...Project 2 Physics 171 – Professor Reeves Conduction, Convection, and Radiation: Methods of heat transfer Steve Strittmatter Conduction, Convection, and Radiation: Methods of heat transfer. Abstract There are three different types of heat transfer we often discuss in physics. This paper uses example of each type of heat transfer; conduction, convection, and radiation. When breaking down conduction we understand it is the physical transfer of heat. Two objects are touching and the heat from one object transfers to the other object to warm it. In convection we understand it is the flow of matter that moves the heat. Matter is warmed, moves away from the heat source and then other matter that has not been warmed moves closer to the heat source to be warmed. This creates a current allowing the flow of hot matter away and cool matter toward the heat source. Radiation is the other type of heat transfer we discuss; this type of heat transfer takes no matter at all and uses electromagnetic waves to transfer energy (heat) from one object to another. Conduction, convection and radiation are all methods in which heat is transferred from one object to another or from a heat source to an object. In each of these methods heat moves from the higher temperature to the lower temperature until a thermal equilibrium is established. It is the differences of each type of heat transfer that will be discussed in this paper. Before...
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...Heat Heat is always transferred when a temperature difference exists between two bodies. There are three basic modes of heat transfer: Conduction involves the transfer of heat by the interactions of atoms or molecules of a material through which the heat is being transferred. Convection involves the transfer of heat by the mixing and motion of macroscopic portions of a fluid. Radiation or radiant heat transfer, involves the transfer of heat by electromagnetic radiation that arises due to the temperature of a body. CONDUCTION Conductive Heat transfer takes place as conduction if there is a temperature gradient in a solid or fluid Conduction will take place if there exist a temperature gradient in a solid (or stationary fluid) medium. Energy is transferred from more energetic to less energetic molecules when neighboring molecules collide. Conductive heat flow occurs in direction of the decreasing temperature since higher temperatures are associated with higher molecular energy. Fourier's Law expressed conductive heat transfer as: q = k A dT / s Where q = heat transfer (W, J/s, Btu/s)A = heat transfer area (m2 , ft2)k =thermal conductivity of the material(W/m.K or W/m℃, Btu/(hroF ft2/ft))dT = temperature difference across the material (K oroC,oF)s = materialism thickness (m, ft) Example of Heat Transfer by Conduction is A plane wall constructed of solid iron with thermal conductivity 70 W/m℃, thickness 50 mm and with surface area1 m by 1 m,temperature150...
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...Transfer: Conduction, Convection, & Radiation 1 Heat Transfer Basics Tami L. Donnell Humanities 300, History and Methods of Science Professor Datte February 7, 2007 Heat Transfer: Conduction, Convection, & Radiation 2 Heat Transfer Basics What is Heat Transfer? Heat Transfer is the movement of energy due to a temperature difference. In my paper I will discuss Heat Transfer Basics and will address three physical mechanisms of the movement of heat. The three modes are conduction, convection, and radiation. I will offer examples of the three in hopes that you will gain a better understanding of what each one means. By the end of my essay paper you will have gain the knowledge, skills and abilities to define and understand how heat transfer occurs in our daily living. I will begin by given some small information about heat. Heat as some of you may know flows from an area of higher temperature to a region of lower temperature. Heat can also be made to flow from a cooler area to a hotter area in order to do this function; heat is controlled via a system such as a heat pump. Heat is basically made up of molecules as most anything. Molecules are constantly moving so the hotter something maybe the faster the molecules are moving. Eventually, they move at the same speed which means that any object that is hot will become cold. As mentioned previously heat moves from one object to another in three ways: conduction, convection, and...
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...Heat Transfer Conduction When we place one end of an iron rod in a fire, the other end also heats up after a while. We say heat has been conducted along the rod from the hot end. Conduction is the process by which heat is transmitted through a medium from one particle to another. The heat is transmitted from the hot to the cold end. Most metals are good thermal conductors. A metal surface feels colder than a cement surface although they are both at the same temperature. This is because e metal conducts heat away form the hand more quickly than cement which is a poor conductor. Generally, substances which are liquids at ordinary temperatures are poor conductors. One exception is mercury which is a good conductor. Mercury is a metal in the liquid state at room temperature and pressure. The thermal conductivity of gases is even lower than that of liquids. How conduction works Conduction takes place when heat energy is transferred from one particle to the next. When one end of a rod is heated, the particles at this end of the rod gain energy and vibrate more vigorously. These particles collide with their less energetic neighbours. Some of their energy is transferred to these neighbouring particles which in turn gain kinetic energy. In this way, heat energy is passed along the rod by the vibrating particles. Conduction of heat in metals is far better than in other solids. The ‘free’ electrons in a metal are responsible for its superior thermal conductivity....
