# Register now to access 7 million high quality study materials (What's Course Hero?) Course Hero is the premier provider of high quality online educational resources. With millions of study documents, online tutors, digital flashcards and free courseware, Course Hero is helping students learn more efficiently and effectively. Whether you're interested in exploring new subjects or mastering key topics for your next exam, Course Hero has the tools you need to achieve your goals.

1 Page

### sm3_3

Course: MAE Heat Trans, Spring 2010
School: Seoul National
Rating:

Word Count: 403

#### Document Preview

3.3 KNOWN: PROBLEM Desired inner surface temperature of rear window with prescribed inside and outside air conditions. FIND: (a) Heater power per unit area required to maintain the desired temperature, and (b) Compute and plot the electrical power requirement as a function of T,o for the range -30 T,o 0C with ho of 2, 20, 65 and 100 W/m2K. Comment on heater operation needs for low ho. If h ~ Vn, where V is the...

Register Now

#### Unformatted Document Excerpt

Coursehero >> Other International >> Seoul National >> MAE Heat Trans

Course Hero has millions of student submitted documents similar to the one
below including study guides, practice problems, reference materials, practice exams, textbook help and tutor support.

Course Hero has millions of student submitted documents similar to the one below including study guides, practice problems, reference materials, practice exams, textbook help and tutor support.
3.3 KNOWN: PROBLEM Desired inner surface temperature of rear window with prescribed inside and outside air conditions. FIND: (a) Heater power per unit area required to maintain the desired temperature, and (b) Compute and plot the electrical power requirement as a function of T,o for the range -30 T,o 0C with ho of 2, 20, 65 and 100 W/m2K. Comment on heater operation needs for low ho. If h ~ Vn, where V is the vehicle speed and n is a positive exponent, how does the vehicle speed affect the need for heater operation? SCHEMATIC: ASSUMPTIONS: (1) Steady-state conditions, (2) One-dimensional heat transfer, (3) Uniform heater flux, q , (4) Constant properties, (5) Negligible radiation effects, (6) Negligible film resistance. h PROPERTIES: Table A-3, Glass (300 K): k = 1.4 W/mK. ANALYSIS: (a) From an energy balance at the inner surface and the thermal circuit, it follows that for a unit surface area, T ,i Ts,i 1 hi q = h Ts,i T ,o + q = h L k + 1 ho T,i Ts,i 1 hi 2 o Ts,i T ,o L k + 1 ho 15 C 10 C = 0.004 m 1.4 W m K 2 ( o ) 2 + 1 65 W m K 25 C 15 C 1 10 W m K 2 o o q = (1370 100 ) W m = 1270 W m h < (b) The heater electrical requirement power as a function of the exterior air temperature for different exterior convection coefficients is shown in the plot. When ho = 2 W/m2K, the heater is unecessary, since the glass is maintained at 15C by the interior air. If h ~ Vn, we conclude that, with higher vehicle speeds, the exterior convection will increase, requiring increased heat power to maintain the 15C condition. 3500 3000 Heater power (W/m^2) 2500 2000 1500 1000 500 0 -30 -20 -10 0 Exterior air temperature, Tinfo (C) h = 20 W/m^2.K h = 65 W/m^2.K h = 100 W/m^2.K COMMENTS: With q = 0, the inner surface temperature with T,o = -10C would be given by h T,i Ts,i T,i T ,o = 1 hi 0.10 = = 0.846, 1 h i + L k + 1 h o 0.118 or Ts,i = 25 C 0.846 35 C = 4.6 C . o () o o Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful.
Find millions of documents on Course Hero - Study Guides, Lecture Notes, Reference Materials, Practice Exams and more. Course Hero has millions of course specific materials providing students with the best way to expand their education.

