Pipe flow simulation with line probes( parametric study)

Inroduction:

In this project I have tried to simulate the pipe flow through a normal pipe using solidworks CFD simulation. In the challenge the following things were asked to accomplish:

• We have to perform the simulation using line probes .
• we have to use the following reynolds no. 100,1000,10000.
• we have to place line probes at 95%, 90% & 85%of the pipe length.
• we have to normalize the velocity according to the inlet velocity.

The geometry that I modeled had the following dimensions:

• pipe length: 1000mm=1m
• pipe diameter: 40 mm
• pipe thickness: 3mm

*** I chose to go with water @ 0°C

Interpretation of data:

At first we have to go with line probes, we use this to get better study results at specific points instead of getting a overall result. This gives our resuls a more techinal point as we need to check effect of flow at different points or crucial points raather than as a whole.

There were specific reynolds no. provided to us in the challenge. But we had the freedom to change other parameters like pipe diameter and temperature ( i have taken water @0°C). How ever the velocity had to be found by the relation between reynolds no. and velocity in a pipe flow. It is described as :

Reynolds no. = ρ⋅v⋅d/μ

ρ=density of fluid

v= velocity of fluid

d= Internal diameter of pipe

μ= dynamic viscocity of fluid

Using this realtion the velocites at given reynolds no. came out to be:

• Reynolds no. = 100 , Velocity 1 = 4.97857435⋅10^−3 m/s
• Reynolds no. = 1000 , Velocity 2 = 4.97857435⋅10^−2 m/s
• Reynolds no. =10000 , Velocity 3 = 4.97857435⋅10^−1 m/s

For placing the line probes at specific intervals :

• 95% from inlet = 950 mm from inlet
• 90% from inlet = 900mm from inlet
• 85% from inlet = 850 mm from inlet

For normalisation i had to compare the velocities at different line probes to get the idea about effect of flow at those line probes as compared to one another at different points/ line probes.

For general mesh properties I went with the following:

• Number of cells per X=20
• Number of cells per Y=20
• Number of cells per Z=100

The design points are at following velocities:

• Design point 1: Velocity 1 = 4.97857435⋅10^−3 m/s
• Design point 2: Velocity 2 = 4.97857435⋅10^−2 m/s
• Design point 3: Velocity 3 = 4.97857435⋅10^−1 m/s

Result:

• velocities at different points.
• 1st graph is at line probe 850mm from inlet
• 2nd graph is at line probe 900mm from inlet
• 3rd graph is at line probe 950mm from inlet

In all the three graphs we dont see any notable difference at design point 1 which is in red and at Velocity 1 = 4.97857435⋅10^−3 m/s. if we move further at designt point 2 which is at Velocity 2 = 4.97857435⋅10^−2 m/s we notice very minute difference almost negligible. But if we look at design point 3 which is at Velocity 3 = 4.97857435⋅10^−1 m/s we see significant difference. Let's look at the following normalisation graph.

In the Normalization graph we can clearly see the difference at design point 3 where as at other design points the diffecence is not so significant or not so noticable. If we looks carefully at the tip of the graph at design point 3 we get there is different effect at different inlet velocities. This is pattern of all the graphs is due to change in distance between the line probes which helps to see the difference in velocity at those points through these graphs. In the normalisation graph we can see the change in velocity with slight change in length at design point 3.

Let's look at the cut plots at the outlet at different vecolities:

• 1st cut plot is at Velocity 1 = 4.97857435⋅10^−3 m/s (design point 1)
• 2nd cut plot is at Velocity 2 = 4.97857435⋅10^−2 m/s (design point 2)
• 3rd cut plot is at Velocity 3 = 4.97857435⋅10^−1 m/s (design point 3)

Design point 1

Design point 2

Design Point 3

In the above cut plots we can see the variation of velocity at different points namely from center of the pipe towards the wall of the pipe. In all the cut plots the common observation is that the velocity is maximum at the center of the pipe and then it goes on decreasing towards te walls. In the first cut plot at design point 1 we can see more variation of velocity in the contour as compared to other plots. in the third cut plot we can see that the velocity is mostly on the higher side in contours.

Conclusion:

In the above study we get the idea that, at different vecolities we get visible changes by line probe study at differnt distance points. Also, the velocity never remains the same throughout the study it hanges at every point and each direction. So, a through study is always recommended for every point of a fluid carry part/object.