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...the molecules in an object. Now the three types of heat transfer and first up is Conduction which is the transfer of energy in the form of heat by direct contact through excitement of molecules with driven by a temperature difference. Energy travels from a high to a low and the same thing happens with heat. When the high temperature molecules collide with the low temperature molecules, a transfer of energy occurs from the hot, more energetic molecules to the colder, less energetic molecules and this is recognized as conduction. Conduction is most prevalent in solids but it can also be found in liquids and gases. The rate at which heat is transmitted through a material by conduction depends on thermal conductivity which is a characteristic of a material and its mass. The easiest way to think of conduction is to hold a metal rod by one end and put the other over a fire. Eventually the hot energetic molecules from the fire will transfer to the cold, less energetic molecules of the metal rod and slowly creep up the rod to the cold end where it is being held and then move to the hand and cause burns. The second method of heat transfer is convection which is the transfer of energy through a circulating gas or liquid to or from a solid object. An example of convection is a pot on the hot stove to the water inside which then heats up the pot and the that heats up the water. Convection consists of two energy transfer mechanisms. The first occurs...
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...transfer of energy can occur in a variety of ways, among them conduction, radiation, and convection. Heat is not a property of a system or body, but instead is always associated with a process of some kind, and is synonymous with heat flow and heat transfer. 2. Differentiate heat from temperature The heat is the energy transferred from one body while the temperature is the amount of hotness or coldness of a body. 3. How heat is related to thermal energy Heat is thermal energy in the process of transfer or conversion across a boundary of one region of matter to another, as a result of a temperature difference. In engineering, the terms "heat" and "heat transfer" are thus used nearly interchangeably (heat transfer is the rate of heat flow in time, or the heat power), since heat is always understood to be in the process of transfer. The energy transferred by heat is called by other terms (such as thermal energy or latent energy) when this energy is no longer in net transfer, and has become static. Thus, heat is not a static property of matter. Matter does not contain heat, but rather thermal energy, and even the thermal energy is subject to transformations into and out of other types of energy, and so can be considered to be "conserved" only when these processes are small. 4. Explain how temperature is measured 6. Explain how heat is transferred by conduction, convection and radiation. Conduction- Heat conduction occurs as hot, rapidly moving or vibrating atoms and molecules...
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...69i57j69i59j69i60&sourceid=chrome&es_sm=93&ie=UTF-8#q=explain+the+design+of+a+laboratory+thermometer https://en.m.wikipedia.org/wiki/Silicate_glass#Silicate_glass http://www.livescience.com/39994-kelvin.html 1. Thermal energy transfer by: * Conduction is the flow of heat energy through materials and substances in direct contact with each other. A conductor is a material that permits heat energy to flow freely within it. The better the conductor the more rapidly heat will be transferred. Conduction takes place when heat is supplied to a substance, the particles in that substance gain more energy and vibrate more. These particles then bump into neighboring particles and some of their energy is transferred to them. This process continues and energy is eventually transferred from the hotter end to the colder end of the object. * Thermal convection is transferred from hot places to cold places by convection. Convection occurs when warmer areas of gas or liquid rises to cooler areas of that gas or liquid. The cooler gas or liquid replaces the warmer areas that have risen higher. This results in a continuous circulation pattern. For example Air above the respective land and water surfaces is warmed or cooled by conduction with those surfaces. During the day, the warmer land temperature results in a warmer and therefore, less dense and lighter air mass above the coast as compared with the adjacent air mass over the surface of water. As the warmer air...
