Question

Power required for a gassed system is more than that required for an ungassed system.

(a) True

(b) False

I had been asked this question in final exam.

This intriguing question originated from Unit Operations in division Sedimentation and Centrifuge, Mixing, Size Reduction and Separation and Material Handling and Transportation of Food Engineering

Answer 1

Right option is (b) False

The explanation is: Power required for an ungassed system is more than that required for a gassed system. This is because when gas is sent into the fluid via a nozzle, the density of the fluid near the impeller decreases and hence the power required for it is lesser.