Below is a small sample set of documents:

Seoul National - MAE - Heat Trans
PROBLEM 3.4KNOWN: Curing of a transparent film by radiant heating with substrate and film surface subjected to known thermal conditions. FIND: (a) Thermal circuit for this situation, (b) Radiant heat flux, q (W/m2), to maintain bond at o as a function of
Seoul National - MAE - Heat Trans
PROBLEM 3.7 KNOWN: A layer of fatty tissue with fixed inside temperature can experience different outside convection conditions. FIND: (a) Ratio of heat loss for different convection conditions, (b) Outer surface temperature for different convection condi
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Seoul National - MAE - Heat Trans
Seoul National - MAE - Heat Trans
Seoul National - MAE - Heat Trans
Seoul National - MAE - Heat Trans
Seoul National - MAE - Heat Trans
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation o
Seoul National - MAE - Heat Trans
PROBLEM 4.1KNOWN: Method of separation of variables for two-dimensional, steady-state conduction. FIND: Show that negative or zero values of 2, the separation constant, result in solutions which cannot satisfy the boundary conditions. SCHEMATIC:ASSUMPTI
Seoul National - MAE - Heat Trans
PROBLEM 4.2KNOWN: Two-dimensional rectangular plate subjected to prescribed uniform temperature boundary conditions. FIND: Temperature at the mid-point using the exact solution considering the first five non-zero terms; assess error resulting from using
Seoul National - MAE - Heat Trans
PROBLEM 4.3KNOWN: Temperature distribution in the two-dimensional rectangular plate of Problem 4.2. FIND: Expression for the heat rate per unit thickness from the lower surface (0 x 2, 0) and result based on first five non-zero terms of the infinite seri
Seoul National - MAE - Heat Trans
PROBLEM 4.4 KNOWN: Rectangular plate subjected to prescribed boundary conditions. FIND: Steady-state temperature distribution. SCHEMATIC:ASSUMPTIONS: (1) Steady-state, 2-D conduction, (2) Constant properties. ANALYSIS: The solution follows the method of
Seoul National - MAE - Heat Trans
PROBLEM 4.5KNOWN: Boundary conditions on four sides of a rectangular plate. FIND: Temperature distribution. SCHEMATIC:yq sWT1T10 0 T1 LxASSUMPTIONS: (1) Two-dimensional, steady-state conduction, (2) Constant properties. ANALYSIS: This problem dif
Seoul National - MAE - Heat Trans
PROBLEM 4.14KNOWN: Tube embedded in the center plane of a concrete slab. FIND: The shape factor and heat transfer rate per unit length using the appropriate tabulated relation, SCHEMATIC:ASSUMPTIONS: (1) Two-dimensional conduction, (2) Steady-state cond
Seoul National - MAE - Heat Trans
PROBLEM 4.15 KNOWN: Dimensions and boundary temperatures of a steam pipe embedded in a concrete casing. FIND: Heat loss per unit length. SCHEMATIC:ASSUMPTIONS: (1) Steady-state conditions, (2) Negligible steam side convection resistance, pipe wall resist
Seoul National - MAE - Heat Trans
PROBLEM 4.16KNOWN: Thin-walled copper tube enclosed by an eccentric cylindrical shell; intervening space filled with insulation. FIND: Heat loss per unit length of tube; compare result with that of a concentric tube-shell arrangement. SCHEMATIC:ASSUMPTI
Seoul National - MAE - Heat Trans
PROBLEM 4.51KNOWN: Square shape subjected to uniform surface temperature conditions. FIND: (a) Temperature at the four specified nodes; estimate the midpoint temperature To, (b) Reducing the mesh size by a factor of 2, determine the corresponding nodal t
Seoul National - MAE - Heat Trans
PROBLEM 4.53KNOWN: Volumetric heat generation in a rectangular rod of uniform surface temperature. FIND: (a) Temperature distribution in the rod, and (b) With boundary conditions unchanged, heat generation rate causing the midpoint temperature to reach 6
Seoul National - MAE - Heat Trans
PROBLEM 5.5 KNOWN: Diameter and initial temperature of steel balls cooling in air. FIND: Time required to cool to a prescribed temperature. SCHEMATIC:ASSUMPTIONS: (1) Negligible radiation effects, (2) Constant properties. ANALYSIS: Applying Eq. 5.10 to a
Seoul National - MAE - Heat Trans
PROBLEM 5.7 KNOWN: The temperature-time history of a pure copper sphere in an air stream. FIND: The heat transfer coefficient between the sphere and the air stream. SCHEMATIC:ASSUMPTIONS: (1) Temperature of sphere is spatially uniform, (2) Negligible rad
Seoul National - MAE - Heat Trans
PROBLEM 5.8KNOWN: Solid steel sphere (AISI 1010), coated with dielectric layer of prescribed thickness and thermal conductivity. Coated sphere, initially at uniform temperature, is suddenly quenched in an oil bath. FIND: Time required for sphere to reach