An experiment was conducted to determine surface convective heat transfer coefficient for peas being frozen in an air-blast freezer. For this purpose, a metal analog of peas was used. The analog was a solid copper ball with a diameter of 1 cm. A small hole was drilled to the center of the copper ball, and a thermocouple junction was located at the center using a high-conductivity epoxy. The density of copper is 8954 kg/m³, and its specific heat is 3830 J/(kg K). The copper ball (at a uniform initial temperature of 10 ºC) was hung in the path of air flow (at -40 °C) and the center temperature indicated by the thermocouple was recorded. The following table lists the temperature at 1-min intervals for 14 min. Determine the surface heat transfer coefficient from these data.

An experiment was conducted to determine surface convective heat transfer coefficient for peas being frozen in an air-blast freezer. For this purpose, a metal analog of peas was used. The analog was a solid copper ball with a diameter of 1 cm. A small hole was drilled to the center of the copper ball, and a thermocouple junction was located at the center using a high-conductivity epoxy. The density of copper is 8954 kg/m³, and its specific heat is 3830 J/(kg K). The copper ball (at a uniform initial temperature of 10 ºC) was hung in the path of air flow (at -40 °C) and the center temperature indicated by the thermocouple was recorded. The following table lists the temperature at 1-min intervals for 14 min. Determine the surface heat transfer coefficient from these data.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Concept explainers

Strengthening of Alloys

Strengthening of the alloys is required as metals become weak due to various lattice defects, metal bonding phenomena. The strength of the metals is not enough for any mechanical work. The internal dislocations of any metals arise due to forming processes. Due to the movement of these dislocations, the metals are plastically deformed.

Question

An experiment was conducted to determine surface convective heat transfer coefficient for peas being
frozen in an air-blast freezer. For this purpose, a metal analog of peas was used. The analog was a solid
copper ball with a diameter of 1 cm. A small hole was drilled to the center of the copper ball, and a
thermocouple junction was located at the center using a high-conductivity epoxy. The density of
copper is 8954 kg/m³, and its specific heat is 3830 J/(kg K). The copper ball (at a uniform initial
temperature of 10 °C) was hung in the path of air flow (at -40 °C) and the center temperature indicated
by the thermocouple was recorded. The following table lists the temperature at 1-min intervals for 14
min. Determine the surface heat transfer coefficient from these data.
Time (s)
0
60
120
180
240
300
360
420
480
540
600
660
720
780
840
Temp (°C)
10
9
8
7
6
5
4
3,5
2,5
1
1
0
-2
-2
-3

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