  2-1. Temperature Response in Cooling a Wire. A small copper wire with a diameter of0.792 mm and initially at 366.5 K is suddenly immersed in a liquid held constant at311 K. The convection coefficient h 85.2 W/m K. The physical properties can beassumed constant and are k =374 W/m K, c, = 0.389 kJ/kg K, and p = 8890 kg/m2.(a) Determine the time in seconds for the average temperature of the wire todrop to 338.8 K (one-half the initial temperature difference).(b) Do the same but for h 11.36 W/m2 K(c) For part (b), calculate the total amount of heat removed for a wire 1.0 mрu (Along.(a) t 5.66 sAns.the Smou hire is lonsasbumeNhere rraolius, here radliusyinder hitu xChapter 14Principles of Unsteady-State Heat Transfer

Question help_outlineImage Transcriptionclose2-1. Temperature Response in Cooling a Wire. A small copper wire with a diameter of 0.792 mm and initially at 366.5 K is suddenly immersed in a liquid held constant at 311 K. The convection coefficient h 85.2 W/m K. The physical properties can be assumed constant and are k =374 W/m K, c, = 0.389 kJ/kg K, and p = 8890 kg/m2. (a) Determine the time in seconds for the average temperature of the wire to drop to 338.8 K (one-half the initial temperature difference). (b) Do the same but for h 11.36 W/m2 K (c) For part (b), calculate the total amount of heat removed for a wire 1.0 m р u (A long. (a) t 5.66 s Ans. the Smou hire is lons asbume Nhere rraolius , here radlius yinder hitu x Chapter 14 Principles of Unsteady-State Heat Transfer fullscreen
Step 1

Time can be calculated by, help_outlineImage TranscriptioncloseEnergy balance equation dT -- hА (Т —Т,) dt — тс рrLC, " -hx2mrL(T-T,) dt рar'LC, hx(2лrL); Т -Т,. 7 dT dt prC Т -т. - In Т, —Т. t =- 0 prC Т-Т, - In 4/h Т, — Т, ...() t = . fullscreen
Step 2

On substituting the values,

The value of time is 5.556sec.

Step 3

(b).

tnew is given b... help_outlineImage Transcriptioncloselold xtole new new 85.25.556 11.36 tpe = 41.67sec new fullscreen

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