Pipe Hydraulics Demystified: A Step-by-Step Guide to Assessing Head Loss Coefficient in Sudden Contraction Scenarios

Aim:

This experiment aims to determine the head loss coefficient due to sudden contraction in pipe hydraulics.

Theory:

Sudden contractions in pipes increase fluid velocity and decrease pressure by converting potential energy into kinetic energy Pipe Hydraulics

We define the head loss coefficient due to a sudden contraction as the ratio between the head loss and the velocity head of the fluid. Denoted by K, it quantifies the relationship between these two parameters.

Apparatus and Material Required:

The apparatus required for this experiment includes:

1. A test rig consisting of a sudden contraction in a pipe with a diameter of D1 connected to a pipe of diameter D2.
2. A pump circulates water through the pipe.
3. A manometer to measure the pressure drop across the sudden contraction.
4. A flowmeter to measure the flow rate of water.
5. A stopwatch to measure the time taken for a specific volume of water to pass through the pipe.

Procedure:

1. Set up the apparatus.
2. The flow meter is set to zero.
3. Switch on the pump and adjust the flow rate to the desired value using a control valve.
4. The flow rate is measured using the flow meter.
5. Measure the pressure drop across the sudden contraction using the manometer.
6. Measure the time taken to pass a specific volume of water through the pipe using a stopwatch.
7. Steps 3-6 are repeated for different flow rates.

Result:

The head loss coefficient K is calculated using the following formula:

K = (h/L) x (D2/D1)^2 x (1/(V^2/2g))

where h – the pressure drop across the sudden contraction,

L –  the length of the sudden contraction, 

D1 – the diameter of the pipe before the contraction,

D2 –  the diameter of the pipe after the contraction,

V – is the velocity of the fluid, and g is the acceleration due to gravity.

Precautions:

1. Before starting the experiment, make sure to properly set up the apparatus.
2. Measure the flow rate accurately using the flow meter.
3. Measure the pressure drop across the sudden contraction accurately using the manometer.
4. Measure the time taken for a specific volume of water to pass through the pipe accurately using a stopwatch.
5. Use clean water to avoid any obstruction in the pipe.
6. Ensure that the pipe is straight before the contraction and after the contraction.

Conclusion:

The head loss coefficient due to a sudden contraction plays a crucial role in fluid mechanics. It serves as an essential parameter that significantly influences various aspects of fluid flow behavior. By quantifying the impact of sudden contractions,

Its determination is fundamental for understanding the energy transformations and pressure variations that occur during fluid flow through sudden contractions. this coefficient enables engineers and researchers to accurately predict and analyze head loss effects in pipe systems.

The experiment conducted in this report has provided a means to determine the value of K. The results obtained can be used to design piping systems and to calculate the

energy losses in the flow of fluids through pipes with sudden contractions. The value of K depends on the geometry of the sudden contraction and the flow rate of the fluid.