The pressure relationships of the particle exchanges in horizontal slug flow pneumatic conveying

The sustained research effort into pneumatic conveying, that has spanned decades, continues to pursue a means of designing reliable systems in practice. The measure of success is the ability to consistently predict the pressure drop of a proposed system. In horizontal slug flow pneumatic conveying, the complex interactions between the two conveyed phases, as well as their interaction with the pipe wall, often result in difficult to validate assumptions that accumulate for several parameters throughout the modelling process. This paper presents an experimental investigation that directly measures the pressure drop due to the particle exchanges between a slug and its stationary layers, a parameter that previously has never been measured directly. Conveying an Inertial Measurement Unit (IMU) with an on-board barometer, that mimicked the motion of the particles, and comparing the results to a fixed pressure sensor, it was possible to deduce the relationship between the slug and particle pressure drops. Analysis showed the pressure drop due to the particle exchanges is a constant and approximately 5-10% of the total pressure drop. In the high pressure drop region, a divergence was observed in the data where the slope increased between the slug and particle pressure drops. This result was hypothesised to be due to the high pressure drop region corresponding to longer slugs, which may be at a lower fluidised state.