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Flow rate through nozzle - effect of viscosity

Thread starter chris53
Start date Oct 1, 2003

Status: Not open for further replies.

Oct 1, 2003

chris53

Materials

This question relates to liquids pumped through swirl type nozzles. Normally a slurry with a measured viscosity of around 0.2 Pa.s (200 cps)and density about 1.5 g/cm3 is pumped into the nozzle at 30 bar. Nozzle diameter is 1 mm. Flow rate is about 100 litres/hour. When the process is shut down the slurry is replaced by water (viscosity 0.001 Pa.s, 1 cps) but the flow rate seems to remain about the same or maybe even a little less. Why is this? Is it due to the change in Reynolds number which I reckon is about 30,000 for the slurry and about 200 for the water (based on the nozzle diameter)? Arether any formulae to predict the effec of viscosity on the flow rate thorugh this type of system?

Thanks.