Air Flow And Temperature Distribution Analysis In An Air Conditioned Car.

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AIR FLOW AND TEMPERATURE DISTRIBUTION ANALYSIS IN AN AIR

CONDITIONED CAR

KHOR MEI YIN

B041110056

BMCT

Email: [email protected]

Draft Final Report

Projek Sarjana Muda II

Supervisor: DR. TEE BOON TUAN

Faculty of Mechanical Engineering

Universiti Teknikal Malaysia Melaka

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SUPERVISOR DECLARATION

“I hereby declare that I have read this thesis and in my opinion this report is sufficient in terms of scope and quality for the award of the degree of

Bachelor of Mechanical Engineering (Thermal-Fluids)”

Signature : ……… Supervisor : ………

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AIR FLOW AND TEMPERATURE DISTRIBUTION ANALYSIS IN

AN AIR CONDITIONED CAR

KHOR MEI YIN

This Technical Report is submitted to

Fakulti Kejuruteraan Mekanikal, Universiti Teknikal Malaysia Melaka

In partial fulfilment for

Bachelor of Mechanical Engineering (Thermal-Fluids) with honours

Fakulti Kejuruteraan Mekanikal

Universiti Teknikal Malaysia Melaka

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DECLARATION

“I hereby declare that the work in this report is my own except for summaries and quotations which have been duly acknowledged.”

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ACKNOWLEDGEMENT

First of all, I would like to express my gratitude to my supervisor, Dr. Tee Boon Tuan, who has helped me so much by constantly imparting his knowledge and ideas so that I could complete this project successfully. Sincere thanks to Dr. Yusmady Mohamed Arifin for evaluating my final year project. The ideas and suggestions given were valuable for me to complete this project.

Besides that, I would also like to thank Faculty of Mechanical Engineering (FKM), Universiti Teknikal Malaysia Melaka (UTeM) for giving me this opportunity to complete this project and allowing me to utilize all the necessary equipment and tools needed for this study.

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ABSTRACT

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ABSTRAK

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

SUPERVISOR DECLARATION ii

DECLARATION iv

ACKNOWLEDGEMENT vi

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENTS ix

LIST OF TABLES xiii

LIST OF FIGURES xv

LIST OF SYMBOLS xviii

LIST OF APPENDICES xix

LIST OF ABBREVIATIONS xx

CHAPTER 1 INTRODUCTION

1.1 OVERVIEW 1

1.2 PROBLEM STATEMENT 1

1.3 OBJECTIVES 2

1.4 SCOPES 2

1.5 EXPECTED OUTCOMES 2

CHAPTER 2 THEORY

2.1 OVERVIEW 3

2.2 ENVIRONMENTAL PARAMETERS OF

VEHICLE 3

2.3 THERMAL COMFORT 4

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CHAPTER TITLE PAGE

2.3.2 Personal Factors 5 2.3.3 Predicted Mean Vote (PMV) 6 2.3.4 Predicted Percentage Dissatisfied (PPD) 6 2.4 HEATING, VENTILATION AND AIR

