...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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...Table of Contents Abstract 2 Introduction 2 The Fire Problem 2 Methodology 5 Results and discussion 6 Processes of flame spread 7 Diffusion flame spread 8 Thermal Model 8 Transition to Turbulence 10 References 13 Abstract The fires problem is one of the hazard pose a threat to life and property. Flames behave differently under various conditions which include: the oxygen available, combustible material, orientation of surfaces, etc. this a complex phenomena which is influenced by multiple factors that includes ignition, heat release rate, flame spread and the generation of different products of combustion like carbon IV oxide and carbon II oxide. The research was performed by studying various sources in the library and in the internet and also performing experiments to simulate a real life situation. Introduction The Fire Problem The flammability of a material is a complex event which is influenced by multiple factors that includes ignition, heat release rate, flame spread and the generation of different products of combustion like carbon IV oxide and carbon II oxide. In order to better protect the people and property from risk posed by the unwanted fires, it become necessary to understands all these factors under different conditions. Babrauskas and Vytenis 1992 suggested that heat release rate is the main variable in fire hazard; but Kashiwagi and Ito argued effectively that, the flame spread over the surface...
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...Chapter 1 INTRODUCTION The project ‘Heat Transfer Studies on a 7.5 Watt LED Lighting Load using Finite Element Analysis’ is mainly concerned with the heat generated by an LED lighting load and its dissipation to the surrounding such that the LED junction temperature is maintained low. The LED chosen for this project is 7.5 Watt, which has a maximum operating temperature of around 80°C, exceeding which the LED will fail. The LED is best operated at room temperature conditions and may be just above. The project implements a specific method of cooling or rather maintaining the LED junction temperature as low as possible by using a Thermo Electric Cooling device, more specifically known as the Peltier device. The project looks into the various methods by which a Peltier cooler can be implemented such as, with or without a fan or simply a fan would provide sufficient cooling for the LED module. A Heat sink is a necessary component which is always associated with cooling electronic components. Before getting into the depth of the project detailing we will look into the basic components that have been used in the project setup which include: a. LED Module b. Peltier Cooler c. Heat Sink d. Cooling Fan 1.1 Light Emitting Diode: Light-emitting diodes (LEDs) are small but powerful devices in terms of their diverse applications. LED lights assume greater significance in the context of need for electrical energy conservation and pollution control world over. LED is basically...
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...CHAPTER – 1 Introduction:- Heat exchangers are very helpful in chemical process, engineering application and also in daily use applications, such as, dairy industry, chemical industry, environment engineering, power production, air conditioning and also in food industry. Shell & Tube heat exchanger is commonly used in energy industries and petrochemical industry. Plate Heat Exchanger is commonly used in a wide range of chemical process and so many industrial functions. So many effort have been made to increase the heat transfer of heat exchanger, reduce the heat transfer time and also increase the energy utilization. The mixture of fluid (base liquid) and Nanoparticles (nanometer sized) are called 'nanofluid'. Latest technology gives benefit...
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...Method and theory of 3D micro heat pipe cooling introduction: The traditional heat dissipation method has included different parts, such as Air cooling and Water cooling. When IC chip generate heat in working on a high level, there has to be some methods to reduce heat make sure that the chips will not be damaged. With some theory [Surface area of evaporator, Heat input in Watt act.] there are several advanced method and theory of 3D micro heat pipe cooling. Key word: LPMHP, Tube transfer ,Moore's Law ,Heat-Pipe, Fluids, Cooling rate. Method and theory in experimental A experimental study has been performed to investigate the heat transfer characteristics of looped parallel micro heat pipes of circular geometry having inner diameter of 1.8mm and length of 150mm placed parallel, connected by two U tubes of same diameter at the top and bottom ends. The experimental parameters are condenser inclination angel, heat input and properties of the working fluids. Taking acetone and ethanol as working fluids, heat transfer characteristics are determined experimentally for different condenser inclination angels a different heat input. With the advancement of micro and nanotechnologies, the power densities in the electronic equipments are increasing rapidly. Overheating of integrated circuit(IC),microchip etc. It is very important to facilitate optimum cooling of electronic components in a smaller electronic device because integrated circuit lifetime depends...
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...needed to be optimized in building envelop. Extended Research Task Temperature Control in Homes ---- Windows Extended Research Task Temperature Control in Homes ---- Windows Temperature Control in Homes --- Windows 1. Abstract: The window insulation always plays an important role in building design and thermal comfort, it is one of the main parts needed to be optimized in building envelop. Window insulation is a basic element which can decide the insulation capacity. The large heat loss from the window is the main part of wasting energy, and simultaneously, there is also difficult to explore the new energy source and to improve the current heat generation device efficiency. Therefore, building a proper insulated window system is a good approach to keep an acceptable indoor climate as well as to reduce energy use and negative climate effects. The aim of this extended research task is to introduce readers to different ways of windows insulation that can efficiently reduce heat loss in an average household during Tasmanian winter. 2. Introduction Tasmania has cold temperature climate with four distinct seasons, with the most distinctive season during the winter month between June and July. During the winter season Tasmania become the wettest and coolest state in Australia with most high lying areas receiving considerable snowfall. Winter maximums are 12 °C (54 °F) on average along coastal areas and 3 °C (37 °F) on the Central Plateau, thanks to a series of...
