AERO-212

EXPERIMENT NO 3
PRESSURE LOSSES IN FITTINGS

Objective: - This experiment measures the pressure loss and friction across pipe length
for different fittings.
Description of the Device: -
This experiment is to be performed using Axial Air Flow apparatus.

Apparatus
 Axial Air Flow apparatus
 Pipe sections
 Fittings (various types)
 Manometer panel
 Hoses for pressure measurement
 Clamps for securing the setup
 Intake pipe bench and fan bench
 Potentiometer for flow rate control
Procedure
1. Setup Preparation
o Position and secure the intake pipe bench and fan bench.
o Lock rollers to prevent movement.
o Connect pipe sections and fittings as per the experiment setup.
o Ensure the experimental plant is connected to the power supply.
2. Installation of Measuring Points
o Install fittings at the inlet of the pipe section.
o Attach the inlet element and mark measuring points.
o Use hoses to connect measuring points to the manometer panel.
o Ensure hoses are free of kinks.
3. Conducting the Experiment
o Turn on the main and fan switches.
o Set the desired flow rate using the potentiometer.
o Record pressures from the manometer tubes.
o Repeat the experiment with different flow rates and fittings.
4. Analysis
o Calculate the dynamic pressure at measuring point 1.
o Determine flow velocity and flow rate.
o Compute pressure loss between measuring points 2 and 3.
o Plot pressure loss against flow rate.
Theory: Pressure Losses in Pipe Fittings
In fluid dynamics and aerodynamics, pressure losses in pipe fittings occur due to
friction, turbulence, and sudden changes in flow direction. These losses directly impact
system efficiency and energy consumption, making their analysis crucial in engineering
applications.
1. Governing Principles
The fundamental equation governing pressure losses in fluid flow is derived from the
Bernoulli equation:

Where:
 P = Pressure (Pa)
 ρ = Density of fluid (kg/m³)
 v = Velocity (m/s)
 g = Acceleration due to gravity (9.81 m/s²)
 h = Height (m)
 hL = Head loss due to friction (m)
Pressure losses can be categorized as:
1. Major Losses – Occur due to friction in long pipe sections.
2. Minor Losses – Occur due to bends, fittings, contractions, and expansions.
The total head loss in the system can be approximated using:

Where:
 f = Darcy-Weisbach friction factor (determined experimentally)
 L = Length of pipe (m)
 D = Diameter of pipe (m)
 K= Loss coefficient of fittings
2. Dynamic and Static Pressure
Pressure in a pipe system consists of:
 Static Pressure : The pressure exerted by the fluid due to its weight.
 Dynamic Pressure: The pressure due to fluid motion,
 The total pressure is given by:

The pressure loss (ΔP) between two measuring points is then:

3. Flow Rate and Velocity Calculation

The velocity of airflow in the pipe is calculated from dynamic pressure:

Since the dynamic pressure is measured at the center of the pipe, the mean velocity is
approximated as 80-88% of the maximum velocity.
The flow rate (QQ) is determined by:
Q=0.8⋅A⋅V
Where:
 A = Cross-sectional area
 d = Diameter of the pipe (m)
4. Graphical Analysis
Two significant relationships are analyzed:
1. Pressure Loss vs Flow Rate This helps visualize how pressure drop increases
with increasing fluid flow.
2. Pressure Loss vs Velocity Shows the effect of velocity on energy dissipation in
the system.
These relationships help determine whether the flow is laminar (Re<2000Re < 2000) or
turbulent (Re>4000Re > 4000)
Experimental Data Table

P total P static P dynamic V (m/s) Q (m³/s) ΔP (Pa)

