8. This question deals with steady-state radiation heat transfer between a sphere (r= 30 cm) and a circular disk (n=120 cm), which are separated by a center-to-center distance h= 60 cm. When the normal to the center of the disk passes through the center of the sphere, the radiation view factor is given by -0.5 2 F12=0.5 712 = 0.5 { 1 - [1 + ( ;)]"} h Surface temperatures of the sphere and the disk are 600° C and 200° C, respectively; and their emissivities are 0.9 and 0.5, respectively. a) Calculate the view factors F12 and F₂1. b) Calculate the net rate of radiation heat exchange between the sphere and the disk. c) For the given radii and temperatures of the sphere and the disk, the following four possible modifications could increase the net rate of radiation heat exchange: paint each of the two surfaces to alter their emissivities, adjust the distance between them, and provide an (refractory) enclosure. Calculate the net rate of radiation heat exchange between the two bodies if the best values are selected for each of the above modifications. T1 CS Scanned with Scanner 2 h
8. This question deals with steady-state radiation heat transfer between a sphere (r= 30 cm) and a circular disk (n=120 cm), which are separated by a center-to-center distance h= 60 cm. When the normal to the center of the disk passes through the center of the sphere, the radiation view factor is given by -0.5 2 F12=0.5 712 = 0.5 { 1 - [1 + ( ;)]"} h Surface temperatures of the sphere and the disk are 600° C and 200° C, respectively; and their emissivities are 0.9 and 0.5, respectively. a) Calculate the view factors F12 and F₂1. b) Calculate the net rate of radiation heat exchange between the sphere and the disk. c) For the given radii and temperatures of the sphere and the disk, the following four possible modifications could increase the net rate of radiation heat exchange: paint each of the two surfaces to alter their emissivities, adjust the distance between them, and provide an (refractory) enclosure. Calculate the net rate of radiation heat exchange between the two bodies if the best values are selected for each of the above modifications. T1 CS Scanned with Scanner 2 h
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
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![8. This question deals with steady-state radiation heat transfer between a sphere (r= 30 cm) and a circular disk
(n = 120 cm), which are separated by a center-to-center distance h=60 cm. When the normal to the center of
the disk passes through the center of the sphere, the radiation view factor is given by
27-0.5
Fiz=0.5 {1- [1 + (2) ] })
Surface temperatures of the sphere and the disk are 600° C and 200° C, respectively; and their emissivities are
0.9 and 0.5, respectively.
a) Calculate the view factors F12 and F21.
b)
Calculate the net rate of radiation heat exchange between the sphere and the disk.
c) For the given radii and temperatures of the sphere and the disk, the following four possible
modifications could increase the net rate of radiation heat exchange: paint each of the two surfaces to
alter their emissivities, adjust the distance between them, and provide an (refractory) enclosure.
Calculate the net rate of radiation heat exchange between the two bodies if the best values are selected
for each of the above modifications.
T1
CS Scanned with Scanner 12](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdd1585f7-e8c3-448e-85a6-28a8faf15ecb%2Fc4b10370-63ce-427b-afac-6daf8f38325c%2F03pinv_processed.jpeg&w=3840&q=75)
Transcribed Image Text:8. This question deals with steady-state radiation heat transfer between a sphere (r= 30 cm) and a circular disk
(n = 120 cm), which are separated by a center-to-center distance h=60 cm. When the normal to the center of
the disk passes through the center of the sphere, the radiation view factor is given by
27-0.5
Fiz=0.5 {1- [1 + (2) ] })
Surface temperatures of the sphere and the disk are 600° C and 200° C, respectively; and their emissivities are
0.9 and 0.5, respectively.
a) Calculate the view factors F12 and F21.
b)
Calculate the net rate of radiation heat exchange between the sphere and the disk.
c) For the given radii and temperatures of the sphere and the disk, the following four possible
modifications could increase the net rate of radiation heat exchange: paint each of the two surfaces to
alter their emissivities, adjust the distance between them, and provide an (refractory) enclosure.
Calculate the net rate of radiation heat exchange between the two bodies if the best values are selected
for each of the above modifications.
T1
CS Scanned with Scanner 12
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