Design and Fabrication of Water Tunnel For Flow Visualization

Project Title

Design and Fabrication of Water Tunnel For Flow Visualization

Project Area of Specialization Mechanical EngineeringProject Summary Water Tunnel:

• A water tunnel is an experimental facility used for testing the hydrodynamic behavior of submerged bodies in flowing water.
• Design and development of water tunnel and efficient embedded system for flow visualization.
• It functions similar to a recirculating wind tunnel, but uses water as the working fluid, and related phenomena are investigated, such as measuring the forces on scale models of submarines or lift and drag on hydrofoils.
• It’s use in checking the behavior over various structures and analyzing the boundary layer process for separation of flow, shedding of vortex etc.
• The principle of operation of the water tunnel resembles the wind tunnel, visualization of flow is easier than wind tunnel due to higher viscosity of water and various kinds of techniques for visualization can be used.
• The purpose of the water tunnel is to obtain uniform and steady speed of flow in the test section.
• The water tunnel can also be utilized for the purpose of education such as fluid mechanics lab activity to learn about different topic taught in the class.
• Vibration analysis done using fast fourier transform (FFT), power spectrum density (PSD), empirical mode decomposition (EMD) along with statistical parameters. 

Components:

1. Pump (10 hp)
2. Divergent (use to decrease the velocity)
3. Flow conditioning system :> Baffles (consists on pipe used to uniform and steady the flow)
4. Convergent (used to chanelize the flow to the test section which is laminar in nature)
5. Test section (here we read the charctistics of specimen) 
6. Outlet (it is just a pipe)
7. Pipes and elbows (Use to circulate the flow in a closed loop).

Velocity range in test section:

For flow visualization 0 to 0.7 m/s

Flow Rate Range:

upto 2200 liter/min

Test Section Cross-section:

9 square inch

Project Objectives Objectives:

1. Design and development of water tunnel and efficient embedded system for flow visualization.
2. Structure stability improvement
3. life improvement of structure
4. vibration analysis of structure (Vibration analysis done using fast fourier transform (FFT), power spectrum density (PSD), empirical mode decomposition (EMD) along with statistical parameters).
5. Lift and drag force on different structure

Project Implementation Method Methodology:

Components and Details:

TEST SECTION:

• Mild steel frame
• LWH: 0.229 x 0.229 x 0.9144 m
• Acrylic glass used for transparent surface
• An open section is made on top surface to allow test specimen to be place in the test section.

Material of Acrylic Glass:
 IUPAC Name: Methyl 2- Methyl Propionate.
 CAS Number: 9011-14.7
 Chemical formula: (C5O2H8) n
 Density :1.18 g/cm3
 Melting point: 160°C

Advantages of Acrylic Glass:
1. Acrylic glass transmits more light than normal glass.
2. The value of thermal conductivity is much higher than the glass.
3. It is easy to clean in order to remove dirt.
4. Acrylic glass has higher impact strength than normal ordinary   glass.
5. It sustains high pressure load

NOZZLE/DIFUSSER:

• Galvanized Iron sheet (1.5 mm)

	Inlet(mm)	Outlet(mm)	Length(mm)
Nozzle	430 x 480	229 x 229	685
Diffuser	229x 229	430 x 480	575

• Made by bending the sheets of iron and has flanges on both sides to couple while assembly.
• The material chosen because it is light weight and corrosion resistant.

BAFLLES:

• Mild steel (Frame) and Plastic pipe of 0.0889 m (0.75 in) used.
• The frame has 4 closed surfaces.
• Plastic pipes have been used as baffles to make the flow laminar.
• The number of pipes were chosen by keeping in mind the its effect on head loss and the Reynold’s No.
• The packing frame is made from wood

Valves Types:

• Manual Valves
• Hydraulic Valves
• Pneumatic Valves
• Motor Valves
• Solenoid Valves
• We’ll be using the manual type valve i.e., Gate Valve

Equipment Used in Condition Monitoring (Vibration Analysis):

• Accelerometer
• Anemometer (Micro controller)
• Flow sensor
• Load cell
• Pitot tube
• Raspberry (Pi 4B 4GB)

 

Nozzle

Diffuser

Benefits of the Project Benefit of the Projects:

Water tunnel is very helpful to study the phenomenon like vortices generation, vortices induce vibrations, shedding, lift and drag forces. Unlike wind tunnel it is very easy and reliable to study these phenomena. We can also use PIV technique to study the flow phenomenon by using high speed cameras. In this project, all the test section wall are kept transparent so that if we use PIV technique, we can easily pass the light from the bottom and record the flow phenomenon in the camera. So, in this way the project is beneficial to study the flow phenomena for BS level and also for MS and Ph.D. level for different research purpose study.

