i ANALYSIS OF FILM CONDENSATION IN HORIZONTAL MICROCHANNELS WITH VARIOUS CHANNEL SHAPES USING ANSYS MU AMMAL ASHSHIDDIQI This project is submitted in partial fulfillment of the requirement for the award of the Bachelor Degree of Mechanical Engineering with Honours Faculty Of Mechanical and Manufacturing Engineering University Tun Hussein Onn Malaysia JUNE 2017
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iii ACKNOWLEDGEMENT Alhamdulillah all praises to Allah who gives me the strength and His blessing so that I could complete this thesis. My appreciations are firstly dedicated to my parents who always make me getting up whenever I am feeling down. Secondly, thanks to my brothers and sisters, without you come into my mind I would feel dispirited every day. Thirdly, thanks to Dr. Akmal Nizam Bin Mohammed who always guide me patiently. And thanks to Mr Rosman Bin Tukiman for giving me permission to work in Computational Fluid Dynamics Laboratory so that I could perform the research. To all my friends, even though I couldn t state your name one by one in this paper, but your name were always tattooed across my heart as my second family. Thanks for every support you gave to me. Finally, thanks to you who directly or indirectly supporting me for this report or anything, for me even if you don t see me as a real friend but I remember you as my brother. Thank you very much.
iv ABSTRACT The film condensation of refrigerant R-134a in circular (diameter 1 mm), triangular (side 1 mm), inverted triangular (side 1 mm), square ( side 0.5, 1, 2, 3, 5 mm), rectangular (sides 1x1.5 and 1.5x1 mm) are numerically studied through ANSYS Fluent 16.1. The effect of channel shape was investigated where the wall temperature is uniform with velocity inlet of vapor 3 ms -1 and vapor inlet temperature at 90 o C. The results showed that The film thickness is grow gradually in 0-100 mm from inlet and then has not much change along 200 mm outlet. Although the film thickness is generated in every microchannel and even the film generated is almost equally (except square with side 5 mm), the square channel come out with higher heat transfer coefficient than other channel shape.
v ABSTRAK Filem kondensasi bahan pendingin R-134a dalam pekeliling (diameter 1 mm), segi tiga (sebelah 1 mm), segi tiga terbalik (sebelah 1 mm), persegi (sebelah 0.5, 1, 2, 3, 5 mm), segi empat tepat (pihak 1x1 0,5 dan 1.5x1 mm) yang berangka belajar melalui ANSYS Fluent 16.1. Kesan bentuk saluran disiasat di mana suhu dinding adalah seragam dengan kelajuan wap inlet 3 ms -1 dan suhu masuk wap pada 90 o C. Hasil kajian menunjukkan bahawa Ketebalan filem berkembang secara beransur-ansur dalam 0-100 mm dari inlet dan kemudian tidak mempunyai banyak perubahan di sepanjang 200 mm - outlet. Walaupun ketebalan filem yang dihasilkan di dalam setiap saluran mikro dan juga filem yang dihasilkan adalah hampir sama (kecuali persegi dengan sisi 5 mm), saluran persegi keluar dengan pekali pemindahan haba yang lebih tinggi daripada bentuk saluran lain.
vi TABLE OF CONTENTS TITTLE DECLARETION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES LIST OF SYMBOLS LIST OF APPENDICES i ii iii iv v vi viii ix x xi CHAPTER 1 INTRODUCTION 1 1.1 Background 2 1.2 Problem statement 3 1.3 Objectives 3 1.4 Scope of study 3 1.5 Significant of study 4 CHAPTER 2 LITERATURE REVIEW 5 2.1 Microchannel 5 2.2 Heat transfer in microchannel 5 2.2.1 Microchannel condensation 6 2.2.2 Film condensation in horizontal tubes 7 2.3 Computational Fluid Dynamics (CFD) 8 2.3.1 The need of CFD 8
vii 2.4 Related study 9 CHAPTER 3 METHODOLOGY 14 3.1 Research procedure 15 3.2 Working Fluid 16 3.3 Governing equation 16 3.4 Channel shape geometries 18 3.5 Computational Fluid Dynamic simulation and analysis 19 3.5.1 Pre-processing 19 3.5.2 Solver 25 3.5.3 Post processing 26 3.5.4 Basic procedure for a complete simulation by using ANSYS Fluent 26 CHAPTER 4 RESULTS AND DISCUSSION 27 4.1 Introduction 25 4.2 Discussion 27 CHAPTER 5 CONCLUSION AND RECOMMENDATION 35 5.1 Conclusion 35 5.2 Recommendation 36 REFERENCES 37 APPENDICES
viii LIST OF FIGURES 2.1 Microchannel 5 2.2 Condensation flow inside microchannel 5 2.3 Film condensation inside microchannel 7 2.4 Flow over submarine using CFD 8 2.5 Enhancement factor of condensation average heat transfer coefficient versus contact angle 10 2.6 Annular flow pattern 11 2.7 Injection flow pattern 11 2.8 Bubble flow pattern 12 2.9 Visualization results of condensation flow patterns in TFE-coated tube experiments 12 3.1 Research procedure flow chart 15 3.2 Microchannel cross section 18 3.3 Modelling for circular cross section in ANSYS modeler 19 3.4 Meshing the model in the ANSYS Fluent 20 3.5 Meshing project tree 20 3.6 Mesh setting 21 3.7 ANSYS Fluent setup 22 3.8 ANSYS Fluent calculation setup 25 3.9 Calculation graph indicating convergent 26 4.1 Velocity contour of circular channel 200 mm from inlet 28 4.2 Velocity contour of triangular channel 200 mm from inlet 28 4.3 Velocity contour of inverted triangular channel 200 mm from inlet 29 4.4 Velocity contour of square side 0.5 mm channel 200 mm from inlet 29 4.5 Velocity contour of square side 1 mm channel 200 mm from inlet 30 4.6 Velocity contour of square side 2 mm channel 200 mm from inlet 30
ix 4.7 Velocity contour of square side 3 mm channel 200 mm from inlet 31 4.8 Velocity contour of square side 5 mm channel 200 mm from inlet 31 4.9 Velocity contour of rectangular sides 1x1.5 mm channel 200 mm from inlet 32 4.10 Velocity contour of rectangular sides 1.5x1 mm channel 200 mm from inlet 32 4.16 Film thickness growth along microchannels 33 4.17 Heat transfer coefficient along microchannel 34 LIST OF TABLES 2.1 The advantages of CFD 9
x LIST OF SYMBOLS o C mm m K V μ k ω ρ σ Ca Re W S Dh P h δ - Degree Celsius - Millimeter - Meter - Kelvin - Velocity - Dynamic Viscosity - k-omega (Turbulent flow model) - Density - Surface tension - Capillary number - Reynolds number - Watt - Second - Hydraulic diameter - Pressure - Heat transfer coefficient - Film thickness
xi LIST OF APPENDICES A B C Contour velocity Contour Temperature Contour Pressure