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Question: water is to be boiled at an elevation of 1500...

Question details

      Water is to be boiled at an elevation of 1500 m where the atmospheric pressure is 84.53 kPa. The boiling is carried out in stainless steel pan with a 30 cm diameter. The pan is placed on top of a 3-kW electric burner. If 60% of the heat generated by the burner is transferred to the water during boiling determine the temperature of the inner surface of the bottom of the pan.                                   (Ans: 101.6oC)

Additional data and information:

Forster-Zuber correlation:

 

Where:

hNB = nucleate boiling heat transfer coefficient (W m−2 K−1).

kL = thermal conductivity of the liquid (W m−1 K−1).

Cp,L = specific heat capacity of the liquid (J kg−1 K−1).

ρL = density of liquid (kg m−3).

σ = surface tension (N m−1).

µL = viscosity of the liquid (N s m−2).

ΔHvap = enthalpy of vaporization (J kg−1).

ρv = density of vapour (kg m−3).

ΔTe = excess temperature (K).

Ps = vapour pressure of liquid at surface temperature Ts (Pa).

Psat = saturation vapour pressure of liquid (Pa).

The following data are for water at 84.53 kPa and 95°C:

kL =  0.678 W m−1 K−1

Cp,L = 4212 J kg−1 K−1

ρL = 961.5 kg m−3

σ = 0.0599 N m−1

µL = 0.297x10−3 N s m−2

ΔHvap = 2270x103 J kg−1

ρv = 0.50 kg m−3

Ps = 101x103 Pa

Psat = 84.53x103 Pa

 

HEAT AND MASS QUES , PLS HELP ME TO SOLVE QUES ABOVE

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