Mixing Efficiency

Objective:

For this challenge, we have created two versions of the mixing tee. One of them is longer than the other.

• Case 1 (60 points)
  • Short mixing tee with a hot inlet velocity of 3m/s
  • Momentum ratio of 2
• Case 2 (60 points)
  • Long mixing tee with a hot inlet velocity of 3m/s
  • Momentum ratio of 2
• Case 3 (60 points)
  • Short mixing with a hot inlet velocity of 3 m/s
  • Momentum ration of 4
  • Momentum ratio = velocity at cold inlet / velocity at hot inlet

Introduction:

The main aim of this project is calculated the outlet Temperature of tee Joint. In this, we are mixing of fluids with two different temperature at y-direction we injected cold fluid at 10 degrees and x-direction injected hot fluid at 25 degrees.

Volume Extract:

In this step, we are Extract the volume using space claim geometry, this is one kind of geometry editing module. why should we do volume extract? This project we are calculated fluid flow inside volume and temperature. so we don't need outer surface of the geometry that's why we are eliminating outer surface using volume extract.

Meshing:

In this step, we are going to divided large geometry into small cells this is call Meshing. Meshing is different types

1)structure Mesh

2)Un structure mesh

Ansys creating an unstructured mesh-like tetrahedral mesh with 0.002 cell size.

Mesh Quality:

Boundary Conditions:

In this step created Boundary condition like Inlet velocity, Temperature, pressure, etc. In this project given two inlets and one outlet.

1) inlet_x

2)inlet_y

3)outlet

4)Wall

Inlet_x defines hot fluid enters into the pipe at 25-degree temperature with 3 m/s velocity and inlet_y defines cold fluid enters at 10-degree temperature and calculated velocity using momentum ratio.

Solving:

Case-1: Short pipe injected hot fluid with 3 m/s and cold fluid 6m/s, for calculating the cold fluid velocity using this formula

This case we are injected hot fluid with 3 m/s and cold fluid 6m/s, for calculating the cold fluid velocity using this formula

`Movementum Ratio = (cold fluid)/(hot fluid)`

`2 = (cold fluid)/3`

cold fluid velocity = 6 m/s

Temperature Counter:

Above figure defines the visualization of two different temperature fluids mixing inside a pipe and calculated outlet temperature.

The plot of Area-weighted Average of Temperature:

The above graph defines the outlet temperature of the pipe when two different temperature of fluid enters into the pipe and mixing together inside a pipe and finally we will get an efficiency of mixing temperatures at the outlet. as seen above the outlet temperature continuously drop down from 22 to 20 degrees and it reached steady-state after 50 iterations convergence.

The plot of Standard deviation of temperature:

The above plot defines the standard deviation of temperature, nothing bus the temperature difference inside a pipe. here, the standard deviation temperature is finally reached 1.7 degrees. the two mixing fluids temperature difference reached 1.7 degrees.

The plot of Residual terms:

The above graph contains many plots, these are calculated in each cell in geometry like Mass transfer, Movement of fluid, Energy plot defines temperature distribution inside pipe and K is the kinetic energy of fluid and epsilon is defines fluctuations inside a pipe.

Case-2: long pipe injected hot fluid with 3 m/s and cold fluid 6m/s, for calculating the cold fluid velocity using this formula

This case we are injected hot fluid with 3 m/s and cold fluid 6m/s, for calculating the cold fluid velocity using this formula

`Movementum Ratio = (cold fluid)/(hot fluid)`

`2 = (cold fluid)/3`

cold fluid velocity = 6 m/s

Temperature Counter:

Above figure defines the visualization of two different temperature fluids mixing inside a long pipe and calculated outlet temperature.

The plot of Temperature:

The above graph defines the outlet temperature of the pipe when two different temperature of fluid enters into the pipe and mixing together inside a pipe and finally we will get an efficiency of mixing temperatures at the outlet. as seen above the outlet temperature continuously drop down from 22 to 20.1 degrees and it reached steady-state after 50 iterations convergence. As we have seen above the plot defines outlet temperature same as the short pipe like case-1. because of the inlet temperatures of the velocity is equal.

The plot of Standard deviation of temperature:

The above plot defines the standard deviation of temperature, nothing bus the temperature difference inside a pipe. here, the standard deviation temperature is finally reached 1.1 degrees. the two mixing fluids temperature difference reached 1.1 degrees.

Residual Terms:

Case-3: Short pipe injected hot fluid with 3 m/s and cold fluid 12m/s, for calculating the cold fluid velocity using this formula

This case we are injected hot fluid with 3 m/s and cold fluid 12m/s, for calculating the cold fluid velocity using this formula

`Movementum Ratio = (cold fluid)/(hot fluid)`

`4 = (cold fluid)/3`

`cold fluid velocity = 12 m/s`

Temperature counter:

The plot of Temperature:

The above graph defines the outlet temperature of the pipe when two different temperature of fluid enters into the pipe and mixing together inside a pipe and finally we will get an efficiency of mixing temperatures at the outlet. as seen above the outlet temperature continuously drop down from 22 to 17.5 degrees and it reached steady-state after 50 iterations convergence.

The plot of Standard deviation of temperature:

The above plot defines the standard deviation of temperature, nothing bus the temperature difference inside a pipe. here, the standard deviation temperature is finally reached 1-degrees. the two mixing fluids temperature difference reached 1-degrees.

Conclusion:

1)Above comparison between three cases When the velocity increases the mixing efficiency increases that we can see in the third case.

2)Comparison between the first and second case the mixing efficiency increases when the length of the pipe increases.

3)The cell count increases and simulation time increases when the length of the pipe increases.

4)Comparing convergence of the solution is very quick in the first case because the velocity of the fluid is low.