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...LABORATORY 2 ME 11L SUBMITTED BY: Alega, Ulysses Jr. H. Bicaldo, Mark Zedrick L. Engaño, Moises A. Sabida, Ricalyn B. SUBMITTED TO: Engr. Manuel E. Europeo March 10, 2014 INTRODUCTION Heat conduction (or thermal conduction) is the transfer of internal energy by microscopic diffusion and collisions of particles or quasi-particles within a body due to a temperature gradient. The microscopically diffusing and colliding objects include molecules, electrons, atoms, and phonons. They transfer disorganized microscopic kinetic and potential energy, which are jointly known as internal energy. Conduction can only take place within an object or material, or between two objects that are in direct or indirect contact with each other. Conduction takes place in all forms of ponderable, such as solids, liquids, gases and plasmas. Whether by conduction or by thermal radiation, heat spontaneously flows from a hotter to a colder body. In the absence of external drivers, temperature differences decay over time, and the bodies approach thermal equilibrium. In conduction, the heat flow is within and through the body itself. In contrast, in heat transfer by thermal radiation, the transfer is often between bodies, which can be spatially separate. Also possible is transfer of heat by a combination of conduction and thermal radiation. In convection, internal energy is carried between bodies by a material carrier. In solids, conduction is mediated by the combination of vibrations and...
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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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...CHAPTER 4 SI UNIT PROBLEMS SOLUTION MANUAL SONNTAG • BORGNAKKE • VAN WYLEN FUNDAMENTALS of Thermodynamics Sixth Edition Sonntag, Borgnakke and van Wylen CONTENT SUBSECTION Correspondence table Concept problems Force displacement work Boundary work: simple one-step process Polytropic process Boundary work: multistep process Other types of work and general concepts Rates of work Heat transfer rates Review problems English unit concept problems English unit problems PROB NO. 1-19 20-30 31-46 47-58 59-70 71-81 82-94 95-105 106-116 117-122 123-143 Sonntag, Borgnakke and van Wylen CHAPTER 4 6 ed. CORRESPONDANCE TABLE The new problem set relative to the problems in the fifth edition. New 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 5th 1 2mod new New New 3 4 new New new New New 18 27 new new 5 new New 13 new new New New New 22 45 mod 8 12 14 New New New New 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 5th new 19 20 33 mod 37 36 15 30 6 New 32 7 9 34 10 New New 26 39 New 40 New New New New 58 59 60 61 New New New New New 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 5th new new new 43 new New new new New 47 HT 48 HT 49 HT 50 HT mod 51 HT mod 52 HT 53 HT 54 HT 55 HT 56 HT 57 HT 31 mod 11 16 17 23 21 mod 28 29 24 44 35 th Sonntag, Borgnakke and van Wylen The English unit problem set is New...
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...partan Heat Exchangers Inc. Group Case Study Spartan Heat Exchangers Inc. Current State Spartan Heat Exchangers Inc. has been a leading designer and manufacturer of specialized industrial heat transfer equipment for more than 10 years. The company’s primary products are transformer coolers, hydro generator coolers, air-cooled heat exchangers and transformer oil coolers. Their USP are Fin tube type heat exchangers and long lasting products. “… A heat exchanger is a device that is used to transfer thermal energy (enthalpy) between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. …” The company is into highly customized heat equipments. Presently, due to entry of new competition from European and Korean companies they have changed their corporate policy, which emphasize on reducing the variety and standardizing the product. The new business policy also aims at reducing the current lead time from 14 weeks to 6 weeks. Problem Statement The Materials Department headed by Rick Coyne has to take many initiatives internally to incorporate the various implications of the new strategy, and submit his report to his boss Max Brisco with the changes suggested by him within a week. The major challenges that Rick faces include: • Change from responsive to anticipatory model of production. • Increase inventory turns from present 4 times to 20 times. • Eliminate material shortages...
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...ZECCHIN Dott. Ing. Michele DE CARLI Dott. Ing. Dietrich SCHMIDT Laureando: Alessio PULLIERO Anno accademico 2003-2004 To my parents …. ABSTRACT The main purpose of this thesis is to investigate different control strategies for the heating and cooling system of the ZUB (Centre for Sustainable Building), situated in Kassel, Germany. It is an experimental office building, with a very detailed monitoring system for studying low-energy and low-exergy building technologies. The conditioning system is a TABS (Thermally Activated Building System), with water pipes embedded in the centre of a structural concrete slab, thus resulting in a ceiling radiant system. The high thermal capacity of the slab offers great opportunities to store heat, to dampen temperature fluctuations or to shift the peak-load; but, on the other hand, it implies a slow response of the system, which requires an accurate regulation strategy to front the variability of several factors, and to achieve the desired indoor temperature. A TRNSYS model of an office room has been developed, thus allowing to implement several regulations in the software and to test their performance. The main conclusion, carried out from the simulations, is that the implementation of a Feed-forward controller gives appreciable advantages in the temperature control, achieving both a more precise control of thermal conditions and a reduction of the energy consumption. The parameters taken into account by the controller are more than...
