Friction forces of particulate plugs moving in vertical and horizontal pipes

Semion Shaul, Haim Kalman

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


This paper presents a comprehensive theoretical and experimental analysis of the friction forces of particulate plugs. Friction forces of particulate plugs play a key role in the estimation of the pressure gradient over a pneumatic conveying pipeline. Therefore, a theoretical model to calculate those forces for variable orientations of the pipe inclination (0. ≤. α. ≤. 90) was developed. In particular, were analyzed the behavior of various parameters such as plug length, plug diameter, internal friction of the material, wall friction, the pressure gradient due to airflow through the plug, and the stress transmission coefficient. The agreement of the new correlations was found to be in the range of ±. 15% for the stress ratio values. Moreover, by substituting these correlations into the newly developed theoretical model and comparing its values to experimental results, an agreement of ±. 30% for the plug friction force calculation was achieved. The present study enables a better understanding of the characteristics of the two-phase (gas-solids) plug flow regime.

Original languageEnglish
Pages (from-to)310-323
Number of pages14
JournalPowder Technology
StatePublished - 1 Jan 2014


  • Dense phase
  • Friction forces of particulate plugs
  • Plug flow
  • Pressure gradient of particulate plugs
  • Stress transmission coefficient

ASJC Scopus subject areas

  • General Chemical Engineering


Dive into the research topics of 'Friction forces of particulate plugs moving in vertical and horizontal pipes'. Together they form a unique fingerprint.

Cite this