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Characteristics of the mean flow patterns and structure of turbulence in spiral gas streams
Author(s) -
Schowalter W. R.,
Johnstone H. F.
Publication year - 1960
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690060427
Subject(s) - turbulence , mechanics , vortex , physics , cyclonic separation , radius , mean flow , turbulence kinetic energy , geometry , spiral (railway) , flow (mathematics) , inlet , geology , mathematics , mathematical analysis , computer security , geomorphology , computer science
Measurements were made of the flow structures in two types of spiral flow fields. The first was a vortex tube in which air entered one end of an 8‐in. pipe through an involute entry and left at the opposite end. The second was a conventional cyclone separator in which the same entry was used. The experimental results show that the mean and turbulent flow structures are not sensitive to changes in the flow rate, but they are greatly affected by the geometry of the system. In the vortex tube the angular velocity is nearly constant at radial distances less than one‐half of the radius of the pipe. The flow patterns in the vortex tube and in the cyclone are not symmetrical with the pipe axis. The asymmetry can be explained by postulating a dynamic center line with helical shape. The longitudinal intensity of turbulence increases sharply near the center of the vortex tube. This is caused primarily by the abrupt decrease in mean velocity near the center. The radial intensity also increases near the center, but near the wall it decreases rapidly with distance from the center. The longitudinal intensity of turbulence in the cyclone is highest near the center and near the wall. The high intensity near the wall is caused both by the decrease in mean velocity and the increase in root‐mean‐square turbulent velocity.