UNIVERSITI TEKNOLOGI MARA
EFFECT OF BAFFLE DESIGN CONFIGURATION TO THE FLOW
PERFORMANCE OF A SERVCO FUME CUPBOARD
MOHD AMAL ASROL BIN OMAR
Thesis submitted in fulfilment of the requirements for the degree of
Master of Science
Faculty of Mechanical Engineering
February 2018
ABSTRACT
Fume cupboard is a commercial product which has played a significant role in science and technology industry. An efficient fume cupboard should be able to maintain a safe level of airborne contaminants in workplace by controlling and removing them from the worker's environment. Airborne contaminants sometimes leak into the user's breathing zone due to inefficient design of the fume cupboard. This happened when the contaminants entrapped in the recirculation region leak to the vicinity area of the fume cupboard. Leakage of the hazardous chemical out of the fume cupboard's working chamber may pose a threat to the users depending on the types of the chemicals. One of the main components in a fume cupboard is a baffle that helps in distributing airflow in the working chamber up to the exhaust duct. The position, shape and size of the baffle create different flow behaviours inside the fume cupboard thus affect the recirculation region. They also in turn influence the flow in the vicinity of the fume cupboard. The aim of this study is to improve the flow pattern in a fume cupboard by introducing different openings and perforation on the baffle. In this thesis, a Servco fume cupboard equipped with a half Y-shaped baffle with different openings and perforation are simulated and analysed using computational fluid dynamic (CFD) NUMECA software.
Prior to that, grid independence study and parameter validation are carried out with respect to the experimental result. It is observed that the flow uniformity index at the inlet of the fume cupboard is improved when openings with different location and shapes are applied to the baffle. Introduction of opening on the baffle at the location just below the slanted component of the baffle shows improvement of flow quality in comparison to other locations and the original baffle without opening. It is also noticed that the baffle with circle shape perforations produces better uniformity index in comparison to the others. Aside from that, the number of perforations on the baffle also leads to the improvement of uniformity index. For validation purpose, the same fume cupboard with original baffle is simulated and the result is compared with experimental data. Both results are in close agreement with each other for the selected points of comparison with less than 10% error.
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ACKNOWLEDGEMENT
First and foremost, The God Almighty is the one and only whom should all things coming from and return back to Him. Thus, I thank God for every opportunity that I have been entrusted to in successfully completing this long and challenging journey. I would like to express my gratitude to my supervisor Prof. Dr. Wirachman Wisnoe for his support, motivation and perseverance in assisting me along this journey.
My appreciation goes to the managing director and his board of management of Servco Resources Sdn Bhd for their big heart and ambition who provided the facilities and assistance in accomplishing this project.
Aside from that, my gratitude goes to Quah Chong Jin for his help in Numeca.
Furthermore, I would like to show my grateful feeling to my beloved wife and daughters for their understanding and being a constant source of my aspiration in challenging myself by completing this work. Not to forget all my extended families especially my dear mother and late father who responsible for my upbringing and determined character.
TABLE OF CONTENTS
Page
CONFIRMATION BY PANEL OF EXAMINERS ii
AUTHOR'S DECLARATION iii
ABSTRACT iv ACKNOWLEDGEMENT v
LIST OF TABLES viii LIST OF FIGURES ix LIST OF SYMBOLS xii LIST OF ABBREVIATIONS xiii
CHAPTER ONE: INTRODUCTION 1
1.1 Background 1 1.2 Problem Statement 3
1.3 Hypothesis 4 1.4 Research Questions 4
1.5 Objectives 4 1.6 Scope and Limitation of the Study 4
1.7 Significance of the Study 5
1.8 Thesis Outline 6 CHAPTER TWO: LITERATURE REVIEW 8
2.1 Introduction 8 2.2 Research on Fume Cupboard 8
2.3 Perforation 14 2.3.1 Shape of Perforation 15
2.3.2 Size of Perforation 15 2.4 Flow Uniformity Index 16
2.5 Summary 17 CHAPTER THREE: METHODOLOGY 18
3.1 Introduction 18 3.2 Experimental Set-Up 21
3.2.1. Preparation of Fume Cupboard 25
3.3 Grid Independence Study 26 3.4 Parameter Validation 27
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3.5 Fume Cupboard CFD Simulation 30
3.6 Summary 40 CHAPTER FOUR: RESULTS AND ANALYSIS 41
4.1 Introduction 41 4.2 Experimental Results 42
4.3 Grid Independence 43 4.3.1 Point A 44 4.3.2 Point B 45 4.4 Parameter Validation 46
4.5 Flow in Fume Cupboard 48 4.6 Effect of Gap and Its Location 53 4.7 Shape of Baffle Opening 55 4.8 Flow Uniformity Index Against Blockage Ratio 59
4.9 Flow Uniformity Index Against Number of Perforation, N 64
4.10 Summary 67 CHAPTER FIVE: CONCLUSION AND RECOMMENDATION 70
REFERENCES 73 AUTHOR'S PROFILE 78
