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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Chapter 3, Problem 221P
To determine
To find:Insulation exterior surface temperature.
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A 5.1-m internal diameter spherical tank made of 1.6-cm-thick stainless steel (k = 15 w/m- c) is used to store iced water at 0 C. the wall of the room are also at 31 C. The convection heat transfer coefficient at the inner and the outer surface of the tank are 80 w/m - c, respectively. Determine (a) the rate of heat transfer of the iced water and (b) the amount of iced at 0 C that melts during a 24 h period. the heat of fusion of water at atmospheric pressure is 333.7 kj/kg.
Consider a heat treatment furnace situated in a 30oC room with an average convection heat transfer coefficient of 12W/m2K. The door of the furnace is made of 20 mm-thick steel plate with thermal conductivity, k=25W/mK. A constant heat flux of 8kW/m2 is applied to the inner surface of the door, and the outer surface has an emissivity of 0.23. What is the outer surface temperature of the furnace door? Is this safe? What can you do to make it safe?
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Maps
Electrically heated draw batch furnaces are commonly
used in the heat treatment industry. Consider a draw batch
furnace front made of a 20-mm thick steel plate with a ther-
mal conductivity of 25 W/m-K. The furnace is situated in a
room with surrounding air temperature of 20°C and an aver-
age convection heat transfer coefficient of 10 W/m2-K. If the
inside surface of the furnace front is subjected to uniform
heat flux of 5 kW/m² and the outer surface has an emissiv-
ity of 0.30, determine the inside surface temperature of the
furnace front.
= 20°C
Furnace
fron
4, = 5 kW/m
Air, 20 C
h= 10 W/m K
e = 0.30
kn25 W/m-K
Chapter 3 Solutions
Heat and Mass Transfer: Fundamentals and Applications
Ch. 3 - Consider heat conduction through a wall of...Ch. 3 - Consider heat conduction through a plane wall....Ch. 3 - What does the thermal resistance of a medium...Ch. 3 - Can we defme the convection resistance for a unit...Ch. 3 - Consider steady heat transfer through the wall of...Ch. 3 - How is the combined heat transfer coefficient...Ch. 3 - Why are the convection and the radiation...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Someone comments that a microwave oven can be...Ch. 3 - Consider two cold canned drinks, one wrapped in a...
Ch. 3 - The bottom of a pan is made of a 4-mm-thick...Ch. 3 - Consider a surface of area A at which the...Ch. 3 - How does the thermal resistance network associated...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Consider a window glass consisting of two...Ch. 3 - Prob. 16PCh. 3 - Consider a person standing in a room at 20C with...Ch. 3 - Consider an electrically heated brick house...Ch. 3 - A12-cm18-cm circuit board houses on its surface...Ch. 3 - Water is boiling in a 25-cm-diameter aluminum pan...Ch. 3 - A cylindrical resistor element on a circuit board...Ch. 3 - Prob. 22PCh. 3 - A1.0m1.5m double-pane window consists of two...Ch. 3 - Prob. 24PCh. 3 - Prob. 25PCh. 3 - Prob. 26PCh. 3 - Prob. 27PCh. 3 - Prob. 28EPCh. 3 - To defog the rear window of an automobile, a very...Ch. 3 - A transparent film is to be bonded onto the top...Ch. 3 - To defrost ice accumulated on the outer surface of...Ch. 3 - Prob. 32PCh. 3 - Prob. 33PCh. 3 - Prob. 34PCh. 3 - Prob. 35PCh. 3 - Prob. 36PCh. 