CONDITIONING (HVAC) SYSTEM IN

VEHICLES 7

2.4.1 Air Flow Operation 7 2.4.2 Air Conditioning Operation 8 2.5 COMPUTATIONAL FUID DYNAMICS (CFD) 9

2.5.1 Geometry Modelling 10 2.5.2 Mesh Generation 10

2.5.3 Solver Method 11

2.5.4 Display Of Results 12 2.6 TURBULENCE MODELLING 13

CHAPTER 3 LITERATURE REVIEW

3.1 OVERVIEW 15

3.2 CFD ANALYSIS OF AIR FLOW AND

TEMPERATURE DISTRIBUTION IN AN AIR CONDITIONED CAR BY

RAMESHKUMAR et al. (2013) 15

3.2.1 Methodology 16

3.2.2 Results And Discussion 17

3.2.3 Conclusion 19

3.3 NUMERICAL ANALYSIS OF AIR FLOW AND TEMPERATURE FIELD IN A PASSENGER CAR COMPARTMENT BY

HASLINDA et al. (2011) 20

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CHAPTER TITLE PAGE

3.4 STUDIES OF THE THERMAL COMFORT

INSIDE OF THE PASSENGER COMPARTMENT USING THE NUMERICAL SIMULATION BY

IVANESCU et al. (2010) 23

3.4.3 Conclusion 27

3.5 NUMERICAL SIMULATION OF AIR CONDITIONING VEHICLE USING

COMPUTATIONAL FLUID DYNAMICS BY

WANG AND XIANG (2009) 28

3.5.3 Conclusion 31

3.6 COMPUTATIONAL ANALYSIS OF THERMAL DISTRIBUTION WITHIN PASSENGER CAR

CABIN BY ZEYA AND JOMON (2013) 32

3.6.3 Conclusion 34

3.7 COMPARISON OF PREVIOUS STUDIES 34

CHAPTER 4 METHODOLOGY

4.1 OVERVIEW 35

4.2 EXPERIMENTAL METHOD 35

4.2.1 Experimental Procedures 38

4.3 NUMERICAL METHOD 39

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CHAPTER TITLE PAGE

4.4 THERMAL COMFORT ANALYSIS METHOD 45 4.4.1 Thermal Comfort Analysis Procedures 46

CHAPTER 5 RESULTS AND DISCUSSION

5.1 OVERVIEW 47

5.2 EXPERIMENTAL RESULTS 47 5.3 SIMULATION RESULTS 51 5.4 COMPARISON OF EXPERIMENTAL

RESULTS AND SIMULATION RESULTS 50 5.4.1 Comparison of Temperature Distribution

Inside Passenger Compartment With

Various Human Loads 50 5.4.2 Percentage Of Error 52 5.5 GRAPHIC SIMULATIONS 53 5.5.1 Simulations of Temperature Distribution 54 5.5.2 Simulations of Air Velocity Distribution 56 5.6 THERMAL COMFORT ANALYSIS 58

CHAPTER 6 CONCLUSION AND RECOMMENDATIONS

6.1 CONCLUSION 61

6.2 RECOMMENDATIONS 62

REFERENCES 63

APPENDIX A: Flow Chart 67

APPENDIX B: Gantt Chart 68

APPENDIX C: Actual Flow of Temperature 69

APPENDIX D: Actual Flow of Air Velocity 69

APPENDIX E: Simulation Flow of Temperature 70

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CHAPTER TITLE PAGE

APPENDIX G: Percentage of Error for Temperature

Distribution 71

APPENDIX H: Percentage of Error for Air Velocity

Distribution 71

APPENDIX I: Thermal Comfort Analysis Evaluation

Report at Driver Seat 72

APPENDIX J: Thermal Comfort Analysis Evaluation

Report atPassenger Seat at Front Region 73

APPENDIX K: Thermal Comfort Analysis Evaluation

Report atRight Side of Rear Passenger

Seat 74

APPENDIX L: Thermal Comfort Analysis Evaluation

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LIST OF TABLES

NO. TITLE PAGE

2.1 Predicted Mean Vote Scale (ISO 7730) 5 2.2 Difference between Experimental Methods and CFD simulation

(Dmitri, 2007) 9

3.1 Computed Values of Air Velocity for Various Human Loads

(Rameshkumar et.al, 2013) 17

3.2 Computed Values of Temperature for Various Human Loads

3.3 General Boundary Conditions (Ivanescu et.al, 2010) 25 3.4 External Boundary Conditions (Ivanescu et.al, 2010) 25 3.5 Air Conditioning Unit Characteristics (Ivanescu et.al, 2010) 25 3.6 Experimental Results and Simulation Results for Air Velocity

(Ivanescu et.al, 2010) 25

3.7 Experimental Results and Simulation Results for Temperature

(Ivanescu et.al, 2010) 26

3.8 Thermal Comfort Indices with Knob of Air Flow Range Inlet on Position 2 (Ivanescu et.al, 2010) 27 3.9 Comparison of Previous Studies 34 4.1 Location of Measuring Point 38

4.2 Turbulence Model Setup 42

4.3 Material Properties 43

4.4 Boundary Conditions Setup 43

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LIST OF FIGURES

2.1 Air Flow Sensation Curve (Musat and Helerea, 2009) 3 2.2 Graph of PPD against PMV (ISO 7730) 6 2.3 Mechanical electronic switches (Zhou, 2013) 7 2.4 Automatic Control of Automobile Air Conditioning

(Janotkova and Pavelek, n.d.) 8 2.5 Overview of ANSYS Workbench (Delfel, 2013) 10

