Flow simulation in house piping system
Objective
1) To run a pipe flow simulation with an inlet Reynolds number of 100,1000 and 10,000.
2)Placing line probes at 95%, 90% and 85% of the pipe length.
3)Comparing the normalized velocity profile at each of these locations.
Assumptions :
1) The pipe used for simulation is a PVC 1/2 in pipe[1] of length 2ft(609.6mm). Having internal dia of 0.608 in (15.4432mm)and external diameter of 0.84 in (21.336mm).It is assumed that pipe is smooth having no roughness.
2) The pipe is having static pressure of 101325 pa.
3) The fluid flowing in pipe is water having dynamic viscosity of 1.002 centipoise or 10^-3 ns/m2 at 293 k and water is having density of 1000 kg/m3
Calulations:
Calculation of inlet velocity for flow having 100 reynolds number
100= 1000*u*(15.4432*10^-3)/( 10^-3)
u= 0.006475 m/s
Calculation of inlet velocity for flow having 1000 reynolds number
1000= 1000*u*(15.4432*10^-3)/( 10^-3)
u= 0.06475 m/s
Calculation of inlet velocity for flow having 10000 reynolds number
10000= 1000*u*(15.4432*10^-3)/( 10^-3)
u= 0.6475 m/s
Methodology
A pipe of relevant size is created in CAD and flow simulation is carried out on the model. Folowing boundary conditions are applied
1) Inlet velocity is given to one of the pipe lids
2) Static pressure is given on other link
3) wall is considered real.
A parametric study is caried to compare results and effect of velocity on pipe and various results were plot.A animation is also caried out to see velocity profile at 10000 reynolds no.
Results
For reynolds No of 100
Fig1. Velocity profile at 85% of length
Fig2. Velocity profile at 90% of length
Fig3. Velocity profile at 95% of length
For reynolds No of 1000
Fig 4. Velocity profile at 85% of length
Fig5. Velocity profile at 90% of length
Fig6. Velocity profile at 95% of length
For reynolds No of 10000
Fig7. Velocity profile at 85% of length
Fig8. Velocity profile at 90% of length
Fig9. Velocity profile at 95% of length
Graphs
Graph1. Velocity profile for different reynolds No at 85 % of length
Graph2. Velocity profile for different reynolds No at 90 % of length
Graph3. Velocity profile for different reynolds No at 95 % of length
Graph4. Velocity comparison at 85% 90% and 95% of length for different reynolds no
Graph5. Velocity profile for re=100 (zoomed)
Graph6. Velocity profile for re=1000 (zoomed)
Graph7. Velocity profile for re=10000(zoomed)
Animations
Animation Showing velocity profile in circular cut section
Animation Showing velocity profile in vertical cut section
Conclusion
1) High reynolds number gives high inlet velocity if other parameters are constant.
2) For re 10000 velocity profile remains saturated/ constant for certain distance along diameter .The shape of velocity is trapezoidal. It has a maximum speed is 0.89 m/s.And this result is valid for turbulent flow.
3) For re 1000 velocity profile is parabolic in shape and it reaches maximum velocity at centre of circular cross section of pipe It has a maximum speed is 0.12 m/s. This result is valid for laminar flow.
4) For re 100 velocity profile is parabolic in shape and it reaches maximum velocity at centre of circular cross section of pipe. It has a maximum speed is 0.01m/s which is low This result is valid for laminar flow.
5) Velocity profile comparison at 85% , 90% and 95% of length yields same result for laminar flow.
6)Velocity profile comparison at 85% , 90% and 95% of length show there is a slight increase in maximum velocity.
7) From animation variation of velocity profile along length and diameter can be seen.
References
2)https://www.redfin.com/blog/2015/06/does-this-house-have-good-water-pressure.html
3)https://www.engineeringtoolbox.com/flow-velocity-water-pipes-d_385.html
4)https://www.engineersedge.com/physics/water__density_viscosity_specific_weight_13146.htm