3 - Heat is to be conducted along a circuit board that...Ch. 3 - Prob. 38EPCh. 3 - Consider a house that has a 10m20-m base and a...Ch. 3 - Prob. 40EPCh. 3 - Prob. 41PCh. 3 - Prob. 42PCh. 3 - What is thermal contact resistance? How is it...Ch. 3 - Will the thermal contact resistance be greater for...Ch. 3 - Explain how the thermal contact resistance can be...Ch. 3 - A waII consists of two layers of insulation...Ch. 3 - Prob. 47CPCh. 3 - Consider two surfaces pressed against each other....Ch. 3 - Prob. 49PCh. 3 - Two 5-cm-diameter, 15-cm-long aluminum bars...Ch. 3 - Prob. 51PCh. 3 - Two identical aluminum plates with thickness of 30...Ch. 3 - A tvolayer wall is made of two metal plates, with...Ch. 3 - An aluminum plate and a stainless steel plate are...Ch. 3 - Prob. 55PCh. 3 - Prob. 56PCh. 3 - Prob. 57PCh. 3 - What are the two approaches used in the...Ch. 3 - The thermal resistance networks can also be used...Ch. 3 - When plotting the thermal resistance network...Ch. 3 - A 10-cm-thick vall is to be constructed with...Ch. 3 - Prob. 62EPCh. 3 - Prob. 63PCh. 3 - Prob. 64PCh. 3 - Prob. 65PCh. 3 - Prob. 66PCh. 3 - Prob. 67PCh. 3 - Prob. 68PCh. 3 - A 12-m-long and 5-m-high wall is constructed of...Ch. 3 - Prob. 70EPCh. 3 - Prob. 71PCh. 3 - Prob. 72PCh. 3 - What is an infinitely long cylinder? When is it...Ch. 3 - Can the thermal resistance concept be used for a...Ch. 3 - Consider a short cylinder whose top and bottom...Ch. 3 - Prob. 76PCh. 3 - Prob. 77PCh. 3 - Prob. 78PCh. 3 - Superheated steam at an average temperature 20C is...Ch. 3 - Prob. 80EPCh. 3 - Prob. 81EPCh. 3 - Prob. 82PCh. 3 - Prob. 83PCh. 3 - Prob. 84PCh. 3 - Prob. 85PCh. 3 - Prob. 86EPCh. 3 - Prob. 87PCh. 3 - Prob. 88PCh. 3 - Liquid hydrogen is flowing through an insulated...Ch. 3 - Exposure to high concentrations of gaseous ammonia...Ch. 3 - A mixture of chemicals is flowing in a pipe...Ch. 3 - Ice slurry is being transported in a pipe...Ch. 3 - Prob. 93PCh. 3 - Prob. 94PCh. 3 - Prob. 95PCh. 3 - What is the critical radius of insulation? How is...Ch. 3 - Prob. 97CPCh. 3 - Prob. 98CPCh. 3 - Prob. 99CPCh. 3 - A pipe is insulated such that the outer radius of...Ch. 3 - A 0.083-in-diameter electrical wire at 90F is...Ch. 3 - Repeat Prob. 3-109E, assuming a thermal contact...Ch. 3 - Prob. 103PCh. 3 - Prob. 104PCh. 3 - Hot air is to be cooled as it is forced to flow...Ch. 3 - Prob. 106CPCh. 3 - Prob. 107CPCh. 3 - The fins attached to a surface are determined to...Ch. 3 - Explain how the fins enhance heat transfer from a...Ch. 3 - How does the overall effectiveness of a finned...Ch. 3 - Hot water is to be cooled as it flows through the...Ch. 3 - Consider two finned surfaces that are identical...Ch. 3 - The heat transfer surface area of a fin is equal...Ch. 3 - Does the (a) efficiency and (b) effectiveness of a...Ch. 3 - Two pin fins are identical, except that the...Ch. 3 - Two plate fins of constant rectangular cross...Ch. 3 - Two finned surfaces are identical, except that the...Ch. 3 - Obtain a relation for the fin efficiency for a fin...Ch. 3 - Prob. 119PCh. 3 - Consider a very long rectangular fin attached to a...Ch. 3 - Prob. 121PCh. 3 - Prob. 122EPCh. 3 - Prob. 123EPCh. 3 - Prob. 124PCh. 3 - Prob. 125PCh. 3 - Prob. 126PCh. 3 - Prob. 127PCh. 3 - Prob. 128PCh. 3 - Prob. 129PCh. 3 - Prob. 130PCh. 3 - Prob. 131PCh. 3 - Prob. 132PCh. 3 - Prob. 133PCh. 3 - Prob. 134PCh. 3 - The human body is adaptable to extreme climatic...Ch. 3 - Consider the conditions of Example 