2.6 Mesh Generation Process 11

3.1 Location of Measuring Points inside the Cabin

3.2 Air Velocity Distribution for Human Load of 4

3.3 Temperature Distribution for Human Load of 4

3.4 Comparison of Velocity Distribution for Various Human Loads

3.5 Comparison of Temperature Distribution for Various Human

Loads (Rameshkumar et.al, 2013) 19 3.6 Temperature Distribution for No Glazing Windscreen

(Mohamed Kamar et al., 2011) 21

3.7 Temperature Distribution for CIL Glazing Windscreen

3.8 Temperature Distribution for GIL Glazing Windscreen

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NO. TITLE PAGE

3.11 The Measuring Points for Temperature (Ivanescu et.al, 2010) 24 3.12 Temperature and Velocity Distribution for Knob of Air Flow Range

Setting in Position 2 (Ivanescu et.al, 2010) 26 3.13 Graph of Thermal Comfort Indices against Time with Knob on

Air Flow Inlet in Position 2 (Ivanescu et.al, 2010) 27 3.14 Velocity Distribution at Section x=6.86 m

(Wang and Xiang, 2009) 29

3.15 Velocity Distribution at Section x=9.14 m

3.16 Temperature Distribution at Section x=6.86 m

3.17 Temperature Distribution at Section x=9.14 m

3.18 Comparison of Experimental and Simulation Temperature on

section x=6.86 m (Wang and Xiang, 2009) 31 3.19 Temperature Distribution (Ahmad Quadri and Jose, 2013) 33 3.20 Temperature Distribution with Air Inlets and Outlets

(Ahmad Quadri and Jose, 2013) 33

4.1 Toyota Corolla E110 36

4.2 Interior Arrangement 36

4.3 Dashboard 36

4.4 HVAC System Switches 37

4.5 Anemometer 37

4.6 Location of Measuring Points 37 4.7 Physical Measurement at Head Level of Passenger Seat 39

4.8 CFD Simulation Outline 40

4.9 Dimensions of Toyota Corolla E110 41

4.10 3D Car Cabin Model 41

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NO. TITLE PAGE

5.2 Graph of Average Air Velocity against various Human Loads 51 5.3 Graph of Percentage of Error for Temperature Distribution 52 5.4 Graph of Percentage of Error for Air Velocity Distribution 53 5.5 Temperature Contour with no Human Load inside Passenger

Compartment 54

5.6 Temperature Contour with 1 Human Load inside Passenger

Compartment 55

5.7 Temperature Contour with 2 Human Loads inside Passenger

Compartment 55

Compartment 56

5.10 Velocity Vector with No Human Load inside Passenger

Compartment 56

5.11 Velocity Vector with 1 Human Load inside Passenger

Compartment 57

5.12 Velocity Vector with 2 Human Loads inside Passenger

Compartment 57

Compartment 58

5.15 Graph of PPD against PMV for Driver Seat 59 5.16 Graph of PPD against PMV for Passenger Seat at Front Region 59 5.17 Graph of PPD against PMV for Passenger Seat at Right Side of

Rear Region 59

5.18 Graph of PPD against PMV for Passenger Seat at Left Side of

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LIST OF SYMBOLS

° = degree

°C = degree Celcius % = percentage atm = atmosphere

clo = clothing insulation

σε = turbulent Prandtl numbers for ε σ turbulent Prandtl numbers for k � = turbulent dissipation

G = turbulence kinetic energy due to buoyancy

G = turbulence kinetic energy due to the mean velocity gradients k = turbulent kinetic energy

K = Kelvin kg = kilogram m = meter Pa = Pascal s = second

T = temperature, °C V = air velocity, m/s W = watt

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LIST OF APPENDICES

A Flow Chart 67

B Gantt Chart 68

C Actual Flow of Temperature 69

D Actual Flow of Air Velocity 69 E Simulation Flow of Temperature 70 F Simulation Flow of Air Velocity 70 G Percentage of Error for Temperature Distribution 71 H Percentage of Error for Air Velocity Distribution 71 I Thermal Comfort Analysis Evaluation Report at Driver

Seat 72

J Thermal Comfort Analysis Evaluation Report atPassenger

Seat at Front Region 73

K Thermal Comfort Analysis Evaluation Report atRight Side

of Rear Passenger Seat 74

L Thermal Comfort Analysis Evaluation Report atLeft Side

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LIST OF ABBREVIATIONS

3D = three dimensional

ASHRAE = American Society of Heating, Refrigeration and Air- Conditioning Engineers

