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.Management Sciences
Category: Chemical Heat Transfer
A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?
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A. Lower heat transfer area
B. Lower steam economy
C. Higher steam economy
D. Higher solute concentration in the product
Value of Prandtl number for water ranges from_________________?
A. 1 to 2
B. 5 to 10
C. 100 to 500
D. 1000 to 2000
The Fourier number (defined as a.t/L2) is used in the analysis of problem involving heat transfer by_______________?
A. Forced convection
B. Natural convection
C. Transient conduction
D. Steady state conduction
The interchange factor for radiation heat transfer from surface ‘x’ to surface ‘y’ in case of an infinite parallel planes with emissivities εx & εy is given by_______________?
A. εx + εy
B. εx . εy
C. 1/εx + 1/εy
D. (εx + εy)/( εx + εy – εx . εy)
Stefan’s block body radiation law can also be derived from ______________ law?
A. Kirchoff’s
B. Planck’s
C. Fourier’s
D. None of these
Which of the following has the minimum thermal conductivity ?
A. Nitrogen
B. Steel
C. Carbon black
D. Tar
The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is_________________?
A. Nusselt number
B. Sherwood number
C. Schmidt number
D. Stanton number
A body cools down from 75°C to 70°C in 10 minutes. It will cool down from 70° C to 65° C in ______________ minutes?
A. 10
B. > 10
C. < 10
D. Either B. or C., depends on the mass of the body
Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube___________________?
A. Exit-fluid temperature > wall temperature
B. Exit fluid temperature < wall temperature
C. Exit fluid temperature = wall temperature
D. Graetz number > 100
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