Numerical and experimental investigation of flow behavior in a confluent jet ventilation system for industrial premises
2012 (English)Conference paper (Other academic)
A conventional supply principle, such as rmxing or displacement ventilation, in industrial applications often results in low ventilation efficiency and high draught. A possible way to improve the ventilation efficiency in industrial premises is to implement a new type of supply system known as confluent jet ventilation. The confluent system can be described as a number of free jets issued in a plane, parallel to each other. In the proximity of the diffuser, the confluent jets behave as separate jets, but downstream the jets starts to merge with each other and eventually behave as a single jet. The main advantage of the confluent jet system is its ability to conserve momentum in an efficient way. The high level of momentum makes the ventilation system less sensitive to mechanical disturbances and buoyancy forces than displacement ventilation. This effect can be used to enhance the ventilation efficiency.
The purpose of this study is to investigate both numerically and experimentally the flow behavior of a confluent jet system in the region close to the diffuser.
In the present study, a diffusor consisting of 36 jets with an in-line anangement using equidistant spacing has been studied. The Reynolds number of the jet, based on the nozzle diameter, is Red= 3290. ARANS simulation using the Reynolds Stress Model (RSM) has been used to predict the mean velocity field and the tmbulence characteristics of the confluent jet configuration. The numerical simulations are compared with measurements using Particle Image Velocimetty (PIV), performed in a region extending out to a downsttream distance of 26 times the nozzle diameter. The flow behavior of the confluent jets showed good agreement with the experimental results.
Place, publisher, year, edition, pages
Confluent jet ventilation system, Near zone behavior, PIV measurements, CFD, Reynolds Stress Model
IdentifiersURN: urn:nbn:se:liu:diva-89789OAI: oai:DiVA.org:liu-89789DiVA: diva2:609686
The 10th International Conference on Industrial Ventilation, September 17-19, 2012, Paris, France
ProjectsEtt nytt ventilationskoncept för industrilokaler
FunderSwedish Research Council, 2008-31145-61023-37