Taking the convection heat transfer coefficient on both sides of the plate to be 860 W/m2 ·K, deter- mine the temperature of the sheet metal when it leaves the oil bath. Also, determine the required rate of heat removal from the oil to keep its temperature constant at 45°C.
Answers
Answer:
Hello your question is incomplete attached below is the complete question
answer :
a) 95.80°C
b) 8.23 MW
Explanation:
Convection heat transfer coefficient = 860 W/m^2 . k
a) Calculate for the temp of sheet metal when it leaves the oil bath
first step : find the Biot number
Bi = hLc / K ------- ( 1 )
where : h = 860 W/m^2 , Lc = 0.0025 m , K = 60.5 W/m°C
Input values into equation 1 above
Bi = 0.036 which is < 1 ( hence lumped parameter analysis can be applied )
next : find the time constant
t ( time constant ) = h / P*Cp *Lc --------- ( 2 )
where : p = 7854 kg/m^3 , Lc = 0.0025 m , h = 860 W/m^2, Cp = 434 J/kg°C
Input values into equation 2 above
t ( time constant ) = 0.10092 s^-1
Determine the elapsed time
T = L / V = 9/20 = 0.45 min
∴ temp of sheet metal when it leaves the oil bath
= (T(t) - 45 ) / (820 - 45) = e^-(0.10092 * 27 )
T∞ = 45°C
Ti = 820°C
hence : T(t) = 95.80°C
b) Calculate the required rate of heat removal form the oil
Q = mCp ( Ti - T(t) ) ------------ ( 3 )
m = ( 7854 *2 * 0.005 * 20 ) = 26.173 kg/s
Cp = 434 J/kg°C
Ti = 820°C
T(t) = 95.80°C
Input values into equation 3 above
Q = 8.23 MW
Related Questions
A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 5 in.2 and that approximately 2.3 kg had corroded away during the submersion. Assuming a corrosion penetration rate of 200 mpy for this alloy in seawater, estimate the time of submersion in years. The density of steel is 7.9 g/cm3.
Answers
Answer:
the estimated time of submersion is 17.7 years
Explanation:
Given the data in the question;
estimate the time of submersion in years.
we write down the relation between time of submersion and corrosion penetration as follows;
CPR(mpy) = K × W(mg) / [ A(in²) × p(g/cm³) × t(hr) ]
we solve for t
t = (K × W) / ( AP × CPR )
given that;
Area A = 5 in²
W = 2.3 kg = 2.3 × 10⁶ mg
density of steel p = 7.9 g/cm³
CPR = 200
we know that K is 534
so we substitute
t = (534 × 2.3 × 10⁶ mg) / ( 5 in² × 7.9 g/cm³ × 200 mpy )
t = 1,228,200,000 / 7900
t = 155468.3544 hr
t = 155468.3544 hr × ( 1 yrs / ( 365 × 24 hrs )
t = 17.7 years
Therefore, the estimated time of submersion is 17.7 years
4. Oil system cleaning products should not use solvents because:
A) O Solvents smell bad
B) Solvents are completely removed during the service
CO Solvents have no impact on dirt and debris
DO Solvents can damage certain plastics and rubbers found in the engine
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Answer:
Solvents can damage certain plastics and rubbers found in the engine
Explanation: