Explanation Given Information: The temperature of the hot water is 80 ° C , the average velocity of the water is 1.5 m / s , the length of the pipe is 25 m , the outer diameter of the pipe is 5 cm , the length of the pipe in the ambient air is 2 m , the vertical grounded length of the pipe is 3 m , the horizontal grounded length of the pipe is 20 m , the temperature of the ambient air is 8 ° C , the thermal conductivity of the ground is 1.5 W / m ⋅ K , the convective heat transfer coefficient between surface of the pipe and the ambient air is 22 W / m 2 ⋅ K and the surface temperature of the ground is 0 ° C . Divide the pipe in three sections. Consider the section of the pipe in the ambient air as the section (1), the vertically grounded pipe section as section (2) and horizontal grounded pipe section as the section (3). Write the expression for the thermal resistance offered due to convection in the ambient air. R = 1 h A s R = 1 h π D L 1 ....... (I) Here, the convective heat transfer coefficient is h and the surface area of the pipe in the ambient air is A s , the diameter of the pipe is D and the length of the pipe in section (1) is L 1 . Write the expression for the rate of heat transfer from the section (1) of the pipe. Q ˙ 1 = T − T ∞ R ....... (II) Here the temperature of the hot water is T and the temperature of the ambient air is T ∞ . Write the expression for the surface factor of the section (2). S 2 = 2 π L 2 ln ( 4 L 2 D ) ....... (III) Here, the length of the pipe of the section (2) is L 2 . Write the expression for the rate of heat transfer in the section (2). Q ˙ 2 = S 2 k ( T − T s ) ....... (IV) Write the expression for the shape factor of the pipe of section (3). S 3 = 2 π L 3 ln ( 8 z π D ) ....... (V) Here, the length of the pipe in section (3) is L 3 and the depth of the pipe from the surface is z . Write the expression for the rate of heat transfer from the section (3) of the pipe. Q ˙ 3 = S 3 k ( T − T s ) ....... (VI) Write the expression for the total heat transfer from the pipe. Q ˙ = Q ˙ 1 + Q ˙ 2 + Q ˙ 3 ....... (VII) Calculation: Substitute 22 W / m 2 ⋅ K for h , 5 cm for D , 2 m for L 1 in the Equation (I). R = 1 ( 22 W / m 2 ⋅ K ) π ( 5 cm ) ( 2 m ) = 1 ( 22 W / m 2 ⋅ K ) π ( 5 cm ) ( 10 − 2 m 1 cm ) ( 2 m ) = 0.145 K / W Substitute 0.145 K / W for R , 80 ° C for T and 8 ° C for T ∞ in the Equation (II). Q ˙ 1 = 80 ° C − 8 ° C 0.145 K / W = ( 80 ° C + 273 ) K − ( 8 ° C + 273 ) K 0.145 K / W = 496.55 W Substitute 3 m for L 2 and 5 cm for D in the Equation (III). S 2 = 2 π ( 3 m ) ln ( 4 ( 3 m ) ( 5 cm ) ) = 6 π m ln ( 4 ( 3 m ) ( 5 cm ) ( 10 − 2 m 1 cm ) ) = 3 To determine (b) The temperature drop of hot water along the length of the pipe.

5th Edition

ISBN: 9781307573060

Author: CENGEL

Publisher: MCG/CREATE

See similar textbooks

Question

Chapter 3, Problem 147P

To determine

(a)

The total rate of heat loss from the hot water.

To determine

(b)

The temperature drop of hot water along the length of the pipe.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Chapter 3, Problem 146EP

