Tong quan ve truyen nhiet - DH CN.PDF

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<ul><li><p>Ly Ngoc Minh, Senior Lecturer 1</p><p>TRNG AI HOC CONG NGHIEP TPHCMKHOA CONG NGHE HOA HOC VA MOI TRNG</p><p>CHNG ITNG QUAN V TRUYN NHIT</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 2</p><p>VAI TRO CUA TRUYEN NHIET</p><p>MY HI NC THI C I</p><p>ong c hi n cthi Hy-lap coai</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 3</p><p>Mt hnh nh TB Nhit trong thc t</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 4</p><p>Cu hi tho lun: cho bit nhng hnh thctrao i nhit xy ra trong hnh nh ny?</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 5</p><p>Hy m t cc qu trnh TN xy ra trong hnhnh di y?</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 6</p><p>NOI HI ONG LO ONG LA NAM</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 7</p><p>TRUYN NHIT</p><p>NHIT BAO GI CNG CTRUYN T NI C NHIT CAON NI C NHIT THP.</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 8</p><p>3 DNG TRAO I NHIT C BN</p><p>DN NHITDN NHIT</p><p>BC X NHITBC X NHIT</p><p>I LU NHITI LU NHIT</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 9</p><p>The Nature of Heat</p><p> Definition: Heat is the internal kinetic energy ofthe atoms and molecules that make up asubstance. Since it is a form of energy, it is measure in thestandard unit of a Joule.</p><p> More commonly, it is measured in the following units: calorie heat energy needed to raise 1 gram of water by 1degree Celsius. 1 calorie = 4.186 Joules.</p><p> Calorie commonly used to measure energy content of food.1 Calorie = 1000 calories.</p><p> British Thermal Unit (BTU) heat energy needed to raiseone pound of water by 1 degree Fahrenheit. 1 BTU = 252calories = 1,054 Joules.</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 10</p><p>Properties of Heat</p><p> Two liters of boiling water has more energythan one one liter of boiling water.</p><p> Heat will not flow between two objects of thesame temperature.</p><p> Heat is energy in the process of beingtransferred from one object to another becauseof the temperature difference between them</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 11</p><p>Heat Capacity</p><p> Definition: Heat capacity is the amount of heatrequired per unit increase in temperature. It is a measure of how well the substance stores heat. Heat added = heat capacity x (change in temperature) Materials with large heat capacities hold heat well.</p><p> Their temperatures will not rise much for a given amount ofheat.</p><p> Example: water</p><p> Materials with small heat capacities do not hold heatwell. Their temperatures will rise quickly for a given amount ofheat</p><p> Example: air</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 12</p><p>Mechanisms of Heat Transfer</p><p> Conduction Convection Advection Radiation</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 13</p><p>Conduction</p><p> Conduction is the transfer of heat within asubstance, molecule by molecule</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 14</p><p>TRUYN NHIT DN NHIT</p><p>T1</p><p>T2</p><p>d</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 15</p><p>TRUYN NHIT DN NHIT</p><p>DT1 DT2 DT3</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 16</p><p>Conductivity of Various Substances</p><p>427Silver80Iron2.7Granite2.1Ice2.1Wet Soil0.63Snow0.60Water at 20 C0.25Dry Soil0.023Still air at 20 CHeat ConductivitySubstance</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 17</p><p>Convection</p><p> Convection is heat transfer by the movement ofa fluid in the vertical direction</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 18</p><p>Advection</p><p> Advection is the movement of heat in thehorizontal (north/south/east/west) direction.</p><p> Any measurable property of air can beadvected.</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 19</p><p>TRUYN NHIT I LU</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 20</p><p>Khi nim v tun han</p><p>HI RA</p><p>NC CAP</p><p>O NGN</p><p>C</p><p>X UO NG</p><p>ONG NC LENONG NC XUONG</p><p>S lun chuyn canc trong ni hi</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 21</p><p>Radiation</p><p> Radiation allows heat to be transferred throughwave energy</p><p> These waves are called electromagnetic wavesbecause the energy travels in a combination ofelectric and magnetic waves</p><p> The energy a wave carries is related to itswavelength (distance from crest to crest)</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 22</p><p>Electromagnetic Spectrum</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 23</p><p>Stephan-Boltzmann Law</p><p> All things with a temperature above absolute zero emitradiation.</p><p> As the temperature of an object increases, moreradiation is emitted each second</p><p>E = T4</p><p>where is a constant, T is the temperature of an objectin Kelvin and E is the maximum rate of radiationemitted per square meter.</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 24</p><p>Weins Law</p><p> Weins law states that the wavelength of maximumemission of an object is related to the objectstemperature.</p><p>max = /Twhere max is the wavelength in micrometers (m) atwhich the maximum radiation emission occurs, is aconstant equal to 2897 m K, and T is the temperaturein Kelvin.</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 25</p><p>Emission Spectrum ofan Object with</p><p>Constant Temperature</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 26</p><p>Summary</p></li><li><p>Ly Ngoc Minh, Senior Lecturer 27</p><p>Weins Law</p><p> Weins law states that the wavelength of maximumemission of an object is related to the objectstemperature.</p><p>max = /Twhere max is the wavelength in micrometers (m) atwhich the maximum radiation emission occurs, is aconstant equal to 2897 m K, and T is the temperaturein Kelvin.</p></li></ul>