Unformatted text preview: measurement in a gas stream. The convection coefficient between the junction surface and the gas is h= 400 W/m 2 .K, and the junction thermophysical properties are k= 20 W/m.K, c p = 400 J/kg.K, and = 8500kg/m 3 . Determine the junction diameter needed for the thermocouple to have a time constant of 2 second. If the junction is at 35 o C and is placed in a gas stream that is at 250 o C, how long will it take for the junction to reach 220 o C? Hint: The time constant (or thermal time constant) is defined as a product of resistance and capacitance (as done in class) L t x...
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This note was uploaded on 01/10/2012 for the course CHE 303 taught by Professor Kim during the Fall '09 term at Drexel.
- Fall '09