Chapter 3, Problem 3.11P

(a)

Interpretation Introduction

Interpretation:

The type of flow at temperature $200°\text{C}$ is to be determined.

Concept Introduction :

Reynolds number is the ratio of inertia forces to the viscous forces. It is used to check the type of flow of fluids through pipe and tubes.

The formula of Reynolds number is,

  ${\text{N}}_{\mathrm{Re}}=\frac{\rho VD}{\mu }$

As the temperature is increased from $100°\text{C}\text{to}200°\text{C}$ , there will be a slight change in density of the fluid and velocity increases in same proportion.

The variation of viscosity with the temperature is given as:

  $\frac{{\mu }_2}{{\mu }_1}={\left(\frac{T_2}{T_1}\right)}^{0.65}$

(b)

Interpretation Introduction

Interpretation:

The type of flow on increasing tube size is to be determined.

Concept Introduction :

Reynolds number is the ratio of inertia forces to the viscous forces. It is used to check the type of flow of fluids through pipe and tubes.

The formula of Reynolds number is,

  ${\text{N}}_{\mathrm{Re}}=\frac{\rho VD}{\mu }$

The diameter of the tube is inversely proportional to the square root of velocity.

The relationship between diameter and velocity is given as:

  $\frac{D_1}{D_2}=\sqrt{\frac{V_2}{V_1}}$

By suing the above relationship, find out the velocity at increased diameter.

(c)

Interpretation Introduction

Interpretation:

The type of flow at increased pressure is to be determined.

Concept Introduction :

Reynolds number is the ratio of inertia forces to the viscous forces. It is used to check the type of flow of fluids through pipe and tubes.

The formula of Reynolds number is,

  ${\text{N}}_{\mathrm{Re}}=\frac{\rho VD}{\mu }$

The density of the fluid is affected by the pressure.

The relationship between density and pressure is given as,

  $\rho =\frac{PM}{RT}$

On increasing the pressure, the density also increases but the velocity decreases in the same proportion.