Simulation of a Mixing efficiency through a T- Junction using ANSYS fluent
In order to understand the importance of Turbulence and Thermal mixing in a T-Junction, two different cases are investigated and the results are compared. in case 1 the hot inlet for air at a temperature of 360C and velocity is 3 m/s and from another inlet, we have a cold inlet for air which is at a temperature of 190C and velocity is 6m/s, The result is measured at the outlet. in case 2 all the parameters are the same except the distance between the inlet and the outlet changes in both the cases as shown in the fig.
The short mixing tee model
The long mixing tee model
Case 1:
i) short mixing tee with a hot inlet velocity of 3m/s
Moment ratio 2
since the momentum ratio = cold inlet velocity/hot inlet velocity,
thus the cold inlet velocity becomes 6 m/s.
The simulation is performed on the above short tee model with the parameters specified and the results are as follows.
the meshed model
Area-Weighted Average of temperature
The standard deviation of the temperature
Residuals
Temperature contour
Velocity contour
ii) short mixing tee with a hot inlet velocity of 3m/s
Moment ratio 4
since the momentum ratio = cold inlet velocity/hot inlet velocity,
thus the cold inlet velocity becomes 12 m/s.
Area-Weighted Average of temperature
The standard deviation of the temperature
Residuals
Temperature contour
velocity contour
Case 2:
i) Long mixing tee with a hot inlet velocity of 3m/s
Moment ratio 2
since the momentum ratio = cold inlet velocity/hot inlet velocity,
thus the cold inlet velocity becomes 6 m/s.
The long mixing tee meshed model
Area-Weighted Average of temperature
The standard deviation of the temperature
Residuals
Temperature contour
Velocity contour
ii) Long mixing tee with a hot inlet velocity of 3m/s
Moment ratio 4
since the momentum ratio = cold inlet velocity/hot inlet velocity,
thus the cold inlet velocity becomes 12 m/s.
Area weighted average of temperature
The standard deviation of temperature
Residuals
Temperature contour
velocity contour
No. of Nodes/Elements Outlet temperature standard deviation No. of iterations
case 1
i) 2887/13014 30.25 1.7 150
ii) 2887/13014 27 1 150
Case 2
i) 4017/18180 30.2 1.4 150
ii) 4017/18180 27 1 150
conclusion: The above simulation results conclude that if the velocity of the inlet cold air increases the outlet temperature decreases. The long mixing tee gives better mixing characteristics than the short one.