Water tunnel are cheaper to build and operate, and simplified models can be easily modified to suit new testing requirements as a program proceeds. Water tunnels are ideally suited to flow-visualization studies, giving an insight into the physics of the flow. With recent advances in measurement technology, they can now also be used to measure the very small flow-induced loads on models. Using water tunnels, it is possible to simultaneously measure loads and visualize high-quality off-surface flows, so that the loads and images can be correlated directly. Water tunnels are also better suited to modern laser-based flow field-diagnostic methods, such as Particle Image Velocimetry.

It was found that the suitability of water tunnels for testing given models needs to be assessed on a case-by-case basis. Water tunnels will not overcome the need for large-scale, high-precision testing, and are at most marginally useful for producing reliable results in configuration aerodynamics, even in the conceptual design stage. For conventional aircraft testing, such as lift and drag measurements, they compare unfavorably with similar-sized wind tunnels, because of the mismatch in Reynolds numbers. Water tunnels are more of a fundamental research tool than an applied aerodynamics tool. However, they are very useful as a component of a large research program, by focusing the test matrix in large wind tunnels and providing validation for computational-fluid-dynamics analyses of the flow. In problems insensitive to Reynolds number, or where a test Reynolds number is close to that of a full-size vehicle, water tunnels should be regarded as the principal tool of experimental aerodynamics.

Technical Details of Final Deliverable Technical Details of Final Deliverable:

• outlet of pump is 2 inches which is increase to 4 inches so that thrust in the apparatus is to be reduce.
• Diffuser divergence angle kept between 5 - 15 degree. Less than 5, the diffuser is too long and has too much friction while angles greater than 15 cause flow separation, resulting in poor pressure recovery. 
• Fraud number of our project is < 1, i.e., fall in subcritical flow. (Mach number not used in water tunnel)

Fr = 1,   critical flow,

Fr > 1,    supercritical flow (fast rapid flow),

Fr < 1,    subcritical flow (slow / tranquil flow)

• Major and minor head loss are calculated. Major head loss is due to the flow of water in a constant cross section along length while minor losses happen in change in cross section along length as well as in bends. Total head loss calculated in the project is 7.8478 meter.
• The Pump is selected on the basis of the Total Head loss obtained from the Plumbing Subsystem in the Water Tunnel by the Formula:  P= ?gHQ

According to this the required power of the pump is determined to be 3.77 hp without Factor of Safety.

Power=5.66 hp (factor of safety= 1.5)

5hp Pump Flow Rate= 505 LPM

10hp Pump Flow Rate= 2200 LPM

With 5.66 hp power the required flow rate pump was not found in the market so 10 hp pump fulfill both power and flowrate requirements.

• All the calculations of the projects is done in MATLAB by write the codes.

Equipment Used in Condition Monitoring (Vibration Analysis):

• Accelerometer
• Anemometer (Micro controller)
• Flow sensor
• Load cell
• Pitot tube
• Raspberry (Pi 4B 4GB)

Final Deliverable of the Project Hardware SystemCore Industry EducationOther IndustriesCore Technology OthersOther TechnologiesSustainable Development Goals Quality EducationRequired Resources

Elapsed time in (days or weeks or month or quarter) since start of the project	Milestone	Deliverable
Month 1	Fluid Mechanics Revisions and Literature Review	Completed
Month 2	Planning and Sizing of Water Tunnel Components	Completed
Month 3	Calculations & Design using MATLAB	Completed
Month 4	Design Modeling in Solidworks and Scale Model Simulations (ANSYS)	Completed
Month 5	Fabrication & Manufacturing	Completed
Month 6	Verification of Results	Pending
Month 7	Project Report / Thesis Compilation	Pending