Assignment CFD

8/8/2019 Assignment CFD

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TABLE OF CONTENT

1.0 INTRODUCTION TO THE PROBLEM 2

2.0 PICTURE OF THE ROOM 2

3.0 DESCRIPTION AND ASSUMPTIONS 3

4.0 DESCRIPTION ON THE BOUNDARY CONDITIONS 3

5.0 RESULTS, ANALYSIS AND DISCUSSIONS 4

5.1 First Conditions 4

5.2 Second Conditions 8

5.3 Third Conditions 11

6.0 CONCLUSION 14

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1.0 INTRODUCTION TO THE PROBLEM

As a group of consultant, we were required to make analysis in Dr. Norshah room by using

our CFD expertise to simulate the air velocity and temperature distribution in his room. Dr

Norshah is saying that the air in his room feels stagnant and quiet hot. The dimension of his

room is 3.5 x 4.5 m. The height of the ceiling is 2.5m. There were couples of furniture such

desk, chair and cupboards. There are three big cupboards lay in front of the wall and one

small cabinet and desk. There is one source of air inflow to the room on the ceiling with 0.5 x

0.5 m of dimension and one for outflow. It can be assume that no air leak through the window

and door.

2.0 THE REAL PICTURE OF THE ROOM

2

CUPBOARD

CUPBOARD

DESK


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3.0 DESCRIPTION ON THE CFD MODEL AND ASSUMPTIONS MADE

1. Model 3D design of Dr. Norshah Room using Gambit with unstructured mesh and size

function below 100,000.

2. Make an analysis using Fluent by taking assumption of three differents air temperature and

velocity from one inlet and one outlet at his room:

i. 1 m/s and 14oC

ii. 2 m/s and 15oC

iii. 3 m/s and 16oC

3. Assumption for initial room temperature = 27oC (300K)

4. Adiabatic walls, windows and doors. (no heat transfer)

5. Neglect the heat from any souce including sun radiations, computer and printer.

4.0 DESCRIPTION ON THE BOUNDARY CONDITIONS

Figure 1: Description of the boundary condition

3

Velocity

Lecturer

PressureCabine


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5.0 RESULT, ANALYSIS AND DISCUSSION

Model the room with the cabinet, inlet and outlet section using Gambit. Mesh using

unstuctured mesh and size function and achieve the total mesh below 100,000. The result

shown in a Figure 2 with total mesh achieved is 81,490.

Figure 2: Result of Unstructured Mesh using Gambit

5.1 First Condition

- Inlet Velocities = 1m/s

- Inlet Temperature = 14oC

Figure 3: Residual Plot with Velocity and Energy Iterations

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Figure 4: Velocity Vector Plot

From the Figure 4, notice that cooled air entering the room is from the inlet with the velocity

of 1m/s (yellow colour indicator). In a moment of circulation process inside the room, the

velocities become around 0.15-0.20 m/s through the whole area inside the room (blue colour

indicator). From the analysis gathered, compute the flux report of Mass Flow Rate in the inlet

and outlet session.

Mass Flow Rate (kg/s)

-------------------------------- ------------------

inlet 0.44100001

outlet -0.44161516

---------------- --------------------Net -0.00061515202

Next, turn on the energy equation to add the temperature equation. Set the air inlet

temperature as 14oC.

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Figure 5: Velocity Vector Plot with Temperature

From the Figure 5, notice that the inlet temperature is 287K (14 oC) from the dark blue colour

indicator. Since the process of circulation in the room, the temperature becomes around 292

K (19oC) major distributions inside the room (light blue colour indicator).

Below are the result gained for Total Heat Transfer Rate inside the room.

Total Heat Transfer Rate (w)

-------------------------------- --------------------

inlet -4948.7677

outlet 3474.8674

---------------- --------------------

Net -1473.9003

In order to monitor the temperature and velocity at the visitor sitter and lecturer sitter, create

two points in the Fluent and run the analysis to get the result. Figure 6 below show the two

points created which is the place need to run the analysis.

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Figure 6: Two Points Created

Below are the result obtained:

Average of Surface Vertex Values

Static Temperature (k)

-------------------------------- --------------------

point-lecturer 290.19949

point-visitor 290.10187

---------------- --------------------

Net 290.1507


Velocity Magnitude (m/s)

-------------------------------- --------------------



---------------- --------------------

Net 0.091790527

7

Visitor

Lecturer


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5.2 Second Condition





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and outlet session.


-------------------------------- --------------------

inlet 0.88200002

outlet -0.88299642

---------------- --------------------

Net -0.00099640621




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From the Figure 9, notice that the inlet temperature is 288K (15 oC) from the dark blue colour

indicator. Since the process of circulation in the room, the temperature becomes around 293

K (20oC) major distributions inside the room (light blue colour indicator).



-------------------------------- --------------------

inlet -9009.8635

outlet 7505.4174

---------------- --------------------

Net -1504.4461

In order to monitor the temperature and velocity at the visitor sitter and lecturer sitter, two

points has been created before. Figure 6 above show the two points created which is the place

need to run the analysis. Below are the results obtained.



-------------------------------- --------------------



---------------- --------------------

Net 289.70862


Velocity Magnitude (m/s)-------------------------------- --------------------



---------------- --------------------

Net 0.16524994

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5.3 Third Condition





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and outlet session.


-------------------------------- --------------------

inlet 1.323

outlet -1.3243461

---------------- --------------------

Net -0.0013460967




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From the Figure 12, notice that the inlet temperature is 289K (16oC) from the dark blue

colour indicator. Since the process of circulation in the room, the temperature becomes

around 294 K (21oC) major distributions inside the room (light blue colour indicator).



-------------------------------- --------------------

inlet -12183.288

outlet 10707.086

---------------- --------------------

Net -1476.2026

In order to monitor the temperature and velocity at the visitor sitter and lecturer sitter, two

points has been created before. Figure 6 above show the two points created which is the place

need to run the analysis. Below are the results obtained.



-------------------------------- --------------------



---------------- --------------------

Net 290.1131


Velocity Magnitude (m/s)-------------------------------- --------------------



---------------- --------------------

Net 0.25480753

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6.0 CONCLUSION

Where:i. 1 m/s and 14oC

ii. 2 m/s and 15oC

iii. 3 m/s and 16oC

Name of Group Members Mark Weightage SignatureMOHD HAFIZ BIN MUHAIYADIN ( ME 079689 ) 1

MOHD AZIZUL BIN ABD AZIZ ( ME 080181 ) 1MUHAMAD WAQAR HAMMAN B ALIAS ( ME 080092 ) 1

MOHAMAD HIDAYAT BIN ZAINUL MASRI (ME 080124) 1

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Mass Flow Rate

(kg/s)

Total Heat Transfer

(kW)

Static Temperature

(oC)

Velocity Magnitude

(m/s)

i ii iii i ii iii i ii iii i ii iii

Inlet 0.441 0.882 1.323 4.95 9.01 12.18 - - - - - -

Outlet 0.442 0.883 1.324 3.47 7.51 10.71 - - - - - -

Lecturer-Pt - - - - - - 17.20 16.82 17.18 0.072 0.092 0.155

Visitor-Pt - - - - - - 17.10 16.59 17.05 0.111 0.238 0.354

Assignment CFD

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