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ADDIS ABABA UNIVERSITY ADDIS ABABA INSTITUTE OF TECHNOLOGY SCHOOL of MECHANICAL AND INDUSTRIAL ENGINEERING THERMAL AND ENERGY CONVERSION STREAM A Thesis Submitted to AAIT for the Fulfillment of Master of Science in Mechanical Engineering (Thermal Engineering). Experimental and Numerical Study of Heat Transfer Characteristics in Traditional and Modern Cook-pot. (A Case Study on Ethiopian Cookware) By: Achamyeleh Muche Advisor: Dr. Abdulkadir Aman H. (Ass. Prof.) OCTOBER – 2018 AAU/AAiT SMIE Declaration I, the under signed, declare that this MSc thesis is my original work, has not been presented for the fulfillment of a degree in this or other university, and all sources and materials used for the thesis work is acknowledged. Achamyeleh Muche Date: _______/_______/___________Signature_____________________ This thesis work has been submitted for examination with my approval as a university advisor. Thesis Advisor Dr. Abdulkadir Aman H. (Ass. Prof.) Date: _______/_______/___________Signature_____________________ Date of submission: October 2018 MSc Thesis / cook pot’s heat transfer analysis AAU/AAiT SMIE Thesis Approval Title: Experimental and Numerical Study of Heat Transfer Characteristics in Traditional and Modern Cook-pot. (A Case Study on Ethiopian Cookware) Submitted by Achamyeleh Muche for the partial fulfillment of the requirements for the Degree of Master of Science in Mechanical Engineering (Thermal Engineering), Submitted to School of Mechanical and Industrial Engineering, Addis Ababa Institute of Technology, Addis Ababa University, Addis Ababa, Ethiopia. Advisor: Dr. Abdulkadir Aman Hassen (Ass. Prof.) Date: ____/_____/______Signature_______ Internal Examiner: Date: ___/_____/______Signature_______ External Examiner: Date: ___/_____/______Signature_______ School Dean: Dr. Yilma Tadesse Birhane (Ass. Prof.) Date: ___/_____/______Signature_______ MSc Thesis / cook pot’s heat transfer analysis AAU/AAiT SMIE Acknowledgment I would like to express my gratitude to all those who gave me the strength to complete this thesis. I am deeply indebted to my advisor Dr. Abdulkadir Aman Hassen (Ass. Prof) whose help, stimulating suggestions and encouragement helped me in all the time of research and writing of this thesis. I acknowledge the financial support from the Addis Ababa Institute of Technology, Addis Ababa University. I would also like to thank the School of Mechanical and Industrial Engineering for providing the facilities and equipment for the experimental work. My classmates from the Department of Mechanical Engineering supported me in my research work. I want to thank them for all their help, support, interest and valuable hints. MSc Thesis: Cook-pots Heat Transfer Analysis i AAU/AAiT SMIE Abstract The development in the design of cooktops and cookware with an increasing energy cost needs a research. This study was taken up to research the heat transfer characteristics of different cookpots on electric coil and identify the most appropriate pots. Experimental analysis and numerical simulations on different cookpots apply for determination of cookpot’s thermal behavior. Clay and metal made cookpots have been considered for the analysis. Both experimental and numerical study made separately for a clay pot and metal pot, those contains water as cooking material (water boiling test). In this paper, a methodology for evaluating the thermal efficiency of a pot on an electric stove using experimental methods and numerical simulations in Ansys transient thermal were presented. The numerical simulations and experimental tests corresponded well with one another. The experimental data were collected using commercial Ethiopian cookpots (metallic and clay made ‘shekla’). From the experimental work, the cookpot’s actual heating property and thermal efficiency had been determined. for the case study, the experiments were done using only an electrical stove, and all the tests were carried out at a power input level of 1500 W. The corresponding constant heat flux is applied directly through the bottom surface of the pot. By modeling similar cookpots with the experimental one, transient thermal simulation gives the result, that shows the existing heat transfer properties, like; heat transfer pattern, heat flux distribution, temperature gradient and overall efficiency of the cookpot throughout the pot surface, graphically and numerically. The numerical results then compared with experimental measurements to set the difference. From this result, the convection and radiation losses are less in case of optimum height to diameter ratio so thermal efficiency is highest among the cooking pots hence the large amount of heat energy has to be saved during cooking process. The effects of the parameters like stove to pot contact area, bottom flatness, body shape, filling amount, thickness, handle and ratios of diameter vs depth also addressed. Then after, the study extended to recommend the cookpot that have relatively good heat transfer behavior than the existing one. Keywords: Cookpot; Heat transfer; Thermal efficiency; Energy saving; Ansys transient thermal. MSc Thesis: Cook-pots Heat Transfer Analysis ii AAU/AAiT SMIE Contents Acknowledgment ....................................................................................................................... i Abstract ..................................................................................................................................... ii List of Tables .......................................................................................................................... vii List of Figures ....................................................................................................................... viii Nomenclatures .......................................................................................................................... x CHAPTER ONE ...................................................................................................................... 1 INTRODUCTION ................................................................................................................... 1 1.1. Background of the Study ............................................................................................. 1 1.2. Problem Statement ...................................................................................................... 2 1.3. Objectives .................................................................................................................... 4 1.3.1. General objective ................................................................................................. 4 1.3.2. Specific objectives ............................................................................................... 4 1.4. Methodology ............................................................................................................... 5 1.5. Scope of the Study....................................................................................................... 6 CHAPTER TWO ..................................................................................................................... 7 LITERATURE REVIEW ....................................................................................................... 7 2.1. Heat Transfer Basis ..................................................................................................... 7 2.2. Modes of Heat Transfer ............................................................................................... 7 2.3. What is Cooking? ........................................................................................................ 8 2.4. Cooking Heat Transfer ................................................................................................ 9 2.4.1. Boiling and evaporation ..................................................................................... 10 2.5. Review of Related Literatures ................................................................................... 11 2.6. History of Ethiopian’s Cooking Methodology .......................................................... 13 2.6.1. Stages of firing ................................................................................................... 17 2.6.2. Kinds of Pots ...................................................................................................... 18 2.6.3. Potters ................................................................................................................ 18 2.7. Food Contact Materials ............................................................................................. 18 2.7.1. Properties of metallic food contact materials ..................................................... 19 2.7.2. Properties of clay, food contact materials .......................................................... 22 2.8. Characteristics of Quality Cookware ........................................................................ 23 2.8.1. Good conductivity .............................................................................................. 23 MSc Thesis: Cook-pots Heat Transfer Analysis iii AAU/AAiT SMIE 2.8.2. Uniform heat distribution ................................................................................... 24 2.8.3. Proper thickness/Gauge ..................................................................................... 24 2.9. Methods of Improving Cooking Performance .......................................................... 25 2.9.1. Sandwiching metals ..........................................................................................