PIPE FLOW STIMULATION IN SOLIDWORKS

AIM

To run a pipe flow stimulation with varying inlet Reynolds number of 100, 1000 and 10000.

OBJECTIVES

For the above cases, the following conditions are carried out

• Line probes are placed at 95%, 90% and 85% of the pipe length.
• To compare the normalized velocity profile at each of these locations.
• To normalize the velocity profile by the inlet velocity.

THEORY

The following are the design parameters of the pipe

Parameter	Units mm
Diameter of the pipe	50
Length of the pipe	1000
Thickness of the pipe	2

When a fluid flows through a closed channel such as a pipe, two types of flows , laminar or turbulent flow will occur depending on the velocity and viscosity of the fluid. The velocity of the fluid through a channel is characterized by a dimensionless parameter known as Reynolds number.

LAMINAR FLOW

Laminar flow is a type of flow in which the fluid particles move in well defined path or stream lines where all the stream lines are straight and parallel. The paths of individual fluid particles do not cross the neighbouring particles.

TURBULENT FLOW

In turbulent flow, there is an irregular random movement of fluid in transverse direction of the main flow. This type of flow usually occurs at higher inlet velocity and low viscosity.

REYNOLDS NUMBER

Reynolds number is dimensionless quantity which helps to determine the type of flow in different situations. It depends upon the viscosity of the fluid, density of the fluid and the dimensions of the channel through which the fluid is flowing.

Reynolds number is defined as the ration of inertial forces to the viscous force.

`R_(e )= ρvD⁄μ`

Where

`R_(e )` is the Reynolds number

`v` is the velocity of the fluid in `m⁄s`

`D` is the diameter of the pipe in `m`

`μ` is the dynamic viscosity of the fluid in `Ns⁄m^2`

Laminar flow occurs at low Reynolds number and the turbulent flow occurs at higher Reynolds number.

VELOCITY CALCULATION FOR DIFFERENT REYNOLDS NUMBER

% To calculate the inlet velocities for different conditions

clear all
close all
clc
% Assigining input parameters
Re = [ 100 1000 10000]              % Assigning values for Reynolds number
D = 0.02                            % Assigning the value of diameter in meters
rho = 1.204                         % Density of air in kg/m^3
viscosity = 1.82*10^-5              % Dynamic viscosity of air

% Formula to calculate the inlet velocity
Velocity = (Re*viscosity)/(rho*D) 

The physical properties of air at standard atmospheric pressure is given below

3D MODEL

MODEL WITH LINE PROBES

MESHING

PROCEDURE

• Create a pipe model with 50mm diameter and extrude it to 1000mm.
• Click on Shell icon in the features tab and select both ends of the pipe. This is done to make the pipe hollow. 2mm thickness is specified.
• Line probes are drawn at 95%, 90% and 85% of the pipe length using new sketch.
• Enable Flow Stimulation by selecting Solidworks Add-ins.
• Select the lid command and create lid on both the surface in order to make the pipe water tight.
• Create a new project by selecting the wizard icon.
• Specify the project name and click next.
• In analysis type select Internal flow.
• Select air as the default fluid and select Add and then click Next.
• Specify the initial conditions and click Finish.
• Specify the boundary conditions. Specify inlet velocity in one side of the lid and static pressure in another side of the lid created. Real wall boundary condition is specified by selecting the appropriate face.
• Create an automatic mesh and specify the initial level of mesh.
• Create cut plots and specify the contour as velocity and place them at different line probe position. This is done so that velocity profile at each line probe can be viewed.
• XY Plot is selected for different line probes and select the input parameters as velocity.
• Now Run the stimulation.
• Right click on the respective cut plots to view the results. XY plot obtained in this stimulation can be exported to spreadsheet.

The following are the results obtained from the stimulation

Velocity profile at 850mm line probe

`〖 R〗_(e )100`

`〖 R〗_(e )1000`

`〖 R〗_(e )10000`

Velocity profile at 900mm line probe

`〖 R〗_(e )100`

`〖 R〗_(e )1000`

`〖 R〗_(e )10000`

Velocity profile at 950mm line probe

`〖 R〗_(e )100`

`〖 R〗_(e )1000`

`〖 R〗_(e )10000`

Velocity profile at the inlet

`〖 R〗_(e )100`

`〖 R〗_(e )1000`

`〖 R〗_(e )10000`

XY plot for velocities at `〖 R〗_(e )10`

XY plot for velocities at `〖 R〗_(e )1000`

XY plot for velocities at `〖 R〗_(e )10000`

YOUTUBE LINK

https://youtu.be/uaHz1W1NOkg

PART DRAWINGS

https://drive.google.com/file/d/1YJWJkwmB7E5xw5lO0YVHSEHrcq1T6fWP/view?usp=sharing

https://drive.google.com/file/d/1xVab8zLwZAVhiUI1pzunhvwsIT946yOi/view?usp=sharing

https://drive.google.com/file/d/1fbQfyOOeXf4CZ6tg-9PJf_QrD1vMarUM/view?usp=sharing

RESULTS

A flow stimulation through a pipe is successfully carried out and the velocity profile at different line probes are obtained.

Under practical conditions the flow through a pipe is

• Laminar when `〖 R〗_(e )≤2300`
• Transitional when `〖 2300 ≤R〗_(e )≤4000`
• Turbulent when `〖 R〗_(e ) ≥4000`

The flow changes from laminar to turbulent with increase in velocity indicated by the red region in the velocity profile.

REFERENCES

https://www.slideshare.net/krajesh11111/laminar-turbulent

Wikipedia