine que la vitesse des capsules augmente relativement a la vitesse moyenne de l'eau, avec une diminution de diametre des capsules cylindriques et spheriques et avec une augmentation de la longueur d'une capsule cylindrique. D'autre part une geometrie amont ellipsoidale augmente la vitesse des capsules cylindriques de faible diametre. Cette augmentation de vitesse est negligeable pour des capsules de gros diametre. La presence de capsules retarde l'apparition de turbulence, jusqu'a des Re beaucoup plus eleves, dans l'espace annulaire cree entre le capsule et le tuyau.