Question

Q. Unsteady conduction

A large steel plate 0.02 m thick leaves a heat treating furnace at 425 oC. And the plate is

plunged into water (at 25 oC) and cooled from both sides. How long does it take for the

maximum temperature to reach 65 oC?

For steel plate: thermal conductivity, k=30 W/m·K, density ?=7600 kg/m3, heat capacity

cp=700 J/kg·K. Heat transfer coefficients: h=6000 W/m2·K in water.

Please use two methods to calculate this question:

(1) Directly apply the exact analytical solution (one term approximation, verify whether this

approximation is valid) given in Lecture note. You need use Appendix to find the values

for different functions.

(2) Use the diagram below to solve the problem. Water temperature is T1. Initial temperature

is T0. Center of the plate at y=0, surface of the plate at y=L.

Compare your results obtained from different methods, which one is more accurate?

Answer #1

consider a 0.8 cm thick steel plate with a thermal
conductivity of 50W/m-k.When the inside surface of the plate is
subjected to a uniform heat flux 0f 5*104 w/m2 the oter surface
temperature of the plate is measured to be 110c under steady
operating condition
a)express the differential equation and the boundary
conditions for steady one dimensional heat conduction through the
wall
b)obtain the relation for the variation of temperature
in the plate by solving the differential equation.
c)evaluate the...

71 mm thick horizontal plate made of an opaque material of
thermal conductivity k= 25 W/m-K. At the bottom, water flows at a
temperature of T∞,w = 25C, whereas air flows at the top of the
plate at T∞,a = 710 C having convection coefficient of ha= 71
W/m2-K. Assuming a diffused top of the plate that receives an
irradiated flux of 7100W/m2, of which 30% is reflected back. The
top and bottom surface temperatures are maintained at 43 C...

Homework-9
Due:
Q) A fuel plate is fabricated from 0.3 cm thick 1.5% enriched
uranium. The cladding is 0.25 mm 304 stainless steel. The coolant
saturation temperature is 260 oC. The
average thermal neutron flux is 2.5 X
1014
neutrons/cm2 /s. The surface
temperature of the clad is 350 oC.
Assume any missing data to answer the following questions:.
1) Write an expression of the heat generated per unit volume
2 What is the heat flux at the surface of...

4-23 After heat treatment, the 2-cm thick metal
plates (k = 180 W/m·K, ρ = 2800 kg/m3, and cp
= 880 J/kg·K) are conveyed through a cooling chamber with a
length of 10 m. The plates enter the cooling
chamber at an initial temperature of 500°C. The cooling chamber
maintains a temperature of 10°C, and
the convection heat transfer coefficient is given as a function
of the air velocity blowing over the plates h
= 33V0.8, where h is in...

After heat treatment, the 2-cm thick metal plates (k = 180
W/m·K, ρ = 2800 kg/m3, and cp = 880 J/kg·K) are conveyed through a
cooling chamber with a length of 10 m. The plates enter the cooling
chamber at an initial temperature of 500°C. The cooling chamber
maintains a temperature of 10°C, and the convection heat transfer
coefficient is given as a function of the air velocity blowing over
the plates h = 33V0.8, where h is in W/m2·K...

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