menu
bartleby
search
close search
Hit Return to see all results

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
2-1. 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
help_outline

Image Transcriptionclose

2-1. 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
check_circleAnswer
Step 1

Time can be calculated by,

Energy 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 = .
help_outline

Image Transcriptionclose

Energy 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...

lold xtole
new
new
85.25.556
11.36
tpe = 41.67sec
new
help_outline

Image Transcriptionclose

lold xtole new new 85.25.556 11.36 tpe = 41.67sec new

fullscreen

Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Our solutions are written by experts, many with advanced degrees, and available 24/7

See Solution
Tagged in

Engineering

Mechanical Engineering

Related Mechanical Engineering Q&A

Find answers to questions asked by student like you

Show more Q&A add
question_answer

Q: The 32-kg spool of outer radius ro 420 mm has a centroidal radius of gyration k 265 mm and a central...

A: Draw the free body diagram of the spool as:

question_answer

Q: Inlet stagnation air pressure of a two-dimensional compressor cascade is 1.0 bar and inlet stagnatio...

A: Inlet stagnation air pressure = 1.0 barInlet stagnation temperature = 295 KInlet Mach Number = 0.75I...

question_answer

Q: The collar of mass m is released from rest while in position A and subsequently travels with negligi...

A: Thank you for your question, there are four subparts given in the question and it is not mentioned w...

question_answer

Q: 3. Water flowing through a pipe assumes a laminar-flow velocity profile at some section is parabolic...

A: Consider the given water flow through the pipe

question_answer

Q: The flexible band F is attached at E to the rotating sector and leads over the guide pulley G. Deter...

A: Given data:The velocity of band vb=3.8m/sThe free body diagram of the mechanism with the instantaneo...

question_answer

Q: Compute the planar density value for (1,-1,1) plane of BCC iron (Fe). Zfe=26Rfe=0.126nmAfe=55.845g/m...

A: Planar density for a certain plane in a unit cell is expressed as:

question_answer

Q: True or False: There is only one model space allowed in a drawing file.

A: In AutoCAD, the model space is the drawing environment and is used to create and visualize the 3D mo...

question_answer

Q: A steam turbine at steady state is operated at part load by throttling the steam to a lower pressure...

A: Frist we have to draw the line diagram by using assumptions given in the problem 

question_answer

Q: 13.1-4. Temperature Distribution in a Hollow Sphere. Derive Eq. (13.1-18) for the steady- state cond...

A: Consider a hollow sphere of constant density and thermal conductivity.Let the outer surface is at te...

Sorry about that. What wasn’t helpful?