A. Pe = Re.Pr
B. Pe = Re/Pr
C. Pe = Pr/Re
D. Pe = Nu.Re
Related Mcqs:
- The critical radius ‘r’ of insulation on a pipe is given by____________________?
A. r = 2k/h
B. r = k/h
C. r = k/2h
D. r = h/k - Heat transfer efficiency leading of energy conservation in a heat exchanger can be achieved by____________________?
A. Keeping the heat transfer surface clean
B. Enhancing the fluid pumping rate
C. Increasing the tube length
D. None of these - Grashoff number is given by________________?
A. gD3.β.Δtρ2/μ2
B. gD2βΔtρ/μ2
C. gD2βΔtP2μ
D. gD3βΔtP2/μ - The absorptivity of a grey body at a given temperature _____________ with increasing wavelength of radiation?
A. Increases
B. Decreases
C. Remain constant
D. May increase or decrease; depends on the material - 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) - Thermal diffusivity is given by__________________?
A. k/ρCp
B. ρCp/k
C. μCp/a
D. μ/hCp - Graetz number is given by__________________?
A. mCp/kL
B. kL/mCp
C. mCp/kμ
D. kμ/mCp - Steady state one dimensional heat flow by conduction as given by Fourier’s low does not assume that_______________?
A. There is no internal heat generation
B. Boundary surfaces are isothermal
C. Material is anisotropic
D. Constant temperature gradient exists - The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as______________?
A. (ΔT)1/4
B. (ΔT)1/2
C. (ΔT)5/4
D. (ΔT)3/4 - Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by h = 0.023 (K/D) (DVρ/μ)0.8 (CP.μ/k)0.4. This is valid for the value of NRe equal to_______________?
A. 4000
D. > 10000
