Cooling

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Free Convection
Cooling Variation in Terms of Position

By
Joseph Saba
Rula Dahdal
Wassim Naddi

Submitted to
Dr. Michel Daaboul

A research paper submitted in partial fulfillment of the requirements of the course MECH 321 Heat Transfer

Faculty of Engineering
University of Balamand

June 2012
Copyright © 2012, Joseph Saba, Rula Dahdal, Wassim Naddi
All Rights Reserved

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ABSTRACT
This research paper aims is to introduce a brief positioning on how we can enhance the process of cooling refrigerant tanks. This process is usually done globally, both domestically and inside shops in the market s. Yet, there is no specific awareness for both marketing specialist –sellers- or to regular public, on the effect of the position on the cooling rate. In this brief study, we investigated three different cases, assuming there is no effect of conduction or radiation heat transfers on the process of cooling .

This paper starts with a brief definition, in addition to a historical review of heat transfer, and how it progressed to be separate science nowadays. I ntroduction to the different kinds of heat transfer phenomena is also introduced to the readers who have no background of what does heat transfer and its types mea n. In depth, explanation of the process of free or natural convection is carried out ; including the variables, dimensionless factors, and conditions involved. Afterwards, this document gives instructions on how to calculate the total heat transfer for a st andard carbonated drink container. Moreover, just following the detailed instructions, any reader would be able to use this data to determine the heat transfer rate for any cylindrical container, by just replacing values of certain variables. At the end of this document, conclusions are drawn based on theoretical data obtained for the different three cases/positions investigated.

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TABLE OF CONTENTS
ABSTRACT

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TABLE OF CONTENTS

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CHAPTER 1: INTRODUCTION

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1.1 What is heat transfer?

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1.2 Heat Transfer Nowadays

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CHAPTER 2: Convective Heat Transfer

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2.1 Free-Convection Heat Transfer on a Cylinder

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CHAPTER 3: CALCULATIONS

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3.1 Methodology and Formulas

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3.2 Results

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CHAPTER 4: RESULTS AND CONCLUSIONS

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Appendix Table A4

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References

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CHAPTER 1
INTRODUCTION
1.1 What is Heat Transfer?
At the beginning, heat was associated to the feeling of warmth; that was associated with the first feelings of mankind. [1] Explaining what heat transfer me ans requires introducing two types of terms, heat and transport. Heat is a form of energy. Transport is the movement from one place to another. However, the motivation for the movement of this energy is the difference in temperature. As defined by Christop her Long, “Heat is a transport of energy due to a temperature difference”. [2]

Before the eighteenth century, heat was though to be carried out by what so called “caloric” or “heat fluid”. This was a corner stone to allow scientists to develop heat transfer expressions as if flowing in a stream. In the nineteenth century, both work and heat were identified as processes of energy transfer between a system and the surroundings. Furthermore, the first and second laws of thermodynamics govern both of heat and work. The first law is the statement of energy conservation, but it distinguished heat from work in that it cannot be changed from one type of energy to another. As for the second law of thermodynamics, it elaborates the direction through which hea t flows; supported by the fact that it cannot be passed from a cold body into a hot body. [2]

1.2 Heat Transfer Nowadays
After becoming a separate science, heat transfer deals with the rate at which this type of energy is transferred. Before going into any details, it is worth mentioning that

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temperature is directly related to the kinetic energy of the particles at a specific place in an...
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