Question

Determine the transition length at the entrance to a 10 mm tube through which 100 percent glycerol at 60 C is flowing at a velocity of 0.5 m/s. The density of a glycerol is 1240 kg/m Data: The dynamic viscosity is 0.0813 Pa-s. a) 18.13 mm b) 50 mm c) 45.43 mm d) 38.13 mm

Answer 1

Answer: Option (d) is the correct answer.

Step-by-step explanation:

The given data is as follows.

Tube diameter d = 10 mm = 0.01 m

Velocity of glycerol, v = 0.5 m/s

Density of glycerol (
`\rho`) = 1240 kg/m3

Dynamic viscosity of glycerol (
`\mu`) = 0.0813 pa.s

Reynolds number (Re) =
`\rho * velocity * (density)/(\mu)`

=
`1240 * 0.5 * (0.01)/(0.0813)`

= 76.26

Therefore, according to Reynolds number we can say that flow is laminar.

Lt =
`0.05 * Re * d`

=
`0.05 * 76.26 * 0.01`

=
`0.03813 m`

As it is known that 1 m = 1000 mm. Hence, in 0.03813 m will be equal to
`0.03813 m * (1000 mm)/(1 m)`

= 38.13 mm

Thus, we can conclude that the transition length of glycerol is 38.13 mm.