Question

With respect to the relationship between the power number and the impeller Reynolds’s number, which amongst the following statements is true?

(a) In the turbulent region, the NRe,i has no impact over NPo

(b) In the transient region, the NRe,i has no impact over NPo

(c) In the laminar region, the NPo continually falls as NRe,i increases

(d) None of the mentioned

This question was addressed to me during an interview.

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

Answer 1

Right choice is (a) In the turbulent region, the NRe,i has no impact over NPo

To explain: In the turbulent region, the NRe,i, impeller Reynolds’s number, has no impact over NPo, power number.