3-14 in the...Ch. 3 - Consider the conditions of Example 3-14 in the...Ch. 3 - Prob. 138PCh. 3 - What is a conduction shape factor? How is it...Ch. 3 - What is the value of conduction shape factors in...Ch. 3 - Prob. 141PCh. 3 - A thin-walled cylindrical container is placed...Ch. 3 - Prob. 143PCh. 3 - Prob. 144PCh. 3 - Prob. 145PCh. 3 - Prob. 146EPCh. 3 - Prob. 147PCh. 3 - Prob. 148PCh. 3 - Prob. 149PCh. 3 - Prob. 150PCh. 3 - Prob. 151PCh. 3 - Prob. 152PCh. 3 - Consider a house with a flat roof whose outer...Ch. 3 - Prob. 154PCh. 3 - Radioactive material, stored in a spherical vessel...Ch. 3 - What is the R-value of a wall? How does it differ...Ch. 3 - What is effective emissivity for a plane-parallel...Ch. 3 - Prob. 158CPCh. 3 - What is a radiant barrier? What kinds of materials...Ch. 3 - Consider a house whose attic space is ventilated...Ch. 3 - Prob. 161PCh. 3 - Prob. 162PCh. 3 - Prob. 163PCh. 3 - Prob. 164PCh. 3 - Prob. 165PCh. 3 - Prob. 166PCh. 3 - Determine the winter R-value and the U-factor of a...Ch. 3 - The overall heat transfer coefficient (the...Ch. 3 - Prob. 169EPCh. 3 - Determine the summer and winter R-values. in m2 ....Ch. 3 - The overall heat transfer coefficient of a wall is...Ch. 3 - Two homes are identical, except that the walls of...Ch. 3 - Prob. 173PCh. 3 - Consider two identical people each generating 60 V...Ch. 3 - Cold conditioned air at 12C is flowing inside a...Ch. 3 - Hot water is flowing at an average velocity of 1.5...Ch. 3 - Prob. 177PCh. 3 - Prob. 178PCh. 3 - Prob. 179PCh. 3 - Prob. 180PCh. 3 - Prob. 181PCh. 3 - Prob. 182PCh. 3 - Prob. 183PCh. 3 - Prob. 184PCh. 3 - Prob. 185PCh. 3 - A total of 10 rectangular aluminum fins...Ch. 3 - Prob. 187PCh. 3 - A plane wall surface at 200C is to be cooled with...Ch. 3 - Prob. 189PCh. 3 - Prob. 190PCh. 3 - Prob. 191PCh. 3 - Prob. 192PCh. 3 - A 0.6-rn-diameter, 1.9-rn-long cylindrical tank...Ch. 3 - Prob. 194PCh. 3 - Prob. 195PCh. 3 - A thin-walled spherical tank is buried in the...Ch. 3 - Heat is lost at a rate of 275 W per m2 area of a 1...Ch. 3 - Prob. 198PCh. 3 - Heat is generated steadily in a 3-cm-diameter...Ch. 3 - Prob. 200PCh. 3 - Prob. 201PCh. 3 - Prob. 202PCh. 3 - Prob. 203PCh. 3 - Prob. 204PCh. 3 - Consider two walls. A and B, with the same surface...Ch. 3 - Prob. 206PCh. 3 - A room at 20C air temperature is losing heat to...Ch. 3 - Prob. 208PCh. 3 - A 1-cm-diameter, 30cm-long fin made of aluminum...Ch. 3 - A hot surface at 80C in air at 20C is to be cooled...Ch. 3 - A cylindrical pin fin of diameter 0.6 cm and...Ch. 3 - A 3-cm-long. 2-nuti x 2-mm rectangular...Ch. 3 - Two finned surfaces with long fins are identical,...Ch. 3 - A 20-cm-diameter hot sphere at 120C is buried in...Ch. 3 - A 25-cm-diameter, 2.4-rn-long vertical cylinder...Ch. 3 - Prob. 216PCh. 3 - The walls of a food storage facility are made of a...Ch. 3 - The equivalent thermal resistance for the thermal...Ch. 3 - Prob. 219PCh. 3 - Prob. 220PCh. 3 - Prob. 221PCh. 3 - The fin efficiency is defined as the ratio of the...Ch. 3 - Prob. 223PCh. 3 - In the United States, building insulation is...Ch. 3 - Prob. 225PCh. 3 - A plane brick wall (k=0.7W/m.K) and is 10 cm...Ch. 3 - The temperature in deep space is close to absolute...Ch. 3 - In the design of electronic components, it is...Ch. 3 - Using cylindrical samples of the same material,...Ch. 3 - Find out about the wall construction of the cabins...Ch. 3 - Prob. 231PCh. 3 - A house with 200-m2 floor space is to be heated...
