Question

Questions about pipr flow experiment

1. What causes dynamic head loss

2. Should the values for expcted f similar to theoretical f? Justify your answer

3. What assumptions did you make in determining the theoretical friction factor?

4. How severe are minor losses compared to major losses

5. Is pipe bend or pipe angle preferred as a fitting? Why?

6. Briefly write your observations regarding minor losses

Answer 1

Hope it helps.

1- Friction in a pipe and internal friction present in fluid layer (viscosity) causes reduction in velocity of flow of fluid in a pipe. Major losses in pipe is generally caused by friction in pipe. Dynamic head loss is caused by the variation in velocity in pipe.

2- Theoretical value of friction factor 'f' is determine by the formula (fLv2)/2gd which is obtained by the pipe flow experiement. Pipe flow experiment assumed some conditions of flow which is quite different from the actual conditions. So, the expected value is slightly different than theoretical friction factor.

3- The assumptions made in pipe flow experiment are-

a) Flow should be steady flow.

b) Pipe should be horizontal so that potential energy become constant throghout the flow in a pipe.

c) Velocity of flow should be same at entrance and exit of pipe which results constant kinetic enegy.

d) Incompressible flow i.e. the density of fluid is same in a pipe.

e) It should follows equation of continuity i.e. discharge in pipe should be constant.

4- Due to minior losses, non-uniformities in flow path created and this may cause a small change in energy but in case of major loss the energy loss is larger than minor loss.

5- Pipe bend has unspecified bending radius and degree of angle but in case of angle (pipe elbow) the bending radius and angle is specified by some standards. Elbow can change direction according to the requirement for pipe fitting. Pipe bends are prefer for fittinng where the problem is with the pressure drop.

6- Minor losses are generally caused by change in pipe bend, cross section of pipe. Minor losses include sudden enlargement and contraction of pipe section, losses at entrance and exit and in pipe bend or pipe obstruction. Minor losses along with major loss may cause pressure drop in pipe. To reduce minor losses, pipe should be uniform and the velocity of flow under the pipe should be design velocity.