Week 1- Mixing Tee
SIMULATION OF MIXING TEE
AIM:
To simulate flow through a mixing tee with different geometry configurations (short and long) and to compare the mixing effectiveness when hot inlet temperature is 360C & the Cold inlet temperature is at 190C,with the hot inlet velocity of 3m/s and momentum ratio of 2 and 4 for 2 different cases.
INTRODUCTION:
Mixing Tee is a device used in many industries which is used for mxing two fluids at a particular temperature and velocity to get the required output. Used in petrochemical industries and in application such as HVAC etc
SOLVING AND MODELLING APPROACH:
1.Preprocessing (Defining and solving the Geometry)
2.Meshing the Geometry
3.Setup Boundary conditions
4.Solving
5.Post processing (Analyze the Results)
Here we are going to perform simulation for 2 cases,
CASE I:
1a).Geometry configuration - Mixing Tee short
Hot inlet velocity - 3m/s
For Momentum ratio - 2 & K - Epsilon , where (Momentum ratio = velocity at cold inlet / velocity at hot inlet).Hence, cold inlet velocity is 6m/s.
1b).Geometry configuration - Mixing Tee short
Hot inlet velocity - 3m/s
For Momentum ratio - 4 & K - Omega , where (Momentum ratio = velocity at cold inlet / velocity at hot inlet).Hence, cold inlet velocity is 12m/s.
CASE II:
2a).Geometry configuration - Mixing Tee Long
Hot inlet velocity - 3m/s
For Momentum ratio - 2 & K-Epsilon , where (Momentum ratio = velocity at cold inlet / velocity at hot inlet).Hence, cold inlet velocity is 6m/s.
2b).Geometry configuration - Mixing Tee Long
Hot inlet velocity - 3m/s
For Momentum ratio - 4 & K - Omega, where (Momentum ratio = velocity at cold inlet / velocity at hot inlet).Hence, cold inlet velocity is 12m/s.
PRE-PROCESSING
Extracting the fluid volume only in ASYS - SPACE CLAIM
For case 1a & 1b
For case 2a & 2b
MESHING THE GEOMETRY
CASE 1a & 1b: MIXING TEE SHORT
MESH ELEMENT QUALITY STATISTICS
CASE 2a & 2b: MIXING TEE LONG
MESH ELEMENT QUALITY STATISTICS
SETTING UP BOUNDARY CONDITIONS
CASE 1a & 1b: MIXING TEE SHORT
Solved for K-Epsilon with Momemtum Ratio of 2
Solved for K-Omega with Momemtum Ratio of 4
CASE 2a & 2b: MIXING TEE LONG:
Solved for K-Epsilon with Momemtum Ratio of 2
Solved for K-Omega with Momemtum Ratio of 4
SOLVING
CASE 1a: MIXING TEE SHORT
Residual plot:
PLOT - Area Weighted Average of Temperature:
PLOT - Standard Deviation of Temperature at outlet:
CASE 1b: MIXING TEE SHORT
Residual plot:
PLOT - Area Weighted Average of Temperature:
PLOT - Standard Deviation of Temperature at outlet:
CASE 2a: MIXING TEE LONG
Residual plot:
PLOT - Area Weighted Average of Temperature:
PLOT - Standard Deviation of Temperature at outlet:
CASE 2b: MIXING TEE LONG
Residual plot:
PLOT - Area Weighted Average of Temperature:
PLOT - Standard Deviation of Temperature at outlet:
RESULTS
CASE 1:
TEMPERATURE CONTOUR PLOT
MIXING TEE SHORT WITH MOMENTUM RATIO 2
MIXING TEE SHORT WITH MOMENTUM RATIO 4
VELOCITY CONTOUR PLOT
MIXING TEE SHORT WITH MOMENTUM RATIO 2
MIXING TEE SHORT WITH MOMENTUM RATIO 4
TEMPERATURE LINE PLOT
MIXING TEE SHORT WITH MOMENTUM RATIO 2
MIXING TEE SHORT WITH MOMENTUM RATIO 4
VELOCITY LINE PLOT
MIXING TEE SHORT WITH MOMENTUM RATIO 2
MIXING TEE SHORT WITH MOMENTUM RATIO 4
CASE 2:
TEMPERATURE CONTOUR PLOT
MIXING TEE LONG WITH MOMENTUM RATIO 2
MIXING TEE LONG WITH MOMENTUM RATIO 4
VELOCITY CONTOUR PLOT
MIXING TEE LONG WITH MOMENTUM RATIO 2
MIXING TEE LONG WITH MOMENTUM RATIO 4
TEMPERATURE LINE PLOT
MIXING TEE LONG WITH MOMENTUM RATIO 2
MIXING TEE LONG WITH MOMENTUM RATIO 4
VELOCITY LINE PLOT
MIXING TEE LONG WITH MOMENTUM RATIO 2
MIXING TEE LONG WITH MOMENTUM RATIO 4
OUTPUT COMPARISON FOR TWO CASES OF MIXING TEE
HERE ONLY 2 TYPICAL SUBCASES ARE TAKEN FOR EVALUATION
| GEOMETRY CONFIGURATION | NODES | ELEMENTS | AVERAGE OUTLET TEMPERATURE | NO.OF ITERATIONS FOR CONVERRGENCE | STANDARD DEVIATION AT THE OUTLET |
| MIXING TEE SHORT WITH MR 4 | 23028 | 116002 | 27.6℃ | 300 | 1.38℃ |
| MIXING TEE LONG WITH MR 2 | 11771 | 56981 | 30.3℃ | 300 | 1.35℃ |
MESH INDEPENDENT TEST
CONCLUSION:
Here a total of 2 cases with each 2 subcases is taken into consideration and the simulation is carried out.For each of the subcases,both the k epsilon and k-omega SST turbulence model is taken and the calculation is performed.In case 1b of mixing tee with momentum ratio of 4 , it is observed that the outlet temperature varies slightly compared to case 2aof the mixing tee long with momentum ratio of 2,and the diffusion at the mixing of both the incoming fluids (air) in short tee is higher than the long tee which is desired output .
The results are compared with temperature (contour&line) plot and with velocity contour&line) plot.So, it is recommended that the mixing tee with short configurations of momentum ratio 4 can be used for the required applications.
link to download file:
https://drive.google.com/file/d/133x-HmezTi9IiLlzZK72NQE2FN7M_wKW/view?usp=share_link