Agitation And Aeration

Question: For laminar flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Rei is Reynolds number for agitator; Di, stirrer diameter and N, stirrer speed)
[A].

Np = K(Rei)-1

[B].

Np = N2Di(Rei)-1

[C].

Np = K(Rei)

[D].

Np = KNDi(Rei)-2

Answer: Option A

Explanation:

No answer description available for this question.

Question: Transient flow range of mixing speed is obtained for
[A].

Rei<10

[B].

10<Rei<104

[C].

Rei&gt104

[D].

None of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: Turbulent flow range of mixing speed is obtained for
[A].

Rei<10

[B].

10<Rei<104

[C].

Rei>104

[D].

None of these

Answer: Option C

Explanation:

No answer description available for this question.

Question: Laminar flow range of mixing speed is obtained for
[A].

Rei<10

[B].

10<Rei<104

[C].

Rei>104

[D].

None of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: Power number is expressed as
[A].

P0 / N2Di3ρ

[B].

P0 / N3Di5ρ

[C].

P0 / N3Di3ρ

[D].

P0 / N2Di2ρ

Answer: Option B

Explanation:

No answer description available for this question.

Question: Power number is ratio of
[A].

imposed forced to intertial force

[B].

bouyant force to inertial force

[C].

gravitation force to inertial force

[D].

imposed force to gravitational force

Answer: Option A

Explanation:

No answer description available for this question.

Question: Power number (Np) is also known as
[A].

Froude’s number

[B].

Bond’s number

[C].

Newton’s number

[D].

Rayleigh’s number

Answer: Option C

Explanation:

No answer description available for this question.

Question: Reynolds (Rei) number for the impeller is given by (where Di, stirrer diameter; N, stirrer speed, ρ, density of fluid and μ, viscosity of fluid)
[A].

DiVρ/μ

[B].

Di2Nρ/μ

[C].

Di2Vρ/μ

[D].

DiNρ /μ

Answer: Option B

Explanation:

No answer description available for this question.

Question: Power consumption by agitation is
[A].

a function of physical properties

[B].

a function of operating conditions

[C].

a function of vessel and impeller geometry

[D].

all of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: The power consumption in a stirring vessel can be assessed by using a
[A].

dynamometer

[B].

strain gauge attached to agitator shaft

[C].

watt meter attached to agitator motor

[D].

all of these

Answer: Option D

Explanation:

No answer description available for this question.