Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.
This paper evaluates the performance of different nozzle
geometries which are all used in industrial blowing
applications. Five different geometries were selected: a
converging nozzle, a stepped nozzle, a straight pipe, a
converging-diverging nozzle and an energy-efficient nozzle.
The flow field of the various nozzles was calculated using CFD
simulations. The compressible RANS equations were solved
using the SST k-omega turbulence model. Different properties,
like the total impact force, the impact pressure and the
entrainment rate were obtained from the simulations to
compare the nozzles with each other. For each of these
properties, the most efficient nozzle was the one for which the
mass flow rate of compressed air was the lowest. All nozzles
showed comparable mass flow rates for the same impact force
and the difference was in the order of 5% better than a straight
pipe geometry. Only the energy saving nozzle used around 10%
less mass flow and is the best solution to reduce compressed air
consumption without losing performance.