2 A wire of diameter D = 2 mm and uniform temperature T has an electrical resistance of 0.01 2/m and a current flow of 20 A. (a) What is the rate at which heat is dissipated per unit length of wire? What is the heat dissipation per unit volume within the wire? (b) If the wire is not insulated and is in ambient air and large surroundings for which T = Tsur = 20°C, what is the temperature T of the wire? The wire has an emissivity of 0.3, and the coefficient associated with heat transfer by natural convection may be approximated by an expression of the form, h = C[(TT)/D]4, where C = 1.25 W/m7/4. K5/4 If the wire is coated with plastic insulation of 2-mm thickness and a thermal conductivity of 0.25 W/m K, what are the inner and outer surface temperatures of the insulation? The insulation has an emissivity of 0.9, and the convection coefficient is given by the expression of part (b). Explore the effect of the insu- lation thickness on the surface temperatures.
2 A wire of diameter D = 2 mm and uniform temperature T has an electrical resistance of 0.01 2/m and a current flow of 20 A. (a) What is the rate at which heat is dissipated per unit length of wire? What is the heat dissipation per unit volume within the wire? (b) If the wire is not insulated and is in ambient air and large surroundings for which T = Tsur = 20°C, what is the temperature T of the wire? The wire has an emissivity of 0.3, and the coefficient associated with heat transfer by natural convection may be approximated by an expression of the form, h = C[(TT)/D]4, where C = 1.25 W/m7/4. K5/4 If the wire is coated with plastic insulation of 2-mm thickness and a thermal conductivity of 0.25 W/m K, what are the inner and outer surface temperatures of the insulation? The insulation has an emissivity of 0.9, and the convection coefficient is given by the expression of part (b). Explore the effect of the insu- lation thickness on the surface temperatures.
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
![2
A wire of diameter D = 2 mm and uniform temperature
T has an electrical resistance of 0.01 N/m and a current
flow of 20 A.
(a) What is the rate at which heat is dissipated per unit
length of wire? What is the heat dissipation per
unit volume within the wire?
(b) If the wire is not insulated and is in ambient air
and large surroundings for which T = Tsur = 20°C,
what is the temperature T of the wire? The
wire has an emissivity of 0.3, and the coefficient
associated with heat transfer by natural convection
may be approximated by an expression of the
form, h = C[(T-T)/D]¹/4, where C = 1.25
W/m7/4.K5/4
(c)
If the wire is coated with plastic insulation of 2-mm
thickness and a thermal conductivity of 0.25 W/m.K,
what are the inner and outer surface temperatures of
the insulation? The insulation has an emissivity of
0.9, and the convection coefficient is given by the
expression of part (b). Explore the effect of the insu-
lation thickness on the surface temperatures.
Note:
1. The metal wire itself is assumed to be at a single
temperature.
2. This is in a cylindrical coordinate.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fbe157a84-8ac6-419a-bfda-98f3e9e167bf%2Fcf887c44-e533-48a8-b79f-fd9249548d5d%2Facrcri3l_processed.jpeg&w=3840&q=75)
Transcribed Image Text:2
A wire of diameter D = 2 mm and uniform temperature
T has an electrical resistance of 0.01 N/m and a current
flow of 20 A.
(a) What is the rate at which heat is dissipated per unit
length of wire? What is the heat dissipation per
unit volume within the wire?
(b) If the wire is not insulated and is in ambient air
and large surroundings for which T = Tsur = 20°C,
what is the temperature T of the wire? The
wire has an emissivity of 0.3, and the coefficient
associated with heat transfer by natural convection
may be approximated by an expression of the
form, h = C[(T-T)/D]¹/4, where C = 1.25
W/m7/4.K5/4
(c)
If the wire is coated with plastic insulation of 2-mm
thickness and a thermal conductivity of 0.25 W/m.K,
what are the inner and outer surface temperatures of
the insulation? The insulation has an emissivity of
0.9, and the convection coefficient is given by the
expression of part (b). Explore the effect of the insu-
lation thickness on the surface temperatures.
Note:
1. The metal wire itself is assumed to be at a single
temperature.
2. This is in a cylindrical coordinate.
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 3 steps with 9 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