DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
Investigation of exit loss of cooling towers at different wind speeds and Archimedes numbers
Краткое описание
The mass flow rate of the cooling air is a very important governing parameter for cooling towers. Its value results from the balance of the pressure losses and the natural draught. For accurate modelling of the tower performance these losses needs to be known for all working conditions.
The two most important parameters this performance are the wind speed at the cooling tower site, and warming
up of the air inside the cooling tower provided by the heat exchangers.
Wind tunnel experiment was carried out to investigate the wind effect on the exit loss by mimicking the high
Reynolds number effect by surface roughness.
Furthermore the wind effect on the exit loss on a real size cooling tower was simulated by using SAS. Archimedes
number of 0.6, 1.3 and 2.3 situations were investigated for a wind speed (ω) to tower exit velocity (c) ratio between ω/c = 0 − 2...4.
When increasing the wind velocity the exit loss coefficient decreases slightly. In the next region its value is increased to maximum being hardly above no wind condition. In the last region, i.e. above a certain wind speed, the exit loss coefficient is continuously decreasing. As a matter of fact in this last region the wind is increasing the cooling performance at the exit of the tower.