# Investigation on the Buoyancy Driven Ventilation in a Chamber with Two Vertical Openings on Two Opposite Sides.

Topics: Hong Kong, Thermodynamics, Temperature Pages: 29 (6774 words) Published: March 24, 2013
Hong Kong Institute of Vocational Education (Tsing Yi) Department of Engineering

Higher Diploma in Mechanical Engineering

Appendix
Major Project (ENG3699) Investigation on the buoyancy driven ventilation in a chamber with two vertical openings on two opposite sides.

Course: Name:
Supervisor:

91301F/L4A WONG Lai King (080054198) Ms Annie Choi (PBA) Mr Jordan Kwong (HKIVE) April 11, 2011

Date:

Hong Kong Institute of Vocational Education (Tsing Yi) Department of Engineering Major Project (ENG 3699) - Mid-Term Report - Appendix

91301F/L4A WONG Lai King (080054198)

Appendix 1 - Critical ratio of inlet to exit opening 1. Type 1 1.1 Case 1 (smaller or equal to 1)
In this case, various exit opening were tested from with the two inlet openings are fixed as ( )/area of inlet ( ) is smaller or equal to 1. No. 1 2 3 4 5 6 7 Area of Air Inlet, Ai (0.21x0.21 m) x2 (0.21x0.21 m) x2 (0.42x0.42 m) x2 (0.42x0.42 m) x2 (0.42x0.42 m) x2 (0.42x0.42 m) x2 (0.42x0.42 m) x2 Area of Air Outlet, Ao 0.1x0.1 m 0.2x0.2 m 0.1x0.1 m 0.2x0.2 m 0.3x0.3 m 0.4x0.4 m 0.5x0.5 m Ao / Ai 0.11338 0.45351 0.02834 0.11338 0.25510 0.45351 0.70862 and to .

After calculation, 7 conditions were met the requirement which is area of exit The following table is the detail of the conditions of case 1:

Exit Openings Inlet Openings Z

Heat Source Y X

Fig. 1 - The sample testing chamber of case 1 (Type 1)

April

4, 2011

Major Project

Page 2 / 33

Hong Kong Institute of Vocational Education (Tsing Yi) Department of Engineering Major Project (ENG 3699) - Mid-Term Report - Appendix

91301F/L4A WONG Lai King (080054198)

1.2 Case 2 (larger or equal to 1)
In this case, the exit opening was fixed as two inlet openings ranging from ( )/area of inlet ( ) is larger or equal to 1. No. 1 2 3 4 5 6 7 8 9 Area of Air Inlet, Ai (0.07x0.07 m) x2 (0.14x0.14 m) x2 (0.21x0.21 m) x2 (0.07x0.07 m) x2 (0.14x0.14 m) x2 (0.21x0.21 m) x2 (0.28x0.28 m) x2 (0.35x0.35 m) x2 (0.42x0.42 m) x2 Area of Air Outlet, Ao 0.3x0.3 m 0.3x0.3 m 0.3x0.3 m 0.6x0.6 m 0.6x0.6 m 0.6x0.6 m 0.6x0.6 m 0.6x0.6 m 0.6x0.6 m Ao / Ai 9.1837 2.2959 1.0204 36.735 9.1837 4.0816 2.2959 1.4694 1.0204 to and . with the

After calculation, 9 conditions were met the requirement which is area of exit The following table is the detail of the conditions of case 2:

Exit Openings

Z

Inlet Openings

Heat Source Y X Fig. 2 - The sample testing chamber of case 2 (Type 1)

April

4, 2011

Major Project

Page 3 / 33

Hong Kong Institute of Vocational Education (Tsing Yi) Department of Engineering Major Project (ENG 3699) - Mid-Term Report - Appendix

91301F/L4A WONG Lai King (080054198)

1.3 Case 3 (similar or equal to 1)
In this case, the exit opening was tried from the two inlet openings ranging from ( )/area of inlet ( ) is similar or equal to 1. No. 1 2 3 4 5 6 Area of Air Inlet, Ai (0.07x0.07 m) x2 (0.14x0.14 m) x2 (0.21x0.21 m) x2 (0.28x0.28 m) x2 (0.35x0.35 m) x2 (0.42x0.42 m) x2 Area of Air Outlet, Ao 0.1x0.1 m 0.2x0.2 m 0.3x0.3 m 0.4x0.4 m 0.5x0.5 m 0.6x0.6 m Ao / Ai 1.02041 1.02041 1.02041 1.02041 1.02041 1.02041 to to . with

After calculation, 6 conditions were met the requirement which is area of exit The following table is the detail of the conditions of case 3:

Exit Openings

Z

Inlet Openings

Heat Source Y X

Fig. 3 - The sample testing chamber of case 3 (Type 1)

April

4, 2011

Major Project

Page 4 / 33

Hong Kong Institute of Vocational Education (Tsing Yi) Department of Engineering Major Project (ENG 3699) - Mid-Term Report - Appendix

91301F/L4A WONG Lai King (080054198)

2. Type 2
In this type, the two exit openings were tried from with the two inlet openings ranging from . After calculation, 6 conditions were met the requirement which is area of exit ( )/area of inlet ( ) is equal to 1. No. 1 2 3 4 5 6 Area of Air Inlet, Ai (0.057x0.057 m) x2 (0.07x0.07 m) x2 (0.14x0.14 m) x2 (0.21x0.21 m) x2 (0.28x0.28 m)...

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