Heat and Mass Transfer: Fundamentals and Applications
5th Edition
ISBN: 9780073398181
Author: Yunus A. Cengel Dr., Afshin J. Ghajar
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 1, Problem 37CP
Why is the thermal conductivity of superinsulation order of magnitude lower than the thermal conductivity of ordinary insulation?
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Chapter 1 Solutions
Heat and Mass Transfer: Fundamentals and Applications
Ch. 1 - How does the science of heat transfer differ from...Ch. 1 - What is the driving force for (a) heat transfer,...Ch. 1 - Prob. 3CPCh. 1 - How do rating problems in heat transfer differ...Ch. 1 - What is the difference between the analytical and...Ch. 1 - Prob. 6CPCh. 1 - What is the importance of modeling in engineering?...Ch. 1 - When modeling an engineering process, how is the...Ch. 1 - On a hot summer day, a student turns his fan on...Ch. 1 - Consider two identical rooms, one with a...
Ch. 1 - An ideal gas is heated from 50C to 80C (a) at...Ch. 1 - Prob. 12CPCh. 1 - What is heat flux? How is it related to the heat...Ch. 1 - What are the mechanisms of energy transfer to a...Ch. 1 - A logic chip used in a computer dissipates 3 W of...Ch. 1 - Consider a 150-W incandescent lamp. The filament...Ch. 1 - A 15-cm-diameter aluminum ball is to be heated...Ch. 1 - Prob. 18PCh. 1 - Prob. 19PCh. 1 - A 60-gallon water heated is initially filled with...Ch. 1 - Prob. 21PCh. 1 - Prob. 22PCh. 1 - Prob. 23PCh. 1 - Prob. 24PCh. 1 - Prob. 25PCh. 1 - Prob. 26PCh. 1 - Prob. 27PCh. 1 - Prob. 28PCh. 1 - A 5-m6-m8-m room is to be heated by an electrical...Ch. 1 - Prob. 30PCh. 1 - Prob. 31PCh. 1 - Air enters the duct of an air-conditioning system...Ch. 1 - Define thermal conductivity, and explain its...Ch. 1 - Prob. 34CPCh. 1 - Which is a better heat conductor, diamond or...Ch. 1 - How do the thermal conductivity of gases and...Ch. 1 - Why is the thermal conductivity of superinsulation...Ch. 1 - Why do we characterize the heat conduction ability...Ch. 1 - Prob. 39CPCh. 1 - What are the mechanisms of heat transfer? How are...Ch. 1 - Write down the expression for the physical laws...Ch. 1 - How does heat conduction differ from convection?Ch. 1 - Does any of the energy of the sun reach the earth...Ch. 1 - How does forced convection differ from natural...Ch. 1 - What is the physical mechanism of heat conduction...Ch. 1 - Consider heat transfer a windowless wall of house...Ch. 1 - Consider heat loss through two walls of house on a...Ch. 1 - Consider two houses that are identical except that...Ch. 1 - Consider two walls of a house that are identical...Ch. 1 - Define emissivity and absorptivity. What is...Ch. 1 - What is a blackbody? How do real bodies differ...Ch. 1 - A wood slab with a thickness 0.05 m is subjected...Ch. 1 - Prob. 53PCh. 1 - The inner and outer surfaces of a 0.5-cm thick...Ch. 1 - Prob. 55PCh. 1 - Prob. 56PCh. 1 - The north wall of an electrically heated home is...Ch. 1 - Prob. 58PCh. 1 - Prob. 59PCh. 1 - Prob. 60PCh. 1 - A concreate wall a surface area of 20 m2 and a...Ch. 1 - Prob. 62PCh. 1 - Prob. 63PCh. 1 - Prob. 64EPCh. 1 - Prob. 65EPCh. 1 - Air at 20C with a convection heat transfer...Ch. 1 - Prob. 67PCh. 1 - Prob. 68PCh. 1 - Prob. 69PCh. 1 - Prob. 70PCh. 1 - Prob. 71PCh. 1 - Prob. 72PCh. 1 - Prob. 73PCh. 1 - Prob. 74PCh. 1 - Prob. 75PCh. 1 - Prob. 76EPCh. 1 - Prob. 77EPCh. 1 - Prob. 78PCh. 1 - Prob. 79PCh. 1 - Prob. 80PCh. 1 - Prob. 81PCh. 1 - Prob. 82PCh. 1 - Using the conversion factors between W and Btu/h,...Ch. 1 - The outer surface of a spacecraft in space has an...Ch. 1 - Consider a person whose expose surface are is 1.7...Ch. 1 - Prob. 86PCh. 1 - Two surfaces, one highly polished and the other...Ch. 1 - A spherical interplanetary probe with a diameter...Ch. 1 - Prob. 89PCh. 1 - Can all three modes of heat transfer occur...Ch. 1 - Can a medium involve (a) conduction and...Ch. 1 - The deep human body temperature of a healthy...Ch. 1 - We often turn the fan on in summer to help us...Ch. 1 - Prob. 94PCh. 1 - Prob. 95PCh. 1 - Prob. 96PCh. 1 - An electronic package with a surface area of 1 m2...Ch. 1 - Consider steady heat transfer between two large...Ch. 1 - Prob. 99PCh. 1 - Prob. 100PCh. 1 - A 2-in-diameter spherical ball whose surface is...Ch. 1 - Prob. 102PCh. 1 - A 3-m-internal-diameter spherical tank made of...Ch. 1 - Prob. 104PCh. 1 - Solar radiation is incident on a 5-m2 solar...Ch. 1 - Prob. 106PCh. 1 - Prob. 107PCh. 1 - Prob. 108PCh. 1 - Prob. 109EPCh. 1 - An AISI 304 stainless steel sheet is going through...Ch. 1 - Prob. 111PCh. 1 - Prob. 112CPCh. 1 - Prob. 113PCh. 1 - Prob. 114PCh. 1 - Prob. 115PCh. 1 - Prob. 116PCh. 1 - Prob. 117PCh. 1 - Why is the metabolic rate of women, in general,...Ch. 1 - What is asymmetric thermal radiation How does it...Ch. 1 - How do (a) draft and (b) cold floor surfaces cause...Ch. 1 - Prob. 121CPCh. 1 - Why is it necessary to ventilate buildings? What...Ch. 1 - Consider a house in Atlanta, Georgia, that is...Ch. 1 - Prob. 124PCh. 1 - Prob. 125PCh. 1 - Prob. 126PCh. 1 - A 4m5m6m and room is to be heated by one ton (1000...Ch. 1 - Engine valves (cp=440J/kg.Kandp=7840kg/m3) are to...Ch. 1 - Prob. 129PCh. 1 - Prob. 130PCh. 1 - A 0.3 -cm-thick, 12-cm-high, and 18-cm-long...Ch. 1 - A 40-cm-long, 800-W electric resistance heating...Ch. 1 - It is well known that wind makes the cold air feel...Ch. 1 - An engine block with a surface area measured to be...Ch. 1 - Prob. 135PCh. 1 - Prob. 136PCh. 1 - Prob. 137PCh. 1 - Consider a person standing in a room maintained at...Ch. 1 - Prob. 139PCh. 1 - Prob. 140PCh. 1 - Prob. 141PCh. 1 - Prob. 142PCh. 1 - Prob. 143PCh. 1 - Prob. 144PCh. 1 - Prob. 145PCh. 1 - Prob. 146PCh. 1 - A 2-kW electric resistance heater submerged in...Ch. 1 - Prob. 148PCh. 1 - A cold bottled drink (m=2.5kg,cp=4200J/kg.K) at...Ch. 1 - Prob. 150PCh. 1 - Air enters a 12-m-long, 7-cm-diameter pipe at 50oC...Ch. 1 - Prob. 152PCh. 1 - Steady heat conduction occurs through a...Ch. 1 - Heat is lost through a brick wall (k=0.72W/m.K),...Ch. 1 - Prob. 155PCh. 1 - A 40-cm-long, 0.4-cm-diameter electric resistance...Ch. 1 - Prob. 157PCh. 1 - Over 90 percent of the energy dissipated by an...Ch. 1 - On a still, cleat night, the sky appears to be a...Ch. 1 - Prob. 160PCh. 1 - Prob. 161PCh. 1 - A persons head can be approximated as a...Ch. 1 - A person standing in a room loses heat to the air...Ch. 1 - Prob. 164PCh. 1 - Write an essay on how microwave ovens work, and...Ch. 1 - Using information form the utility bill for the...Ch. 1 - It is well know that at the same outdoor air...
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- 1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.arrow_forward2.55 A long, 1-cm-diameter electric copper cable is embedded in the center of a 25-cm-square concrete block. If the outside temperature of the concrete is 25oC and the rate of electrical energy dissipation in the cable is 150 W per meter length, determine temperatures at the outer surface and at the center of the cable.arrow_forward2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.arrow_forward
- 1.76 Explain a fundamental characteristic that differentiates conduction from convection and radiation.arrow_forward3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer coefficient on one side is and on the other side is . If the temperature of both streams is suddenly changed from 38°C to 93°C, determine how long it takes for the copper plate to reach a temperature of 82°C.arrow_forwardA cooling system is to be designed for a food storage warehouse for keeping perishable foods cool prior to transportation to grocery stores. The warehouse has an effective surface area of 1860 m2 exposed to an ambient air temperature of 32C. The warehouse wall insulation (k=0.17W/(mK)) is 7.5 cm thick. Determine the rate at which heat must be removed (W) from the warehouse to maintain the food at 4C.arrow_forward
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- Show that the rate of heat conduction per unit length through a long, hollow cylinder of inner radius ri and outer radius ro, made of a material whose thermal conductivity varies linearly with temperature, is given by qkL=TiTo(rori)/kmA where Ti = temperature at the inner surface To = temperature at the outer surface A=2(rori)/ln(ro/ri)km=ko[1+k(Ti+To)/2]L=lenthofcyclinderarrow_forward2.9 In a large chemical factory, hot gases at 2273 K are cooled by a liquid at 373 K with gas-side and liquid-side convection heat transfer coefficients of 50 and , respectively. The wall that separates the gas and liquid streams is composed of a 2-cm thick oxide layer on the gas side and a 4-cm thick slab of stainless steel on the liquid side. There is a contact resistance between the oxide layer and the steel of . Determine the rate of heat loss from hot gases through the composite wall to the liquid.arrow_forward1.2 The weight of the insulation in a spacecraft may be more important than the space required. Show analytically that the lightest insulation for a plane wall with a specified thermal resistance is the insulation that has the smallest product of density times thermal conductivity.arrow_forward
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