Pipe Flow Simulation

AIM:

To do a pipe flow simulation with line probes using SOLIDWORKS

OBJECTIVES:

To do pipe flow simulation with an inlet Reynolds number of 100, 1000, 10000 by placing line probes at 95%, 90%, and 85% of the pipe length.

Compare the normalized velocity profile at each of these locations.

Normalize the velocity profile by the inlet profile.

THEORY:

FLUID: A fluid is any substance that flows or deforms under applied shear stress or, the substance which have the tendency to flow is called as fluid.

LAMINAR AND TURBULENT FLUID FLOW:

The laminar flow is defined as the type of flow in which the fluid particles move along well-defined paths or streamline and all the streamlines are straight and parallel.

Thus, the particles move in laminas or layers gliding smoothly over the adjacent layer. This type of fluid is also called as streamline flow or viscous flow.

The turbulent flow is defined as the type of flow in which the fluid particles move in a zig-zag way, eddies formation takes place which is responsible for high energy loss.

For pipe flow, the type of flow is determined by a non-dimensional number called the Reynolds number.

With respect to laminar and turbulent flow regimes:

Laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid motion

Turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic eddies, vortices and other flow instabilities.

Reynolds Number: It is a dimensionless value which is used to represent whether the fluid is laminar or turbulent. It is the ratio of inertial force to viscous force.

It is expressed by, `Re =ρu D/μ=u D/v`

Where, `ρ` is the density of the fluid; `u` is the flow speed; `D` is the diameter of the tube; `μ` is the dynamic viscosity of the fluid; `v` is the kinematic viscosity of the fluid.

Reynolds Number formula is used to determine the velocity or, diameter or, viscosity of the fluid.

PROCEDURE:

• Create a 3D model of a pipe of outer diameter 0.07 m, length 0.5 m, and thickness 0.001 m which means inner diameter 0.068 m. Draw three lines i.e. at 0.475 m, 0.450 m, and 0.425 m as different sketches, these are the line probes.

• Now calculate the value of inlet velocity for each Reynolds number with 0.068 m as the diameter (D). Here water is considered as the flowing fluid which has a Dynamic viscosity `μ=8.90×10^(-4)` Pa.s, Density `ρ=1000 (kg)/m^3`

Re = 100	Re = 1000	Re = 10000
u = 0.00130 m/s	u = 0.0130 m/s	u = 0.130 m/s

• Now create lids, to get the option of create lid click on flow simulation tab.
• Now click on “New” in the flow simulation tab and then start with the new project.
• Now give “Boundary Conditions” starting with the “Inlet Velocity” at one of the lid and then give the “Wall” condition, then provide with the “pressure” at outlet. All of the face for these conditions should be selected by right clicking and the select “select other” and then select the “face @ lid” for inlet velocity and pressure condition and for wall condition “shell”.
• Now create a mesh by right clicking on “Global Mesh” and then “Manual” for customizing the number of cells.

• Now create cut plots to visualize results by right clicking on “Results” and the on “Cut Plot”. For analyzing the velocity at different lengths and also for comparing the velocities at different lengths.
• Now for creating a parametric study right click on your project name and then click on “New Parametric Study”.
• Now give input variables that you want to change for your analysis. Here I have selected only velocity from “Boundary Conditions”
• Now for output parameters select all the plots.
• Now in “Scenario” copy the “Design Point” and then paste it two times and now change the velocity in those two Design Points.
• Now click on “Run”.

RESULTS:

CUT PLOTS AT 85 % OF LENGTH AND REYNOLDS NUMBER 100, 1000, AND 10000

CUT PLOTS AT 90 % OF LENGTH AND REYNOLDS NUMBER 100, 1000, AND 10000

CUT PLOTS AT 95 % OF LENGTH AND REYNOLDS NUMBER 100, 1000, AND 10000

VERTICAL CUT PLOTS AT REYNOLDS NUMBER 100, 1000, AND 10000

VELOCITY AT 85 % OF LENGTH

VELOCITY AT 90 % OF LENGTH

VELOCITY AT 95 % OF LENGTH

VELOCITY COMPARISON

NORMALIZED VELOCITY AT REYNOLDS NUMBER 100

NORMALIZED VELOCITY AT REYNOLDS NUMBER 1000

NORMALIZED VELOCITY AT REYNOLDS NUMBER 10,000

CONCLUSIONS:

We can see that as the Reynolds number increases the velocity profile also changes as the flow from being a lamina changes to turbulent. The velocity at the center of the pipe is maximum and at the boundary it is minimum because of friction experienced at the wall of the pipe.