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- A 50-meter-long cast iron pipe with a 10-centimeter outside diameter goes through a 288 K temperature open environment. The temperature of the pipe's outer surface is 423 K, and the combined heat transfer coefficient on the pipe's outside surface is 25 W/m2 K. Considering and stating the necessary assumptions determine,(a) The rate of heat loss from the pipe (b) The energy lost per year if the cost of the fuel is 0.52 $/therm ( 1 therm = 105,500 kJ) c) The thickness of the insulation if 98% of the energy loss is planned to be saved. Consider the conduction coefficient of the insulation is 0.035 W/mK.arrow_forwardOil whose temperature is 30°C is flowed through a pipe with a diameter of 50 cm. The pipe is in an environment where the temperature is 20°C. So that not a lot of heat comes out of the pipe, the pipe is wrapped with an insulating material (k = 0.007 W/mK) as thick as 5 cm. If the convection coefficient of the outer surface of the pipe is 12 W/m²K, calculate the heat flow from the pipe per meter of length.arrow_forwardThe inside surface of an insulation layer is maintained at 350oC and the outside surface dissipatesheat by convection and radiation to air and wall, respectively. The temperatures of air and wall are 15 oC.The insulation layer has a thickness of 10 cm and a thermal conductivity of 15 W/m.K. What is the value ofthe heat transfer coefficient at the outside surface of the layer, if the temperature at the outside surfaceshould not exceed 225 oC? (The emissivity and the width of the surface are 0.3 and 1 m., respectively.=5.67x10-8 W/m2K4).arrow_forward
- Required Information The upper surface of a 85-cm-thick solid plate (k= 237 W/m-K) is being cooled by water with temperature of 20°C. The upper and lower surfaces ofthe solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given ask= 237 W/m K. f2 (T,1+T) = (60°C + 20°C)/2 = 40°C is kuid = 0.631 The thermal conductivity of water at the film temperature of T; W/m/K. Determine the water convection heat transfer coefficient. The water convection heat transfer coefficient is W/m2 -K.arrow_forwardA spherical tank with internal diameter of 2 m made of 2.0-cm-thick stainless steel (k=15 W/m.K) is used for storing a fluid at a temperature of 1 °C. The tank is covered with a 4-cm-thick layer of an insulation (k=0.25 W/m.K). The surrounding air is at 15 °C. The inside and outside heat transfer coefficients are 35 and 10 W/m2.K, respectively. Required: Draw the thermal resistance network (thermal circuit) and label the associated resistance and determine the following: The individual thermal resistance associated with the thermal circuit. a) b) c) d) The total thermal resistance value The rate of heat transfer The temperature difference across the tank shell and the insulation layer.arrow_forwardA 0.3-cm-thick, 12-cm-high, and 18-cm-long circuit board houses 80 closely spaced logic chips on one side, each dissipating 004 W, as shown in the figure. The board is impregnated with copper fillings and has an effective thermal cònductivity of 30 W/m-K. All the heat generated in the chips is conducted.across the circuit board and is dissipated from the back side of the board to a medium at 78°C, with a heat transfer coefficient of 40 W/m2-K. Regory RAhumimn Rcanv 71. WWw.Taz Determine the temperature T2- The temperature T2 is °C.arrow_forward
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