ASM = algebraic stress model CAD = Computer Aided Design

CFD = Computational Fluid Dynamics CIL = clear insulated laminate tint DTS = Dynamic Thermal Sensation eqn = equation

GIL = green insulated laminate tint

HVAC = Heating, Ventilation and Air Conditioning IAQ = Indoor Air Quality

PMV = Predicted Mean Vote

PPD = Predicted Percentage of Dissatisfied RANS = Reynolds Averaged Navier-Stokes RNG = Re-Normalisation Group

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CHAPTER 1

INTRODUCTION

1.1 OVERVIEW

Thermal comfort of vehicle passengers has been emphasized due to the increasing in time of people spends inside the vehicles. The passenger compartment is the place which shows significant effect on thermal comfort. It is exposed to internal disturbances such as the speed of vehicle, the number of passengers inside the car cabin and the temperature of engine, and also external disturbances such as air temperature, velocity of wind and solar radiation. (Mezrhab & Bouzidi, 2006) A great temperature control inside the vehicles will provide driver a good physical state of driving and a great visibility by avoiding fogging inside the vehicles. (Alahmer et al., 2010) In order to improve the thermal comfort inside a vehicle, an acceptable range of distribution of air velocity and temperature are to be considered. This project will focus on analyzing the distribution of temperature and velocity inside the vehicle compartment.

1.2 PROBLEM STATEMENT

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simulation can predict the airflow numerically without creating a prototype, thus save cost, time and manpower. Hence, an optimum environment should be able to simulate by using CFD software in analyzing the temperature and air flow inside passenger compartment, in order to improve the thermal comfort level. Thermal comfort of passengers inside vehicle can be evaluated by Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD).

1.3 OBJECTIVES

i. To investigate the temperature and air flow distribution with and without human loads inside the passenger compartment.

ii. To perform thermal comfort analysis inside vehicle.

1.4 SCOPES

i. Evaluate the air flow and temperature distribution by experimental method (measurement) and CFD simulation.

ii. Only indoor environmental condition of the car is taken into consideration. iii. Boundary parameters are determined for valid CFD modelling to be applied

in the car.

1.5 EXPECTED OUTCOMES

i. Physical measurement of distribution of temperature and air velocity in an air conditioned vehicle.

ii. CFD simulation of distribution of temperature and air velocity in an air conditioned vehicle.

iii. Compare results between physical measurement and numerical simulation. iv. Thermal comfort analysis inside the air conditioned vehicle.

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CHAPTER 2

THEORY

2.1 OVERVIEW

All the principles and definitions related to the case study should be included in this chapter. The theories such as thermal comfort, Heating, Ventilation and Air Conditioning (HVAC) system in vehicles, CFD and turbulence modelling are studied and compiled in this chapter for better understanding.

2.2 ENVIRONMENTAL PARAMETERS OF VEHICLE

A vehicle is exposed to both internal disturbances such as car speed, engine temperature and passengers inside car cabin, and also external disturbances such as temperature, sun and wind. This project will focus on environmental parameters that are temperature and air velocity distribution inside the air conditioning car. Figure 2.1 shows the relationship between air velocity and temperature. The air velocity will increase with temperature.

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When the air conditioning system is switched on, the temperature will drop slightly as the cooled air is suddenly directed into the passenger compartment and will rise steadily as time passed. Due to the small space inside passenger compartment, the temperature will be affected by the heat exchange in the space (Zhou, 2013). When there are occupants inside the vehicle cabin, the temperature will increase due to the sensible heat transferred from human body. (Mohamed Kamar et. al., 2013)

The air flow inside the vehicle is directed to a small section due to the limited space of car. The air flows from air conditioning vents will increase the air velocity. It will be blocked by the front seats and rear seats and formed recirculating flow patterns. This flow pattern is well mixed with the cold air from air conditioning inlets and the surrounding heated air inside vehicle cabin, and then directed back to the air conditioning outlets (Jalal and Haider, 2007). Hence, the air velocity will decrease as human loads will occupy certain spaces inside the passenger compartment.

2.3 THERMAL COMFORT

American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) Standard 55 defines thermal comfort as “that condition of mind which expresses satisfaction with the thermal environment”. However, different people have different sensations towards the thermal environment. Hence, six factors are used as an indicator of thermal comfort:

i. Air temperature ii. Air velocity

iii. Radiant temperature iv. Humidity level