43. Heat transfer co-efficient equation for forced convection, Nu = 0.023 R

_{e}^{0.8}. P_{r}^{n}, is not valid, if the value of44. LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counterflow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface area required is the least in the __________ flow.

46. Latent heat absorbed by 1 lb of water at 212°F, when it is changed to steam at 212°F, may be around __________ BTU.

47. Sensible heat absorbed by 1 lb of water when it is heated from 32 to 212°F may be around __________ BTU.

48. When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is

49. With increase in temperature, the thermal conductivity of non-metallic amorphous solids

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