10B.8. Electrical heating of a pipe (Fig. 10B.8). In the manufacture of glass-coated steel pipes, it is common practice first to heat the pipe to the melting range of glass and then to contact the hot pipe surface with glass granules. These granules melt and wet the pipe surface to form a tightly adhering nonporous coat. In one method of preheating the pipe, an electric current is passed along the pipe, with the result that the pipe is heated (as in §10.2). For the purpose of this problem make the following assumptions: (i) The electrical conductivity of the pipe k, is constant over the temperature range of in- terest. The local rate of electrical heat production S, is then uniform throughout the pipe wall. (ii) The top and bottom of the pipe are capped in such a way that heat losses through them are negligible. (iii) Heat loss from the outer surface of the pipe to the surroundings is given by New- ton's law of cooling:q,h(T,T). Here h is a suitable heat transfer coefficient. How much electrical power is needed to maintain the inner pipe surface at some desired temperature, T., for known k, T., h, and pipe dimensions? Answer: P Power supply Ambient air temperature T Pipe wall Fig. 10B.8. Electrical heating of a pipe. TR(1 KLT, T₁) (1-k²)R (KR)² 2h R³ [(1-1)-2 Ink] 4k
10B.8. Electrical heating of a pipe (Fig. 10B.8). In the manufacture of glass-coated steel pipes, it is common practice first to heat the pipe to the melting range of glass and then to contact the hot pipe surface with glass granules. These granules melt and wet the pipe surface to form a tightly adhering nonporous coat. In one method of preheating the pipe, an electric current is passed along the pipe, with the result that the pipe is heated (as in §10.2). For the purpose of this problem make the following assumptions: (i) The electrical conductivity of the pipe k, is constant over the temperature range of in- terest. The local rate of electrical heat production S, is then uniform throughout the pipe wall. (ii) The top and bottom of the pipe are capped in such a way that heat losses through them are negligible. (iii) Heat loss from the outer surface of the pipe to the surroundings is given by New- ton's law of cooling:q,h(T,T). Here h is a suitable heat transfer coefficient. How much electrical power is needed to maintain the inner pipe surface at some desired temperature, T., for known k, T., h, and pipe dimensions? Answer: P Power supply Ambient air temperature T Pipe wall Fig. 10B.8. Electrical heating of a pipe. TR(1 KLT, T₁) (1-k²)R (KR)² 2h R³ [(1-1)-2 Ink] 4k
Introduction to Chemical Engineering Thermodynamics
8th Edition
ISBN:9781259696527
Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Chapter1: Introduction
Section: Chapter Questions
Problem 1.1P
Related questions
Question
![10B.8. Electrical heating of a pipe (Fig. 10B.8). In the manufacture of glass-coated steel pipes, it is
common practice first to heat the pipe to the melting range of glass and then to contact the hot
pipe surface with glass granules. These granules melt and wet the pipe surface to form a
tightly adhering nonporous coat. In one method of preheating the pipe, an electric current is
passed along the pipe, with the result that the pipe is heated (as in §10.2). For the purpose of
this problem make the following assumptions:
(i) The electrical conductivity of the pipe k, is constant over the temperature range of in-
terest. The local rate of electrical heat production S, is then uniform throughout the pipe wall.
(ii) The top and bottom of the pipe are capped in such a way that heat losses through
them are negligible.
(iii) Heat loss from the outer surface of the pipe to the surroundings is given by New-
ton's law of cooling:q,h(T,T). Here h is a suitable heat transfer coefficient.
How much electrical power is needed to maintain the inner pipe surface at some desired
temperature, T., for known k, T., h, and pipe dimensions?
Answer: P
Power
supply
Ambient air
temperature T
Pipe wall
Fig. 10B.8. Electrical heating of a pipe.
TR(1 KLT, T₁)
(1-k²)R (KR)²
2h
R³ [(1-1)-2 Ink]
4k](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fe5592b58-ab16-4eb0-bdd2-73a8d4634b11%2F795f748c-8ec9-4336-b215-44f8f45ec136%2F070kst_processed.jpeg&w=3840&q=75)
Transcribed Image Text:10B.8. Electrical heating of a pipe (Fig. 10B.8). In the manufacture of glass-coated steel pipes, it is
common practice first to heat the pipe to the melting range of glass and then to contact the hot
pipe surface with glass granules. These granules melt and wet the pipe surface to form a
tightly adhering nonporous coat. In one method of preheating the pipe, an electric current is
passed along the pipe, with the result that the pipe is heated (as in §10.2). For the purpose of
this problem make the following assumptions:
(i) The electrical conductivity of the pipe k, is constant over the temperature range of in-
terest. The local rate of electrical heat production S, is then uniform throughout the pipe wall.
(ii) The top and bottom of the pipe are capped in such a way that heat losses through
them are negligible.
(iii) Heat loss from the outer surface of the pipe to the surroundings is given by New-
ton's law of cooling:q,h(T,T). Here h is a suitable heat transfer coefficient.
How much electrical power is needed to maintain the inner pipe surface at some desired
temperature, T., for known k, T., h, and pipe dimensions?
Answer: P
Power
supply
Ambient air
temperature T
Pipe wall
Fig. 10B.8. Electrical heating of a pipe.
TR(1 KLT, T₁)
(1-k²)R (KR)²
2h
R³ [(1-1)-2 Ink]
4k
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution!
Trending now
This is a popular solution!
Step by step
Solved in 1 steps with 2 images
Recommended textbooks for you
Introduction to Chemical Engineering Thermodynami…
Chemical Engineering
ISBN:
9781259696527
Author:
J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:
McGraw-Hill Education
Elementary Principles of Chemical Processes, Bind…
Chemical Engineering
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY
Elements of Chemical Reaction Engineering (5th Ed…
Chemical Engineering
ISBN:
9780133887518
Author:
H. Scott Fogler
Publisher:
Prentice Hall
Introduction to Chemical Engineering Thermodynami…
Chemical Engineering
ISBN:
9781259696527
Author:
J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:
McGraw-Hill Education
Elementary Principles of Chemical Processes, Bind…
Chemical Engineering
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY
Elements of Chemical Reaction Engineering (5th Ed…
Chemical Engineering
ISBN:
9780133887518
Author:
H. Scott Fogler
Publisher:
Prentice Hall
Industrial Plastics: Theory and Applications
Chemical Engineering
ISBN:
9781285061238
Author:
Lokensgard, Erik
Publisher:
Delmar Cengage Learning
Unit Operations of Chemical Engineering
Chemical Engineering
ISBN:
9780072848236
Author:
Warren McCabe, Julian C. Smith, Peter Harriott
Publisher:
McGraw-Hill Companies, The