1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
bearhunter [10]
3 years ago
13

A composite wall is composed of 20 cm of concrete block with k = 0.5 W/m-K and 5 cm of foam insulation with k = 0.03 W/m-K. The

temperature of on the foam side is 25oC while the temperature on the block side is 0oC. What is the temperature at the interface between the block and the foam?
Engineering
1 answer:
wariber [46]3 years ago
3 0

Answer:

4.8°C

Explanation:

The rate of heat transfer through the wall is given by:

q=\frac{Ak}{L}dT

\frac{q}{A}=\frac{k}{L}dT

Assumptions:

1) the system is at equilibrium

2) the heat transfer from foam side to interface and interface to block side is equal. There is no heat retention at any point

3) the external surface of the wall (concrete block side) is large enough that all heat is dissipated and there is no increase in temperature of the air on that side

{k_{fi}= 0.03 W/m.K

{L_{fi}= 5 cm = 0.05 m

{T_{fi}= 25 \°C

{k_{cb} = 0.5 W/m.K

{L_{cb}= 20 cm = 0.20 m

{T_{cb}= 0 \°C

{T_{m}= ? \°C = temperature at the interface

Solving for {T_{m} will give the temperature at the interface:

\frac{q}{A}=\frac{k_{fi} }{L_{fi} }(T_{fi} -T_{m})=\frac{k_{cb} }{L_{cb} }(T_{m} -T_{cb})

\frac{0.03}{0.05 }(25 -T_{m})=\frac{0.5}{0.2}(T_{m} -0})

15 -0.6T_{m}=2.5T_{m}

3.1T_{m}=15

T_{m}=4.8

You might be interested in
50 points
Burka [1]

Answer:

Water vapor

Explanation:

When water is in a vapor it tends to rise to a higher point. Because of this it would be able to reach the top of a building.

4 0
3 years ago
malott, m. e. (2003). paradox of organizational change: engineering organizations with behavioral systems analysis.
mylen [45]

Answer:

Paradox of Organizational Change: Engineering Organizations with Behavioral Systems Analysis. by. Maria E. Malott.

7 0
1 year ago
How much horse power does a Lamborghini have
statuscvo [17]
The Lamborghini SCV12 has 830 horse power.
4 0
2 years ago
Read 2 more answers
Refrigerant-134a at 400 psia has a specific volume of 0.1144 ft3/lbm. Determine the temperature of the refrigerant based on (a)
vekshin1

Answer:

a) Using Ideal gas Equation, T = 434.98°R = 435°R

b) Using Van Der Waal's Equation, T = 637.32°R = 637°R

c) T obtained from the refrigerant tables at P = 400 psia and v = 0.1144 ft³/lbm is T = 559.67°R = 560°R

Explanation:

a) Ideal gas Equation

PV = mRT

T = PV/mR

P = pressure = 400 psia

V/m = specific volume = 0.1144 ft³/lbm

R = gas constant = 0.1052 psia.ft³/lbm.°R

T = 400 × 0.1144/0.1052 = 434.98 °R

b) Van Der Waal's Equation

T = (1/R) (P + (a/v²)) (v - b)

a = Van Der Waal's constant = (27R²(T꜀ᵣ)²)/(64P꜀ᵣ)

R = 0.1052 psia.ft³/lbm.°R

T꜀ᵣ = critical temperature for refrigerant-134a (from the refrigerant tables) = 673.6°R

P꜀ᵣ = critical pressure for refrigerant-134a (from the refrigerant tables) = 588.7 psia

a = (27 × 0.1052² × 673.6²)/(64 × 588.7)

a = 3.596 ft⁶.psia/lbm²

b = (RT꜀ᵣ)/8P꜀ᵣ

b = (0.1052 × 673.6)/(8 × 588.7) = 0.01504 ft³/lbm

T = (1/0.1052) (400 + (3.596/0.1144²) (0.1144 - 0.01504) = 637.32°R

c) The temperature for the refrigerant-134a as obtained from the refrigerant tables at P = 400 psia and v = 0.1144 ft³/lbm is

T = 100°F = 559.67°R

7 0
3 years ago
Omg help mr idk what to say ahhh​
kap26 [50]

Explanation:

ответ на фото !!!!!!

7 0
3 years ago
Read 2 more answers
Other questions:
  • To ensure safe footing on penetrable surfaces,use?
    5·1 answer
  • function summedValue = SummationWithLoop(userNum) % Summation of all values from 1 to userNum summedValue = 0; i = 1; % Write a
    11·1 answer
  • How an AK 47 gun was works​
    14·1 answer
  • 10. To cut 1/4" (6 mm) thick mild steel at a rate of 40 inches per minute, the current would be set to
    7·1 answer
  • This app, I'm done, bye... I can't, bye
    11·1 answer
  • Select the answer that shows how the recognition of depreciation expense
    10·1 answer
  • A 50-mm cube of the graphite fiber reinforced polymer matrix composite material is subjected to 125-kN uniformly distributed com
    14·1 answer
  • Explain the LWD process why is it important in drilling operations?
    6·1 answer
  • 10 properties of metals?<br> ​
    10·2 answers
  • Can you help me with this task/homework.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!