In an experiment, the temperature of a hot gas stream is to be measured by a thermocouple with a spherical junction. Due to the nature of this experiment, the response time of the thermocouple to register 99 percent of the initial temperature difference must be within 5 s. The properties of the thermocouple junction are k = 35 W/m·K, r = 8500 kg/m3, and cp = 320 J/kg·K. If the heat transfer coefficient between the thermocouple junction and the gas is 250 W/m2·K, determine the diameter of the junction.

In an experiment, the temperature of a hot gas stream is to be measured by a thermocouple with a spherical junction. Due to the nature of this experiment, the response time of the thermocouple to register 99 percent of the initial temperature difference must be within 5 s. The properties of the thermocouple junction are k = 35 W/m·K, r = 8500 kg/m3, and cp = 320 J/kg·K. If the heat transfer coefficient between the thermocouple junction and the gas is 250 W/m2·K, determine the diameter of the junction.

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter19: Temperature, Thermal Expansion And Gas Laws

Section: Chapter Questions

Problem 61PQ

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