173 169 4 8 0.012 29.4

169 164 5 8.94 0.014 36.71

164 156 8 11.31 0.017 58.76

158 146 12 13.85 0.021 88.24

149 134 15 15.49 0.024 110.22

140 124 16 16.005 0.025 117.67

Graphs

1) Pressure loss against flow rate

2) Pressure loss against velocity

Safety Precautions
 Know the locations of safety showers, eye wash stations, and fire extinguishers.
 Be aware of emergency exit routes.
 Avoid distractions or sudden movements in the lab.
 Use equipment only for its designated purpose.
 Identify potential hazards before starting the experiment.
 Avoid working alone, especially with hazardous procedures.
 Regularly inspect equipment for wear and deterioration.
 Follow proper waste disposal procedures.
 Avoid wearing jewelry in the lab due to safety hazards.
Critical Analysis
A/C RABIE YOUNUS: Rabie exhibited a strong grasp of fluid dynamics through his
analysis of the pressure loss vs. flow rate graph. He keenly observed the nonlinear
relationship between flow rate and pressure drop, emphasizing how fittings contribute to
increased resistance. His detailed breakdown of the influence of turbulence highlighted
an understanding of how higher flow rates exacerbate energy losses within the system.
His ability to link experimental trends to theoretical concepts, particularly the effect of
fittings on boundary layers and velocity distribution, demonstrated his depth of analytical
thinking. His structured approach helped refine interpretations and solidify the
understanding of how pressure losses evolve with increasing flow rates.
A/C SHAHEER AHMED: Shaheer focused on the velocity vs. pressure loss graph,
offering a comprehensive evaluation of how increasing velocity impacts frictional losses.
His insights into boundary layer formation provided a foundation for understanding how
pipe fittings disrupt flow uniformity, leading to variations in pressure loss. He noted that
at higher velocities, turbulent effects intensify, which correlates well with the observed
steep rise in pressure loss values. His graphical interpretations were meticulous,
highlighting key turning points where resistance drastically increased. By linking his
observations to key fluid mechanics principles, he demonstrated both precision and
depth in assessing experimental results. His contribution significantly enhanced the
group’s understanding of how velocity gradients shape pressure dynamics.
A/C WAJEEH AHMED: Wajeeh displayed a methodical approach in analyzing the
differential pressure values, carefully assessing the growing dynamic pressure and its
relation to energy losses within pipe fittings. He systematically compared experimental
results with theoretical expectations, ensuring alignment between measured values and
predicted trends. His exploration of factors that might have influenced deviations—
including potential measurement errors or minor inconsistencies in fittings—showcased
his meticulous attention to experimental integrity. By emphasizing the significance of
dynamic pressure fluctuations across different fittings, he reinforced the importance of
understanding localized losses in fluid systems. His ability to bridge theoretical
principles with practical findings demonstrated his analytical acumen.
A/C SHIRJEEL ZIA: Shirjeel took a detail-oriented approach to evaluating the reliability
of the experimental setup. His focus on instrumentation accuracy and controlled
conditions contributed significantly to reducing systematic errors. He critically assessed
potential measurement inconsistencies, ensuring proper calibration of the manometer
and verifying hose connections to minimize disturbances. His considerations extended
beyond the numerical analysis—he emphasized the importance of procedural accuracy
and its role in producing valid results. By identifying sources of experimental uncertainty,
he played an essential role in refining the precision of recorded data, ensuring that
trends observed in the graphs were genuinely representative of fluid behavior.
G/C SAUD: Saud provided an insightful perspective on the broader implications of the
experiment, particularly its relevance to aerospace engineering applications. His
observations highlighted how different fittings impact flow efficiency, which is crucial in
designing fluid transport systems for aircraft and propulsion units. He connected the
experimental results to practical considerations, such as optimizing pipe configurations
for minimizing energy losses in real-world systems. His discussion underscored the
necessity of balancing flow rate efficiency with pressure control, ensuring that fittings
are carefully selected for specific engineering needs. By translating raw data into a
meaningful engineering context, he enriched the group's understanding of the
experiment’s significance beyond the laboratory.
A/C MUHAMMAD ANAS: Anas showcased excellent pattern recognition skills,
identifying distinct trends in pressure loss as flow rate increased. His ability to compare
theoretical expectations with empirical results reinforced the credibility of experimental
findings. He emphasized the underlying mathematical derivations, ensuring that the
calculations of flow velocity and pressure differentials remained consistent with fluid
mechanics principles. His approach was meticulous, incorporating structured
methodology to validate data accuracy. By drawing connections between observed
results and governing equations, he effectively demonstrated the importance of
quantitative validation in experimental fluid dynamics.
A/C SHEROZ: Sheroz presented a thorough examination of the flow characteristics
observed throughout the experiment. His focus on differentiating laminar and turbulent
regimes within the pipe sections was particularly valuable. He emphasized the transition
zones where fittings significantly altered flow behavior, demonstrating his ability to
assess localized effects on fluid motion. His critical analysis extended beyond the
immediate results, linking pressure losses to broader fluid mechanics concepts such as
drag and energy dissipation. His ability to contextualize findings within real-world
scenarios provided depth to the group's discussion, reinforcing the technical relevance
of the experiment.

Conclusion
The experiment evaluates how different fittings affect pressure losses and flow
characteristics. By analyzing static and dynamic pressure variations, engineers optimize
piping systems for minimal energy loss and enhanced efficiency.