DESIGN AND CONSTRUCTION OF AN INDUCTION FURNACE COOLING SYSTEM

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DESIGN AND CONSTRUCTION OF AN INDUCTION
FURNACE(COOLING SYSTEM)
Presented by MG THANT ZIN WIN Roll No Ph.D-M-7
Supervisors Dr Mi Sanda Mon
Daw Khin War Oo
22nd Seminar
22.12.2004
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Review on Previous Seminar

• Three types of cooling system
• Cooling pond system
• Spray pond system
• Cooling tower system
• The following known data need to be determine
  the required size of a cooling pond.
• Relative humidity
• Wind velocity
• Dry-bulb air temperature
• Solar heat gain
• Water quantity
• Water inlet and outlet temperature

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Solar Constant
The solar constant (Isc) is the energy from the
sun per unit time, received on a unit area of
surface, perpendicular to the direction of
propagation of the radiation, and at the earths
mean distance from the sun, outside the earths
atmosphere.
Fig The sun-earth geometry
The values of solar constant are 1353
W/m2 or 1.940 cal/cm2 min 1165 kcal/h m2 or 4871
kJ/m2 h or 428 BTU/h ft2
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Direct, Diffuse, and Total Solar Radiation

• Beam radiation
• Solar radiation intercepted by a surface with
  negligible direction change
• and scattering in the atmosphere.
• Diffuse radiation
• The solar radiation scattered by aerosols, dust
  and by Rayleigh mechanism. It does not have a
  unique direction.
• Total radiation
• It is also called global radiation and the sum
  of diffuse and beam radiation.

Fig Direct, diffuse, and total solar radiation
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Solar Radiation Geometry
Basic EarthSun Angles The position of a point
P on the earths surface with respect to the
suns rays is represented by the latitude, hour
angle for the point, and the suns declination.
Latitude
hour angle
suns declination
Fig Latitude, hour angle, and suns declination
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Declination
The declination is the angle made by the line
joining the centers of the sun and the earth with
its projection of the equatorial plane.
where, n the day of the year
The declination angle varies from a maximum
value of 23.45 on June 21 to a minimum value
of 23.45 on Dec. 21.
Fig Variation of declination over the year
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Sunrise, Sunset and Day Length
The hour angle corresponding to sunrise or
sunset on a horizontal surface can be found from
the equation.
15 Degrees of the hour angle is equivalent to 1
hour.
The corresponding day length (in hour), denoted
by is given by
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Empirical Equation for Predicting the Monthly
Average Global Solar Radiation
The following relation is the generally accepted
modified form of the Angstrom-type regression
equation, relating the monthly average daily
global radiation to the average daily sunshine
hours.
monthly average of the daily global radiation
on a horizontal surface at a location
(kJ/m2 day)
monthly average of the daily global radiation
on a horizontal surface at the same location on a
clear day (kJ/m2 day)
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monthly average of the sunshine hours per day
at the location
monthly average of the maximum possible
sunshine hours (or day length) per day at the
location
a, b regression constants obtained by data
fitting
Calculation of has been simplified by the
following equation.
n the Julian day number
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For example Estimate the average daily global
radiation on a horizontal surface at Bangalore
(77 40' E, 12 59' N) during the month of March,
if the average sunshine hours per day are 9.5.
At Bangalore a 0.18 and b 0.64. We shall
assume for the calculation of on March
16, n 75.
Using Coopers equation and substituting the
desire values,
The sunrise hour angle,
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Day length,
Angstrom equation,
The average daily global radiation on horizontal
surface,
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Five Models for Regression Constant a and b
Turtons model
Rietvelds model
Fagbenles model
Freres model
McCullochs model
Rietvelds model is selected for our calculation
of the monthly average daily global radiation
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THANK YOU