For what value of Prandtl number, St = f/2 ?
For what value of Prandtl number, St = f/2 ?
A. 1.5
B. 1
C. > 1
D. < 1
Chemical Heat Transfer
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In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid___________________?
In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid___________________?A. Varies directly as the area and the LMTD
B. Directly proportional to LMTD and inversely proportional to the area
C. Varies as square of the area
D. None of these -
Grashoff number is given by________________?
Grashoff number is given by________________?A. gD3.β.Δtρ2/μ2
B. gD2βΔtρ/μ2
C. gD2βΔtP2μ
D. gD3βΔtP2/μ -
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law?
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law?A. Parabolic
B. Hyperbolic
C. Linear
D. Logarithmic -
Which of the following is the most widely used heat insulating material for pipelines carrying steam ?
Which of the following is the most widely used heat insulating material for pipelines carrying steam ?A. Tar dolomite bricks followed by asbestos
B. Fireclay refractory followed by aluminium sheet
C. Cotton followed by aluminium foil
D. 85% magnesia cement and glass wool -
Evaporator tubes are generally_____________________?
Evaporator tubes are generally_____________________?A. Horizontal
B. Vertical
C. Inclined
D. Random -
In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is _____________ the outlet temperature of the cold fluid?
In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is _____________ the outlet temperature of the cold fluid?A. Equal to
B. More than
C. Less than
D. Either more or less than (depending upon the fluid) -
Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?
Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?A. Grashoff
B. Reynolds
C. Both ‘a’ & ‘b’
D. Prandtl & Grashoff -
Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the_________________?
Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the_________________?A. Existence of thermal boundary layer
B. Temperature gradient produced due to density difference
C. Buoyancy of the bubbles produced at active nucleation site
D. None of these -
Reason for operating an evaporator in multiple effects is to secure ___________________?
Reason for operating an evaporator in multiple effects is to secure ___________________?A. Increased steam economy
B. Decreased steam consumption
C. Both A. and B.
D. Increased capacity