HEAT TRANSFER IM LECTURE HOURS PER WEEK THERMODYNAMICS - IM _1

Transcription

1 COURSE CODE INTENSITY PRE-REQUISITE CO-REQUISITE CREDITS ACTUALIZATION DATE HEAT TRANSFER IM05 LECTURE HOURS PER WEEK 8 HOURS CLASSROOM ON 6 WEEKS, HOURS LABORATORY, HOURS OF INDEPENDENT WORK THERMODYNAMICS - IM07 NONE 0_ JUSTIFICATION Heat is a form of energy transfer that is always present in the processes occurring in the world, so it is important that mechanical engineers learn the basics for the management and control of heat in all processes and equipment, and in technical systems in general that they will find in the exercise of their profession and in life in general. To estimate the cost, the feasibility, and the size of equipment necessary to transfer a specified amount of boilers, heaters, refrigerators, and heat exchangers depends not only on the amount of heat to be transmitted but also on the rate at which the heat is to be transferred under given conditions. The successful operation of equipment components such as turbine blades, or the walls of combustion chambers, depends on the possibility of cooling certain metal parts by continuously removing heat from a surface at a rapid rate. A heat transfer analysis must also be made in the design of electric machines, transformers, and bearings to avoid conditions that will cause overheating and damage the equipment. INTRODUCTION The heat transfer course seeks to empower the future mechanical engineer with the basic tools to design equipment that harness the energy as heat. It s an introductory course focuses in the basic principles of the phenomena of heat transfer and how to apply them in the design of equipment and goods for human use, taking in mind technical, economical, and environmental aspects. The course is divided in four modules. The first one introduces the basic modes of heat transfer. A second modulo is dedicated to the analysis of Heat Exchangers, an

2 equipment that give a broad perspective of the three basic modes before going in to the details of them. Finally, a full modulo is dedicated to each of the basic modes of heat transfer, conduction, convection, and radiation. The course includes some practices in lab and a project that help students to achieve the program goals. The prerequisites for this course are undergraduate courses in basic mathematics, thermodynamics and fluid mechanics. GENERAL AIM OF THE COURSE To develop the skills to model heat transfer processes in technical systems and provide answers to issues related to certain conditions of heat flow, temperature distributions, or rates required for heating or cooling, as well as some methods to design thermal equipment. SPECIFIC AIMS OF THE COURSE To understand the concepts and laws governing heat transfer by conduction, convection and radiation To be familiar with charts and graphs required to calculate heat fluxes and temperature distributions in some systems. To understand the bases to select and design heat exchangers. GENERAL CONTENTS Introduction Basic Modes of Heat Transfer Heat Exchangers Heat Transfer by Conduction Heat Transfer by Radiation Analysis of Convection Heat Transfer Lab Practices Measurement of temperature and pressure The calorific power of fuels Analysis of combustion products Determination of steam properties Heat conduction in plates and cylinders Free or natural convection, and forced convection in horizontal and vertical flat plates Fins Heat exchangers Cooling towers

3 METODOLOGY Teacher exposure topics. Work in the classroom by students with the guidance of Professor or monitor for the solution of the workshops and the suggested exercises. Work outside the classroom by the student solving related problems. Work in the laboratory in charge of the student and teacher-oriented laboratory for conducting experiments. EVALUATION Basic Modes of Heat Transfer + Heat 5% st exam Exchangers 0% nd exam Heat Transfer by Conduction 5% rd exam Heat Transfer by Radiation 0% Lab Practices 0% Final exam Analysis of Convection Heat Transfer REFERENCES Books TEXT GUIDE Kreith F., Bohn M. Principles of Heat Transfer. 6ª. Ed. Thomson Learning Other books Karlekar and Desmond, Engineering Heat Transfer Incropera, Fundamentals of Heat Transfer Holman, Heat Transfer Kern, Process Heat Transfer

4 WEEKLY SYLLABUS AND STUDENT WORK Week Topics Text Guide Section Introduction (.5h) Introduction The Relation of Heat Transfer to Thermodynamics. Heat and Other Forms of Energy the first law of thermodynamics Dimensions and Units Basic Modes of Heat Transfer (6h) Heat Exchangers (6h) Heat conduction Fourier s law of Conduction Plane, Cylindrical and Spherical Walls Thermal conductivity and Thermal diffusivity Analogy Between Heat Flow Systems Electric Circuits. Convection Heat Transfer The Newton s law of cooling Natural and Forced convection Radiation Heat Transfer The Stefan Boltzmann Law The Kirchhoff's Law The Combined Heat Transfer Coefficient Combined Modes of Heat Transfer Thermal Resistances in Series and in Parallel Contact or Interface Resistance Critical Radius of Insulation Types and Description of Heat Exchangers Overall Heat Transfer Coefficients and the Fouling Resistances Heat Exchanger Analysis The Log-Mean Temperature Difference (LMTD) method the Number of Transfer Units (NTU) method Heat Exchanger Selection and Sizing 5 Partial Preparation 5 st PARTIAL EXAM 6 Heat Transfer by Conduction (0.5) The General Equation of Heat Conduction boundary and initial conditions one-dimensional heat conduction problems - 7 Two and Three-Dimensional Steady State Conduction -5 7 Heat Transfer From a Fin - 8 Transient Heat Transfer -6 8 Transient Heat Conduction in Large Plane Walls, Long Cylinders, and Spheres 9 Transient Heat Conduction in Multidimensional Systems 9 Partial Preparation

5 9 nd PARTIAL EXAM 0 0 Heat Transfer by Radiation (7.5h) Basic Principles of Thermal Radiation Blackbody Radiation (Laws) Radiation Intensity Radiation Properties Environmental and Solar Radiation (reading) The View Factor View Factor Relations 9-, 9- Radiation Heat Transfer Between Black Surfaces 9-5 Radiation Heat Transfer Between Diffuse, Gray Surfaces Radiation Shields and the Radiation Effects (reading) Partial Preparation rd PARTIAL EXAM 5 Analysis of Convection Heat Transfer (9h) Mass Momentum Energy Conservation Equations Dimensional Analysis and Normalized equations Analogy between Convective Heat and Mass Transfer Forced Convection External Flows Fluid Flowing Parallel to a Flat Plate Flow over Cylinders and Spheres Heat Transfer across Tube Banks Forced Convection Internal Flows Considerations (mean fluid temperature and average velocity of the fluid) General analysis Laminar Flows Turbulent Flows Natural Convection Mechanisms of Natural Convection The movement Equation Natural Convection, Dimensional Analysis Example Calculations 5 Final Exam Preparation 6 FINAL EXAM , ,