Friction comienzo

Group#3 Fluid Mechanics LaboratoryMay 4, 2016 Prof. Pablo Traverso

Jorge A. Sepúlveda MaldonadoOmar D. Serrano Muñiz

Edgared M. Troche MuñizSuchain M. Vélez Ramírez

Determination of head loss through different devices & comparison with theoretical values

• Objectives• Theory• Equipment• Procedure• Data• Calculations• Safety

Agenda

• Sudden Contraction vs Sudden Enlargement• 17.5mm Smooth bore vs roughened test pipe • Gate valve vs ball valve• Venturimeter vs Orifice Plate vs Pitot-static Tube

Objectives1. Determination and comparison of head loss through:

2. Comparison of the coefficient of discharge of the venturimeter with the theoretical value.3. Comparison of the friction factor obtained graphically from Moody Diagram with an experimental value.

Objectives

A fluid is a substance capable of flowing and it changes its shape at steady rate when acted upon a force, shear stress.

A fluid is also identified by its viscosity.

Theory

We will be calculating the head loss in a smooth pipe as well as a rough pipe. For both systems the same equation for closed circular conduits applies:

 Darcy-Weisbach equation

Head Loss due to Friction

**This equation, based on experimental data and theory, relies on the Darcy friction factor ().

Head Loss due to Friction (cont.)Darcy-Weisbach equation

hf =

Flow Control Valves

Used to regulate the movement of a fluid through a piping system. Posses an adjustable “Fitting Factor” (K) that is directly proportional to the Head Loss (h) through the following equation:

h(mH2O) =

Head Loss Due to Pipe Fittings

**We will be finding experimental values of head loss using the manometer and calculate the K- value verifying it remains constant under the given flow rate.

Ball Valve

Head Loss Due to Pipe Fittings

Pros ConsPlastic bodied ball valves withstand temperatures of up to 100ºC and pressures up to 16 bar making them ideal for most industrial applications.

If you dramatically increase or decrease the flow rate, a linear flow cannot be achieved.

It can usually maintain and regulate high pressure, volume and a high flow effectively.

Becomes fixed in one position, so depending on the medium traveling it could jam.

Generally has a long-service life.  Cannot manage steam under pressure.Ball valves are also easy to use and repair  Available in a range of sizes, predominantly from a ½ inch to 4 inches.

They also come in different body styles including both 2 and 3 way configurations.

Globe Valve

Head Loss Due to Pipe Fittings

Pros ConsWell suited for systems where the fluid is less than 25 gpm.

When part of the globe fails, you often need to rebuild the entire valve (packing washer, seat and gasket)

They can be closed with pressure of 50 pounds psi.

More expensive than the ball valve.

Can manage steam under pressure.  

Available in a range of sizes, predominantly from a ½ inch to 4 inches.

Pros ConsHave low friction loss because there is almost nothing obstructing the flow of the fluid.

They are meant to be fully opened or fully closed, if it is partially open the vibrations caused by the fluid flow could damage the valve.

Cost-effective  Ability to seal tightly, making leakage nearly impossible.

Handles large flows of fluid and a wide range of fluids.

Head Loss Due to Pipe Fittings

• Injury through misuse • Injury from electric

shock• Risk of infection due

to lack of cleanliness• Damage to clothing

SAFETY

Thanks for your attention