Week 1- Mixing Tee

MIXING TEE

Aim: To set up steady-state simulations to compare the mixing effectiveness when hot inlet temperature is 36⁰C & the Cold inlet is at 19⁰C.

1. Case 1
   • Short mixing tee with a hot inlet velocity of 3m/s.
   • Momentum ratio of 2, 4.
2. Case 2
   • Long mixing tee with a hot inlet velocity of 3m/s.
   • Momentum ratio of 2, 4.

Introduction:
Mixing Tee provides the proper mixing of two fluid quantities at certain temperatures to get the desired result of temperature outlet.

Theory: Varying the velocity of cold air at inlet we can get the desired temperature in the room.

Procedure:

Open the geometry in Space claim.

Extract the volume of fluid flow.

Meshing:

Open the geometry in mesh file.

Click on Generate mesh for meshing.

Assign the Name accordingly for faces.

Setup:

Select 'double precession' and start.

Solver

Time : Steady State

Type: Pressure based

Select Energy for Temperature calculation.

K-epsilon model

Case 1: Short mixing tee

Momentum ratio = 2

Cold inlet = 6 m/s.

Hot inlet = 3 m/s.

Velocity contour plot:

Temperature contour plot:

Temprature plot:

Average outlet temperature = 32.886789 C

Momentum ratio = 4

Cold inlet = 12 m/s.

Hot inlet = 3 m/s.

Velocity contour plot:

Temperature contour plot:

Temperature plot:

Average outlet temperature= 31.44728 C

K-Omega :

Case 1:

Momentum ratio = 2

Cold inlet = 6 m/s.

Hot inlet = 3 m/s.

Average outlet temperature: 32.91747 C

Velocity contour plot:

Temperature contour plot:

Momentum ratio = 4

Cold inlet = 12 m/s.

Hot inlet = 3 m/s.

Velocity contour plot:

Temperaure contour plot:

Average outlet temperature: 31.440433 C

Case 2:

The k-epsilon model gives better solution.

Long Mixing tee

Geometry:

Meshing:

Setup:

K-epsilon model

Steady state

Momentum ratio =2

Hot velocity =3 m/s

Cold velocity = 6 m/s

Velocity contour:

Temperatue at outlet= 30.30313 C

Temperature plot:

Temperature contour:

Momentum ratio =4

Hot velocity = 3m/s

Cold velocity = 12m/s

Velocity contour:

Temperature contour:

Outlet average temperature= 27.481109 C

Temperature plot:

Conclusion:

In case of Higher momentum ratio, the outlet temperature decreases.

Achieved the expected results for temperature and velocity.

The outlet temperature is independent of the length of the pipe.