Chapter 3, Problem 148P

Chapter 3 Solutions

HEAT+MASS TRANSFER-SI ED. EBOOK >I<

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. 16P Ch. 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. 22P Ch. 3 - A1.0m1.5m double-pane window consists of two...Ch. 3 - Prob. 24P Ch. 3 - Prob. 25P Ch. 3 - Prob. 26P Ch. 3 - Prob. 27P Ch. 3 - Prob. 28EP Ch. 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. 32P Ch. 3 - Prob. 33P Ch. 3 - Prob. 34P Ch. 3 - Prob. 35P Ch. 3 - Prob. 36P Ch. 3 - Heat is to be conducted along a circuit board that...Ch. 3 - Prob. 38EP Ch. 3 - Consider a house that has a 10m20-m base and a...Ch. 3 - Prob. 40EP Ch. 3 - Prob. 41P Ch. 3 - Prob. 42P Ch. 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. 47CP Ch. 3 - Consider two surfaces pressed against each other....Ch. 3 - Prob. 49P Ch. 3 - Two 5-cm-diameter, 15-cm-long aluminum bars...Ch. 3 - Prob. 51P Ch. 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. 55P Ch. 3 - Prob. 56P Ch. 3 - Prob. 57P Ch. 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. 62EP Ch. 3 - Prob. 63P Ch. 3 - Prob. 64P Ch. 3 - Prob. 65P Ch. 3 - Prob. 66P Ch. 3 - Prob. 67P Ch. 3 - Prob. 68P Ch. 3 - A 12-m-long and 5-m-high wall is constructed of...Ch. 3 - Prob. 70EP Ch. 3 - Prob. 71P Ch. 3 - Prob. 72P Ch. 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. 76P Ch. 3 - Prob. 77P Ch. 3 - Prob. 78P Ch. 3 - Superheated steam at an average temperature 20C is...Ch. 3 - Prob. 80EP Ch. 3 - Prob. 81EP Ch. 3 - Prob. 82P Ch. 3 - Prob. 83P Ch. 3 - Prob. 84P Ch. 3 - Prob. 85P Ch. 3 - Prob. 86EP Ch. 3 - Prob. 87P Ch. 3 - Prob. 88P Ch. 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. 93P Ch. 3 - Prob. 94P Ch. 3 - Prob. 95P Ch. 3 - What is the critical radius of insulation? How is...Ch. 3 - Prob. 97CP Ch. 3 - Prob. 98CP Ch. 3 - Prob. 99CP Ch. 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. 103P Ch. 3 - Prob. 104P Ch. 3 - Hot air is to be cooled as it is forced to flow...Ch. 3 - Prob. 106CP Ch. 3 - Prob. 107CP Ch. 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. 119P Ch. 3 - Consider a very long rectangular fin attached to a...Ch. 3 - Prob. 121P Ch. 3 - Prob. 122EP Ch. 3 - Prob. 123EP Ch. 3 - Prob. 124P Ch. 3 - Prob. 125P Ch. 3 - Prob. 126P Ch. 3 - Prob. 127P Ch. 3 - Prob. 128P Ch. 3 - Prob. 129P Ch. 3 - Prob. 130P Ch. 3 - Prob. 131P Ch. 3 - Prob. 132P Ch. 3 - Prob. 133P Ch. 3 - Prob. 134P Ch. 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. 138P Ch. 3 - What is a conduction shape factor? How is it...Ch. 3 - What is the value of conduction shape factors in...Ch. 3 - Prob. 141P Ch. 3 - A thin-walled cylindrical container is placed...Ch. 3 - Prob. 143P Ch. 3 - Prob. 144P Ch. 3 - Prob. 145P Ch. 3 - Prob. 146EP Ch. 3 - Prob. 147P Ch. 3 - Prob. 148P Ch. 3 - Prob. 149P Ch. 3 - Prob. 150P Ch. 3 - Prob. 151P Ch. 3 - Prob. 152P Ch. 3 - Consider a house with a flat roof whose outer...Ch. 3 - Prob. 154P Ch. 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. 158CP Ch. 3 - What is a radiant barrier? What kinds of materials...Ch. 3 - Consider a house whose attic space is ventilated...Ch. 3 - Prob. 161P Ch. 3 - Prob. 162P Ch. 3 - Prob. 163P Ch. 3 - Prob. 164P Ch. 3 - Prob. 165P Ch. 3 - Prob. 166P Ch. 3 - Determine the winter R-value and the U-factor of a...Ch. 3 - The overall heat transfer coefficient (the...Ch. 3 - Prob. 169EP Ch. 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. 173P Ch. 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. 177P Ch. 3 - Prob. 178P Ch. 3 - Prob. 179P Ch. 3 - Prob. 180P Ch. 3 - Prob. 181P Ch. 3 - Prob. 182P Ch. 3 - Prob. 183P Ch. 3 - Prob. 184P Ch. 3 - Prob. 185P Ch. 3 - A total of 10 rectangular aluminum fins...Ch. 3 - Prob. 187P Ch. 3 - A plane wall surface at 200C is to be cooled with...Ch. 3 - Prob. 189P Ch. 3 - Prob. 190P Ch. 3 - Prob. 191P Ch. 3 - Prob. 192P Ch. 3 - A 0.6-rn-diameter, 1.9-rn-long cylindrical tank...Ch. 3 - Prob. 194P Ch. 3 - Prob. 195P Ch. 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. 198P Ch. 3 - Heat is generated steadily in a 3-cm-diameter...Ch. 3 - Prob. 200P Ch. 3 - Prob. 201P Ch. 3 - Prob. 202P Ch. 3 - Prob. 203P Ch. 3 - Prob. 204P Ch. 3 - Consider two walls. A and B, with the same surface...Ch. 3 - Prob. 206P Ch. 3 - A room at 20C air temperature is losing heat to...Ch. 3 - Prob. 208P Ch. 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. 216P Ch. 3 - The walls of a food storage facility are made of a...Ch. 3 - The equivalent thermal resistance for the thermal...Ch. 3 - Prob. 219P Ch. 3 - Prob. 220P Ch. 3 - Prob. 221P Ch. 3 - The fin efficiency is defined as the ratio of the...Ch. 3 - Prob. 223P Ch. 3 - In the United States, building insulation is...Ch. 3 - Prob. 225P Ch. 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. 231P Ch. 3 - A house with 200-m2 floor space is to be heated...

Knowledge Booster

Recommended textbooks for you

Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY