Flow Simulation through a hollow pipe
I performed a flow simulation on a pipe of 0.04 m outer diameter and a wall thickness of 0.001m at room temperature of 20 C and the length of the pipe was 1 m. The simulation consisted of three cases wherein the reynolds number at the inlet were taken as 100, 1000 & 10000 respectively and the fluid taken was water. The flow enters the pipe from the left and exits from the outlet at the right. At the outlet side there are 3 line probes at a distance of 85%, 90% & 95% of the total length of the pipe. The velocities are compared at these probes in each of the three cases.
Firstly we needed to find out the velocity of the flow of water with the help of reynolds number. For that pupose we use the formula :
`V=(Re*mu)/(rho*Dh)`
That is,
V=(Re⋅μ)/(ρ⋅Dh)
where,
V = Inlet Velocity of the Fluid, m/s
Re = Reynolds Number
μ = Dynamic Viscosity of water at 20 C, i.e 1.002 x 10^-3 N s/m^2
ρ = Density of water at 20 C, i.e 998 kg/m^3
Dh = Hydraulic Diameter/ Internel Diameter of the pipe, i.e 0.038 m
Calculations to find the Velocity at inlet, (m/s)
At Re= 100
V=(Re⋅μ)/(ρ⋅Dh)
=`(100*1.002*10^-3)/(998*0.038)`
=0.00264 m/s
Similarly,
For Re= 1000, Velocity= 0.0264 m/s
For Re= 10,000, Velocity= 0.264 m/s.
Basic common settings.
In the first and the second case the flow type is taken to be laminar as the reynolds number is less than 2000, whereas in the third case the type of flow is turbulent as the reynolds number is 10,000. The mesh size taken is X=10, Y=10 & Z=50, which is common for all the three cases. The velocity for the plots is set to Global maximum and minimum and the boundary conditions are set to real wall and static pressure at the outlet.
CASE 1: When the Reynolds number is 100 (Laminar Flow)
The figure shows the cut plot of the flow of water in a pipe of hydraulic diameter 0.038m with a reynolds number 100 and a calculated velocity of 0.00264 m/s from left to right. The flow is laminar as the reynolds number is less than 2000. The contours at the inlet and outlet of the flow is shown in the cut plots below respectively with the colour blue representing the minimum velocity of 0 m/s and red representing a global maximum velocity of 0.005 m/s.
The XY plot along with the comparison and variations in the velocities is given later in the article in an excel sheet.
CASE 2: When the Reynolds number is 1000 (Laminar Flow)
The figure shows the cut plot of the flow of water in a pipe of hydraulic diameter 0.038m with a reynolds number 1000 and a calculated velocity of 0.0264 m/s from left to right. The flow is laminar as the reynolds number is less than 2000. The contours at the inlet and outlet of the flow is shown in the cut plots below respectively with the colour blue representing the minimum velocity of 0 m/s and red representing a global maximum velocity of 0.047 m/s.
The XY plot along with the comparison and variations in the velocities is given later in the article in an excel sheet.
CASE 3: When the Reynolds number is 10,000 (Turbulent Flow)
The figure shows the cut plot of the flow of water in a pipe of hydraulic diameter 0.038m with a reynolds number 10,000 and a calculated velocity of 0.264 m/s from left to right. The flow is turbulent as the reynolds number is greater than 4000. The contours at the inlet and outlet of the flow is shown in the cut plots below respectively with the colour blue representing the minimum velocity and red representing the global maximum velocity of 0.334 m/s.
The XY plot along with the comparison and variations in the velocities is given later in the article in an excel sheet.
COMPARISON OF THE NORMALIZED VELOCITIES ALONG WITH THE XY PLOTS.
The link for the comparison sheet between the velocities of reynolds number 100, 1000 & 10000 with line probes at 85%, 90% & 95% along with the XY Plots is given below :
https://drive.google.com/file/d/1uNZp6cYxGeAJgMLYLSbvzY4IgQNZMnqP/view?usp=sharing