Current studies for the prediction of conveying pipeline pressure drop in low velocity dense phase pneumatic conveying are generally based on steady state analyses although some experimental and numerical investigations illustrate that the flow mechanics involved in dense phase pneumatic conveying have time-dominate effects rather than those of steady state. Due to the steady state approach for pneumatic conveying pipeline, limited improvements in accuracy have been provided.
An attempt for investigation of several mechanisms which occur in pneumatic conveying pipelines, such as investigation of two-phase and periodic flow together, complicates the theoretical approaches and experimental study conditions. For this reason, the systematic studies should be performed for such complex mechanisms. Firstly, one-phase periodic flow dynamics and then two-phase steady state flow dynamics can be investigated and finally a linkage between these two separate scenarios can be obtained by a superposition.
The approach herein is that the steady state flow in conveying systems behaves as time-dependent flow. So, it is firstly necessary to understand the flow dynamics of time-dependent pipe flow in one-phase gas flow rather than the two-phase flows. In this respect, the paper represents an experimental investigation on time-dependent flow characteristics of air flow in horizontal pipeline to understand the flow characteristics of pneumatic pipeline flow. Due to the variation of pressure fluctuation level, depending on material type in conveying pipelines, it is inevasible to investigate velocity and pressure fluctuation profiles of pulsatile flow. So the one-phase periodic flow dynamics are discussed herein in the range of oscillation frequency of 0.1 Hz<f<40 Hz.