Pipe Flow Simulation with varied Reynolds numbers using Solidworks

AIM: To perform a pipe flow simulation on a pipe with variable Reynolds numbers using Solidworks

OBJECTIVE:

1. To run a pipe flow simulation for the following inlet Reynolds numbers:
   
   • 100
   • 1000
   • 10000
2. To generate plots by placing probes at the following lengths:
   • 95% - 0.05 m from the outlet
   • 90% - 0.10 m from the outlet
   • 85% - 0.15 m from the outlet
3. To compare the normalized velocity profiles at all theses locations and then normalize the velocity profile by the inlet velocity.

INTRODUCTION

FLUID FLOW SIMULATIONS

Fluid flow simulations are performed inorder to create a working design at maximum efficiency, inorder to manufacture real life components.It allows us to design pipes and simulate their performance in a virtual environment.This allows the designer to model the fluid’s behavior at every stage in the process and accurately predict how it will react during real life situations. It reduces the time considerably and reduces cost considerably.This is a major consideration when it comes to designing new products and it places a great deal of limitations on the designer. The science of fluid dynamics is incredibly complex and the chances of error are high. This means that the process can be an iterative one, with many repetitions and consequent impacts on the time and cost of development. With fluid flow simulation software, the entire process is much more streamlined.

THEORY

Reynolds Number

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 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. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow.

Classification of Flows

a) LAMINAR FLOW: in this type of flow Reynolds number is less than 2100. The streamline lines are smooth and regular and a fluid element moves smoothly along streamline in a layered manner.

b) TURBULENT FLOW: in this type of flow Reynolds number is greater than 4000. The streamlines break up and fluid element moving in a random, irregular, and tortuous fashion.

Equations used

Reynolds number `Re`

`Re = (rho v L)/ mu = (vL)/(nu)`

where

`rho`- density of the fluid (kg/m³)

`v` - velocity of the fluid with respect to the object (m/s)

`L` - length of the pipe (m)

`mu`-dynamic viscosity of the fluid (Pa s)

`nu` - kinematic viscosity of the fluid (m²/s)

MODEL OF THE PIPE

PROCEDURE

• Create a model of the pipe with the input parameters given below.
• Create probes on the sketch at 0.05, 0.10 and 0.15 m from the outlet.
• Select lids on the inlet and outlet
• Open Fluid Simulation in addins and select the neccesary options from the wizard
• Imput the following boundary conditions:
  • Inlet velocity = 0.00185 m/s when R=100
  • = 0.0185 m/s when R=1000
  • = 0.185 m/s when R=10,000
  • Static pressure = 101325 Pa
  • Temperature = 293.2 K
  • Wall type = Real wall
• Make cut plots across the probes and run the simualtion. Then perform a parametric study and generate plots for each conditions

INPUT PARAMETERS

• Length: 1m
• Outer diameter:0.050 m
• Internal diameter:0.048 m
• Fluid: Water
• Density of water: 1000 kg/m³
• Dynamic viscosity: 8.9×10−4 Pa s

CALCULATIONS

Sl.No	Reynolds Number	Velocity(m/s)
1.	100	0.00185
2.	1000	0.0185
3.	10000	0.185

RESULTS

PLOTS AND GRAPHS

1. Re=100 , v=0.00185 m/s

a. Probe at 95%

b. Probe at 90%

c. Probe at 85%

Velocity variation when Re=100 and v=0.00185 m/s:

2. Re=1000 , v=0.0185 m/s

a. Probe at 95%

b. Probe at 90%

c. Probe at 85%

Velocity Variation when Re=1000 and v=0.0185 m/s:

3. Re=10000 , v=0.185 m/s

a. Probe at 95%

b. Probe at 90%

c. Probe at 85%

Velocity variation when Re=10000 and v=0.185 m/s:

Normalized Velocity:

OBSERVATIONS

• There are variations in flow velocity as the fluid slowly progresses towards the static pressure outlet.
• Velocity of the fluids is dependent on its Reynolds number

CONCLUSION

The velocity profile for the Reynolds numbers 100,1000 and 10000 at 95%,90% and 85% length of pipe are ploted.