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...This page intentionally left blank SEVENTH EDITION Fundamentals of Heat and Mass Transfer THEODORE L. BERGMAN Department of Mechanical Engineering University of Connecticut ADRIENNE S. LAVINE Mechanical and Aerospace Engineering Department University of California, Los Angeles FRANK P. INCROPERA College of Engineering University of Notre Dame DAVID P. DEWITT School of Mechanical Engineering Purdue University JOHN WILEY & SONS VICE PRESIDENT & PUBLISHER EXECUTIVE EDITOR EDITORIAL ASSISTANT MARKETING MANAGER PRODUCTION MANAGER PRODUCTION EDITOR DESIGNER EXECUTIVE MEDIA EDITOR PRODUCTION MANAGEMENT SERVICES Don Fowley Linda Ratts Renata Marchione Christopher Ruel Dorothy Sinclair Sandra Dumas Wendy Lai Thomas Kulesa MPS Ltd. This book was typeset in 10.5/12 Times Roman by MPS Limited, a Macmillan Company and printed and bound by R. R. Donnelley (Jefferson City). The cover was printed by R. R. Donnelley (Jefferson City). Founded in 1807, John Wiley & Sons, Inc. has been a valued source of knowledge and understanding for more than 200 years, helping people around the world meet their needs and fulfill their aspirations. Our company is built on a foundation of principles that include responsibility to the communities we serve and where we live and work. In 2008, we launched a Corporate Citizenship Initiative, a global effort to address the environmental, social, economic, and ethical challenges we face in our business. Among the issues we are addressing...
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...Cogon Grass as Thermal Insulator In: Science Cogon Grass as Thermal Insulator COGON GRASS AS THERMAL INSULATING MATERIAL KRISELLE ANNE A. GERPACIO A Thesis Outline Submitted to the Department of Civil Engineering, College of Engineering and Computing, University of Southern Mindanao, Kabacan, Cotabato in Partial Fulfillment of the Requirements for the Degree of BACHELOR OF SCIENCE IN CIVIL ENGINEERING DECEMBER 2014 INTRODUCTION Significance of the Study Cogon grass known as Imperata cylindrical is considered as the one of the worst weed because it destroys the land where it grows. It deteriorates the nutrients of the soil thus creating problems to farmers. Hence, the researcher would like to study if this grass can be a substitute as thermal insulating material. If it can be an alternative, this research would really give great help to many farmers. Objectives of the Study The main objective of this study is determine whether Cogon grass can be a substitute as thermal insulator as compared to other traditional thermal insulating materials. Specifically, this study aims to: 1. determine the thermal resistance (R) of Cogon grass as thermal insulating material; 2. determine the thermal conductivity (k) of Cogon grass as thermal insulating material; 3. determine how much heat (Q) trasmit to the layer of the Cogon grass per second; and, 4. determine how much is the temperature gradient or temperature difference per unit thickness of...
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...ABSTRACT Thermodynamics is the science of heat and temperature and, in particular, of the laws governing the conversion of thermal energy into mechanical, electrical, or other forms of energy. It is a central branch of science that has important applications in chemistry, physics, biology, and engineering. What makes thermodynamics such a powerful tool? It is a completely logical discipline and can be applied without any sophisticated mathematical techniques. The immense practical value of thermodynamics lies in the fact that it systematizes the information obtained from experiments performed on systems and enables us to draw conclusions, without further experimentation, about other aspects of the same systems and about similar aspects of other systems. It allows us to predict whether a certain reaction will proceed and what the maximum yield might be. Thermodynamics is a macroscopic science concerning such properties as pressure, temperature, and volume. Unlike quantum mechanics, thermodynamics is not based on a specific molecular model, and therefore it is unelected by our changing concepts of atoms and molecules. Indeed, the major foundations of thermodynamics were laid long before detailed atomic theories became available. This fact is one of its major strengths. Furthermore, thermodynamics helps us predict the direction and extent of chemical reactions; it tells us nothing about the rate of a process. First Law of Thermodynamics Introduction The first law of conservation...
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...Heat Transfer Course Paper Name Institution Date Introduction To explore and work in space, the astronauts must carry their environment because there is no oxygen and atmospheric pressure to sustain life. The spacesuit is more than clothes an astronaut puts on in space. It’s really a small spacecraft. Its main work is to protect the astronaut when in space. Astronauts needs to put on spacesuits at any time they leave a spacecraft and are exposed to the surrounding space. In space, air to breath and air pressure is not available. Space has dangerous radiation and is extremely cold so without protection, an astronaut would rapidly die in space. The design of spacesuits is such that it protect astronauts from the radiation, cold and low pressure in space and furthermore provide air to breathe. Wearing a spacesuit permits an astronaut to be able survive and work in space. They also keep the astronaut from getting hurt by the space dust. The space dust always travel at a very high speed and may cause hurt to the astronaut. Moreover the suits holds drinking water for the astronaut. The spacesuit is made up of many parts that perform different roles. One of the parts protect the chest, another part covers the arms and connects to gloves and the helmet protects the head. The last part of this suit covers the astronaut’s feet and legs. Other parts of this suits are made up of many layers of material. The layers each performs different roles; some protect the astronaut from space...