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...Transient, One-Dimensional Heat Conduction in a Convectively Cooled Sphere Gerald Recktenwald∗ March 16, 2006† 1 Overview This article documents the numerical evaluation of a well-known analytical model for transient, one-dimensional heat conduction. The physical situation is depicted in Figure 1. A sphere of uniform material is initially at a uniform temperature Ti . At time t = 0 the sphere is immersed in a stream of moving fluid at some different temperature T∞ . The external surface of the sphere exchanges heat by convection. The local heat flux from the sphere to the fluid is q = h(Ts − T∞ ) (1) where h is the heat transfer coefficient, and Ts is the local surface temperature. The problem is greatly simplified by assuming that the heat flux on the surface is uniform. Under this condition, Ts = T (r0 ) is also uniform and the temperature inside the sphere depends only on the radius, r, and time t, i.e., ∗ Mechanical and Materials Engineering Department, Portland State University, Portland, OR, 97201, gerry@me.pdx.edu † Corrections made 10 September 2011 h T ro Figure 1: A sphere immersed in and exchanging heat with stream of fluid. 1 2 T = T (r, t). The temperature field is governed by the heat equation in spherical coordinates ∂T α∂ 1 ∂T =2 (2) ∂t r ∂r r2 ∂r where α = k/(ρc) is the thermal diffusivity of the sphere material, k is the thermal conductivity, ρ is the density, and c is the specific heat. The boundary condition on the surface is k ∂T ∂r = h(T∞ − Ts ). (3) r =r0...
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...trODuct ION tO G rO u N D S O u rc e Heat P uMP SyS teM S chris arkins This note TEC 6, originally published in February 1999, was reviewed by Chris Arkins in January 2004. This summary page includes recent updates to the topic since publication. SUMMARY OF actIONS tOwarDS SuStaINable OutcOMeS Introduction Alternative low energy air conditioning solutions are now commonly sought in preference to typical air conditioning systems for both residential and commercial applications. The industry has seen a growing emergence of ground source heat pump (GSHP) installations throughout Australia over the last five years. A broad spectrum of facilities ranging from domestic housing, hospitals, education facilities, commercial offices and civic buildings to name a few, are now realising the environmental benefits offered by GSHP systems over more commonly used air conditioning systems. This summary note provides a brief overview of the previous note and provides an update on changes that have occurred since. basic Strategies Heat rejection is fundamental to all air conditioning systems. Typically, unsightly roof mounted air cooled condensers and cooling towers are by far the most commonly used method for rejecting heat from a building. Ground source heat pumps are somewhat different to the norm. Basically GSHP are refrigeration machines that provide heating and cooling by using ground water and the earth as a medium to reject and/or absorb heat and as such do not require air cooled...
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...are made up of methane, ethane, propane and nitrogen (Shukre,F and Wheeler,F 2004 pg 3). Firstly, the natural gas (fed stream) comes in from the top and goes through three mixed refrigerants cycles (red stream). The pre-cooling cycle (green stream) consists of a mixture of Methane and Propane which is compressed in C1 according to the below diagram. It then is liquefied (purple stream) in sea water cooler C1 and sub cooled (blue stream) in E1A (Forg,W, Bach,W, Stockmann,R… 1999 pg5). One part is then throttled to an intermediate pressure and used as refrigerant in E1A. The other part is further sub cooled in heat exchanger E1B, throttled to the suction pressure of compressor C1 and used as refrigerant in E1B(Forg,W, Bach,W, Stockmann,R… 1999 pg5). The liquefaction cycle is compressed in C2, cooled in sea water cooler CW2A/2B. It is then further cooled in heat exchanger E1A, E1B and E2 (Forg,W, Bach,W, Stockmann,R… 1999 pg5). It is then throttled...
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...of the secondary fluid to the heat exchanger may change with time. This means that in order to maintain a consistent secondary fluid outlet temperature, the heat supplied to the heat exchanger must also vary. This can be achieved by using a control valve on the inlet to the primary side of the heat exchanger, as shown in Figure 13.2.1. Fig. 13.2.1 Typical temperature control of a steam/water shell and tube heat exchanger A control valve is used to vary the flowrate and pressure of the steam so that the heat input to the heat exchanger can be controlled. Modulating the position of the control valve then controls the outlet temperature of the secondary fluid. A sensor on the secondary fluid outlet monitors its temperature, and provides a signal for the controller. The controller compares the actual temperature with the set temperature and, as a result, signals the actuator to adjust the position of the control valve. For a constant heating area and heat transfer coefficient, the rate at which heat is transferred from the steam to the secondary fluid for a particular heat exchanger is determined by the mean temperature difference between the two fluids. A larger difference in mean temperatures will create a large heat transfer rate and vice versa. On partially closing the control valve, the steam pressure and the temperature difference fall. Conversely, if the control valve is opened so that the steam mass flow and hence pressure in the heat exchanger rise, the mean temperature...
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