Subject: Fluid Mechanics 2

Topic: Laminar flow

Difficulty: High

Oil of specific gravity 0.9 is pumped through a horizontal pipeline 200 mm in diameter and 3km long at the rate of $0.015 m^3/s.$ the pump has an efficiency of 68 % and requires 7.5 kW to pump the oil. What is the dynamic viscosity of oil and whether the flow is laminar or not?

Given :

Specific gravity $= 0.9$ of oil

Density $= 900 $ kg/m³

d $ = 200 $ mm $ = 0.2$ m

L $= 3 $ Km $= 3000$ m

Q $= 0.015$ m³/s

Power (P) $= 7.5$ KW

$ \begin{array}{I} \eta=68 \% \end{array} $

Solution :

Let

$\begin{aligned} …