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...as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system. Heat conduction, also called diffusion, is the direct microscopic exchange of kinetic energy of particles through the boundary between two systems. When an object is at a different temperature from another body or its surroundings, heat flows so that the body and the surroundings reach the same temperature, at which point they are in thermal equilibrium. Such spontaneous heat transfer always occurs from a region of high temperature to another region of lower temperature, as described by the second law of thermodynamics. Heat convection occurs when bulk flow of a fluid (gas or liquid) carries heat along with the flow of matter in the fluid. The flow of fluid may be forced by external processes, or sometimes (in gravitational fields) by buoyancy forces caused when thermal energy expands the fluid (for example in a fire plume), thus influencing its own transfer. The latter process is often called "natural convection". All convective processes also move heat partly by diffusion, as well. Another form of convection is forced convection. In this case the fluid is forced to flow by use of a pump, fan or other mechanical means. Thermal radiation occurs through...
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...B.Sc. degree in environmental studies the thermal environment Dr. Marcus M. Keane, Department of Civil and Environmental Engineering, University College Cork. the thermal environment • Metabolism and comfort • Bodily mechanisms of heat transfer and thermostatic control • Metabolic rates • Clothing • Environmental influences on comfort • Fanger's comfort equation • Measuring Instruments • The choice of inside design conditions 1. metabolism and comfort [pic] Metabolism is the mechanism whereby the body converts food into different forms of energy by digesting food in the presence of oxygen. This energy takes the following forms: 1. Work 2. Thermal Energy 3. Waste products Work The amount of bodily energy converted into work is not very great - 0% for a body at rest, 20% when walking up a one in four gradient at 10km/h. Thermal Energy Most of the energy produced by the bodily metabolism is dissipated as heat to the environment. The mechanism for this is seen in the next overhead. Waste Products The remainder of the energy produced is dissipated in waste products. thermal energy Thermal energy is released through an interaction of chemical changes occurring within the body and muscular contractions. [pic] The purpose of the body's thermo-regulatory system is to keep the temperature of...
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...[pic] |Activity 1.3.3 Thermodynamics | Introduction Think back to the last time someone complained about a door being left open. What did you notice about the temperature within the room as a result of the open door? In Activity 1.3.3 you will investigate the effects of work, thermo energy, and energy on a system, as in the case of the room with the door left open. Procedure Answer the following questions as your teacher discusses the Introduction to Thermodynamics presentation. 1. Define thermodynamics. 2. List three examples of a thermodynamic system. a. b. c. 3. Define thermal energy. 4. Define temperature. |Scale |Freezing point of water |Boiling point of water | |Celsius | | | |Fahrenheit | | | |Kelvin | | | 5. Fill in the table below with the correct scale and unit. ...
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...Substances | Substance | Property | | Metal(Stainless Steel) | * Shiny hence providing the item an attractive appearance. * Good reflector of infrared radiation so the vacuum flask does not receive or lose heat from surroundings. * Malleable so that it can be beaten into required shapes. * Corrosion resistant hence it does not affect flask’s content. * - Hard and strong. This helps to protect the brittle glass. | | Plastic(Polystyrene) | * Good insulator so that heat conduction is minimized. * Impermeability. This helps to reduce the escape of heat by convection and evaporation as it provides a solid blockage. | | Glass | * Good insulator to minimize heat conduction. * Silver-coated to reflect infrared radiation from the surrounding away from the flask as well as the radiation from the contents back into flask. * High melting and boiling points. It is suitable to store hot and cold liquids. * Generally unreactive hence it is safe to store drinks. * Non-corrosive so that fluids are safe to consume. | d) Bonding and Structure | Substance | Properties | Bonding and Structure | | Metal(Stainless Steel) | Shiny | Metals consist of delocalized electrons which reflect light making metals lustrous. | | | Good Reflector of Radiation | Metals are shiny. Shiny objects are good reflector of radiation. | | | Malleable | Metals consist of free mobile electrons that are non-directional, allowing metal atoms to slide over each over without breaking...
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