Fluid Flow and Pipes

Question 1

What is the mechanical energy balance?

Answer 1

Potential energy (g delta z)
-
Expansion work (the integral of dp/Rho)
\+
Kinetic energy change (delta (v^2/2))
=
Work added/subtracted by pumps or compressors (Wo)
-
Sum of the friction losses

Question 2

The mechanical energy balance is per what?

Answer 2

Unit mass

Question 3

In fluid flow through a pipe, what parts of the mechanical energy balance can be ignored?

Answer 3

Work terms

Question 4

If the pipe is at an angel what does g (dZ/dL) equal to?

Answer 4

G*sin(theta)

Question 5

The fanning friction factor is proportional to what?

Answer 5

Velocity squared

Question 6

The fanning equation applies to what kind of fluids?

Answer 6

Single phase

Question 7

Where can you find the friction factor?

Answer 7

Moody Diagram

Question 8

Pressure drop for valves and fittings is accounted for as what?

Answer 8

Equivalent length of pipe

Question 9

For an incompressible fluid, what is constant, and what term goes to zero in the mechanical energy balance?

Answer 9

Rho (density); delta v (velocity)

Question 10

What is the isothermal incompressible integral form of the mechanical energy balance?

Answer 10

Delta p = -rho [gdelta Z+2v^2f*((L+Le)/D+sum of friction losses

Question 11

For nonisothermal but incompressible flow (liquids), you will not have a big error if you use rho at the average what?

Answer 11

Temperature

Question 12

For small pressure drops you can use what?

Answer 12

Bernoulli and fanning equation

G/v^2)*dz+(1/v)dp+(V/v^2)dV=-(del F/v^2

Question 13

Volume is equal to what?

Answer 13

Velocity times the mass flow rate divided by the area.

Question 14

The compressible flow algorithm can be applied when what?

Answer 14

The relative difference between the pressure changes is 20 to 30%

Question 15

When capital investment decreases what usually increases?

Answer 15

Operating costs

Question 16

Pipes are not equivalent to what?

Answer 16

Tubes

Question 17

What is bursting pressure equal to?

Answer 17

2tensile strength(wall thickness/mean diameter)

Pb=2St(tm/Dm)
Pb=Pinside - Poutside

Question 18

Safe working stress should be less than what?

Answer 18

Tensile strength

Question 19

What is the range of safe working pressures?

Answer 19

6500 - 9000 psi at temperatures less than 250 F

Question 20

What is the schedule of a pipe?

Answer 20

Sch=100*(working pressure/allowable stress)

Question 21

You specify a pipe by giving what?

Answer 21

The diameter and the schedule

  * get pressure inside (psia)
  * Ps = Pin - 14.696
  * alpha = 1000 (Ps/Ss)
  * pick lower possible Sch standard Sch>alpha