The distribution of a viscous liquid through a perforated tube

Abstract

One of the methods by which a slab of material can be made is by laying down a mixture of liquids that react and form a solid. This can be done by passing them through a moving perforated tube. A problem often experienced in such equipment is that liquid can spend too long somewhere within the tube so that solidification takes place prematurely and the tube becomes blocked. An experimental study of the flow of a viscous liquid through a perforated tube has been undertaken to identify where and why this may occur and how it might be eliminated. Most of the liquid flows straight through the tube and the perforations and has a short residence time; however, an air pocket forms at the end of the tube near which there is a region of slowly moving or stagnant fluid. This pattern does not seem to be affected by the presence of holes upstream nor to be very sensitive to fluid viscosity, and cannot be wholly prevented by changing the position of the final hole. However, the amount of slow-moving liquid can be much reduced by altering the geometry of the end of the tube so that it tapers towards the end.