Pipe Flow Simualtion

Aim:To do a static analysis of pipe flow at different probe length and compare the velocities.

Introduction:Pipe flow, a branch of hydraulics and fluid mechanics, is a type of liquid flow within a closed conduit (conduit in the sense of a means of containment). The other type of flow within a conduit is open channel flow. These two types of flow are similar in many ways, but differ in one important aspect. Pipe flow does not have a free surface which is found in open-channel flow. Pipe flow, being confined within closed conduit, does not exert direct atmospheric pressure, but does exert hydraulic pressure on the conduit.

Reynolds No.:The Reynolds number (Re) is an important dimensionless quantity in fluid mechanics used to help predict flow patterns in different fluid flow situations. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (eddy currents).

The Reynolds number is defined as

where:

• ρ is the density of the fluid (SI units: kg/m³)
• u is the flow speed (m/s)
• D is the diameter of the tube (m)
• μ is the dynamic viscosity of the fluid (Pa·s or N·s/m² or kg/(m·s))
• ν is the kinematic viscosity of the fluid (m²/s).

Problem Statement: Run a pipe flow simulation with an inlet Reynolds number of 100,1000 and 10,000.

For each of these cases do the following

1. Place line probes at 95%, 90% and 85% of the pipe length.

2. Compare the normalized velocity profile at each of these locations

3. Normalize the velocity profile by the inlet velocity.

Model of pipe:First of all a pipe is made in SOLIDWORKS2018 with the unit system 'MMGS'.

Dimensions: Diameter:40mm

Extruded Length:1000mm

Shell:1mm

As Reynolds No. is given like 100,1000,10000.The velocity corresponding to this can be calculated using the formula:

Velocity at 100:0.0022316m/s

Velocity at 1000:0.022316m/s

Velocity at 10000:0.22316m/s

Probe length is provided at 950mm,900mm,850mm from the inlet.

Meshed Model:In x-direction it is set to 10

In y-direction it is set to 10

In z-direction it is set to 50

Simulation Condition: Common for all cases:

Inputs	Values
Analysis Type	Internal flow(static)
Fluid	Water
Global Mesh Level	4

Boundary Conditions:At the inlet of the pipe lid inlet velocity is set as obtained from the Reynolds No.At the outlet lid static pressure is applied.And the wall is set to real wall.

Procedure:1.First the pipe is made on SOLIDWORKS 2018 with unit system 'MMGS'.

2.Then in flow simulation lid is applied on both side of pipe.

3.Under the new study boundary conditions are applied and computational domain is setup.

4.We have to compare velocities so with the XY plot option velocity in all cases is compared.

Result:For Reynolds No. 100 (i.e. at velocity .0022316m/s):

At 85% probe length velocity cut plot:

At 90% probe length velocity cut plot:

At 95% probe length velocity cut plot:

For Reynolds No. 1000 (i.e. at velocity .022316m/s):

At 85% probe length velocity cut plot:

At 90% probe length velocity cut plot:

At 95% probe length velocity cut plot:

For Reynolds No. 10000 (i.e. at velocity .22316m/s):

At 85% probe length velocity cut plot:

At 90% probe length velocity cut plot:

At 95% probe length velocity cut plot:

Conclusion:At Reynolds No. 100 the velocities of all probe length is compared and the plot is:

We can see that at all probe length the velocity is similar.

At Reynolds No. 1000 the velocities of all probe length is compared and the plot is:

In this case also the velocities are similar for all probe length.

At Reynolds No. 10000 the velocities of all probe length is compared and the plot is:

There is little bit variation we can see but almost it is similar.