   # Heat Transfer Notes

Satisfactory Essays
Topics: Heat transfer
Eb= blackbody emisibibility
= σT 4
T in K units W/m^2
E= εσT 4 qemit =EA Watts energy emitted recognize the direction qnet
Eᵬ= W/m^2 M
Radiation Amount of energy emitted from green color
10 nm 450 nm ~470 nm ∞

Eb ∫ Eᵬ, b ^dᵬ
0

E= ∫ ƐE ᵬ, b d ᵬ
0

0

2

E= ∫ ƐE ᵬ, b d ᵬ ∫ ƐE ᵬ, b d ᵬ

G Gij

⍴ ᵭ+ᵬ=1 Ɛ= Erad/ ( σT 4 ) Blackbody surface
Jb=Eb

Ji= ƐiσT 4 + ∑

Geometrical alpha = epsilon

black body surface ji­­­­­­­~~~­­­­ji Ji=Ebi Net work surface 1 node potential on )
Eb1
Eb2 eb3 connect the dots with resistors 1/A1F12
Eb1 to Eb2 net work surface 1 q1 on EB1 flows into q12 and q13 parallel q1=q12+q13 q1=energy flow from 1 to 2 and 1 to 3

three major parts outline Radiation arbitrary surface Gfi reflection pGji ƐalphaGji given part of the problem find the rest

alpha = Ɛ when exists qnet, rad =? energy conservation at steady state relationship between terms calculation problems
View factor Calculations F14=a
F12, F13, F21, F41 ect Fij sigma Fij=1
AiFij=AjFji

Fi­ l +m = Fil + Fim Ji Gij qij

i, Ji, Ai

qij=(Ji­Jj)/(1/AiFij) blackbody
Ji=Ei(T)

function of temperature Radiation network to find flux or potential 40 to 50 % ison radiation Heat exchanger
U fouling factor will increase the resistance of heat transfer. how to include into the overall equation (mcp)h Th, in Tc, out
(mcp)c Tc,in You want to know the cooling effect energy conservation Q= {mcp(Th,i­Th,o)}h
={mcp(Tc,o­Tc,i) }c Delta Tlm log mean difference Q=UA DTcm Q=HA Dt

A=Q/(U delta T) 2pirL Delta Tlm’= DeltaTlm*F
NTU
effectiveness
Ɛ­NTUmethod
Ɛ=?(Q/Qmax) NTU= UA/mcpmin qmax/Qmax design the amount of heat exchange required for a problem eplison is known NTU =UA/ mcpmin Length of a pipe thermal analysis NTU ­> eplison

## You May Also Find These Documents Helpful

• Satisfactory Essays

Lectures Lectures of Heat Transfer Heat Transfer Rate Processes Mode Conduction Convection Radiation Transfer Mechanism Diffusion of energy due to random molecular motion Diffusion of energy due to random molecular motion plus bulk motion Energy transfer by electromagnetic waves Rate of heat transfer (W) q = - kA dT dx q = h A(Ts-T∞) q = σ ε A(Ts4-Tsur4) By Mr. Amjed Ahmed Ali Syllabus of Heat Transfer (English), (2 hours/ week, Applied 2 hours /week) 1.Heat transfer by conduction, convection…

• 12359 Words
• 50 Pages
Satisfactory Essays
• Satisfactory Essays

Mechanisms of Heat Transfer Prepared by: Ms. Ana Antoniette C. Illahi 1 Conduction • conduction (or heat conduction) is the transfer of thermal energy between regions of matter due to a temperature gradient. Heat spontaneously flows from a region of higher temperature to a region of lower temperature, and reduces temperature differences over time, approaching thermal equilibrium. Prepared by: Ms. Ana Antoniette C. Illahi 2 (Heat Current in Conduction) • • • • • • • • H - Heat Current…

• 708 Words
• 3 Pages
Satisfactory Essays
• Satisfactory Essays

The University of Sydney Aerospace, Mechanical and Mechatronic Engineering MECH3260 Thermal Engineering Heat Transfer Quiz 3 2007 Time: 40 minutes Answer ONE question only. Question 1 Consider the cylindrical receiver in a solar thermal power plant shown below. The receiver is made of opaque material and has a diameter D = 8m and length L = 14m. At a particular time, the heliostats direct a concentrated solar flux of q”S = 80 kW/m2…

• 418 Words
• 2 Pages
Satisfactory Essays
• Good Essays

Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy and heat between physical systems. Heat transfer is classified into various mechanisms, such 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…

• 636 Words
• 3 Pages
Good Essays
• Better Essays

Heat transfer Heat transfer is the transition of thermal energy from a hotter object to a cooler object ("object" in this sense designating a complex collection of particles which is capable of storing energy in many different ways). When an object or fluid is at a different temperature than its surroundings or another object, transfer of thermal energy, also known as heat transfer, or heat exchange, occurs in such a way that the body and the surroundings reach thermal equilibrium, this means that…

• 4676 Words
• 19 Pages
Better Essays
• Good Essays

HEAT TRANSFER Heat transfer, also known as heat flow, heat exchange, or simply heat, is the transfer of thermal energy from one region of matter or a physical system to another. When an object is at a different temperature from its surroundings, heat transfer occurs so that the body and the surroundings reach the same temperature at thermal equilibrium. Such spontaneous heat transfer always occurs from a region of high temperature to another region of lower temperature, as required by the second…

• 777 Words
• 4 Pages
Good Essays
• Powerful Essays

MECH 4010 Design Project Vertical Axis Wind Turbine Group 2 Jon DeCoste Denise McKay Brian Robinson Shaun Whitehead Stephen Wright Supervisors Dr. Murat Koksal Dr. Larry Hughes Client Department of Mechanical Engineering Dalhousie University December 5, 2005 EXECUTIVE SUMMARY With the recent surge in fossil fuels prices, demands for cleaner energy sources, and government funding incentives, wind turbines have become a viable technology for power generation. Currently, horizontal…

• 10289 Words
• 42 Pages
Powerful Essays
• Good Essays

Chapter 15 & 16: Temperature, Heat & Heat Transfer Temperature is a measure of the average (not total) translational kinetic energy. ●ex: there is 2x as much total molecular kinetic energy in a 2L of boiling water than one, but the temp of the two volumes are the same (average of translational kinetic energy per molecule is the same in each → Internal Energy- the total of all molecular energies: kinetic+potential (SAME TEMP) ● Ex: apply a flame to 1L h2o for a certain time and its temp rises…

• 3471 Words
• 14 Pages
Good Essays
• Better Essays

DEFINITION OF HEAT TRANSFER | Heat transfer is energy in transit due to temperature difference . Whenever there exists a temperature difference in a medium or between media, heat transfer must occur. The basic requirement for heat transfer is the presence of temperature difference . There can be no net heat transfer between two mediums that are at the same temperature. The temperature difference is the driving force for heat transfer, just as the voltage difference is the driving force for electric…

• 1205 Words
• 5 Pages
Better Essays
• Good Essays

FUNDAMENTAL CONCEPTS Heat transfer is energy in transit, which occurs as a result of temperature gradient or difference. This temperature difference is thought of as a driving force that causes heat to flow. The concepts of heat transfer and temperature, the key words in the discipline of heat transfer, are 2 of the most basic concepts of thermodynamics. dffffffffff rifffff orfff ffffffffff fv ing ff ce Rate of transport process= fffffffffff or rate = coefficient B driving force resist…

• 9919 Words
• 40 Pages
Good Essays