A. CP. μ/k
B. hD/k
C. h. CP/μ
D. CP. μ/h
Correct Answer: hD/k ✔
Last Updated: March 03, 2019
Related MCQs
- In the equation Q = UAΔt; Δt is__________?
- For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in__________?
- Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3/min) of density 800 kg/m3 and specific heat of 2 kJ/kg.K enters at 20°C. The log mean temperature difference in °C is approximately ?
- Graetz number is given by__________?
- Reynold’s analogy states that__________?
- Which of the following has the minimum thermal conductivity ?
- For an ideal black body__________?
- For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a __________ evaporator?
- Leidenfrost point is a term concerned with the__________?
- Which of the following is not used as a medium for high temperature heating ?
- The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by __________ times, when the number of tube passes is increased to 8?
- In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred__________?
- A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is__________?
- The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is__________?
- Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger ?
- What is the absorptivity of a black body?
- Economy of a multiple effect evaporator is not influenced much by the__________?
- Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube__________?
- In case of evaporators, liquid entrainment results primarily due to__________?
- Heat exchangers operating, when the asymptotic range is reached, ?
- In counter flow compared to parallel flow, ?
- Mode of heat transfer involved in the cooling of air cooled internal combustion engine is__________?
- In a single effect evaporator, the economy is__________?
- Small scale evaporation is done in a__________?
- In a liquid-liquid heat exchanger, for the same process temperature, the ratio of the LMTD in parallel flow to the LMTD in counter flow is always__________?
- Low thermal conductivity of heat insulating materials is due to its__________?
- Low thermal conductivity of heat insulating materials is due to its__________?
- In case of a vertical tube evaporator, with increase in the liquor level, the__________?
- The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the__________?
- Thermal diffusivity is given by__________?
- In a forward feed multiple effect, the pressure build up will be__________?
- Which of the following has the minimum absorptivity ?
- Convective heat transfer, in which heat is transferred by movement of warmed matter is described by__________?
- If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is__________?
- In an extended surface heat exchanger, fluid having lower co-efficient__________?
- The critical radius ‘r’ of insulation on a pipe is given by__________?
- In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of__________?
- A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________?
- Sensible heat of hot industrial flue gases cannot be recovered by a/an__________?
- In case of a vertical tube evaporator, with increase in the liquor level, the __________ is increased?
- The heat flux in the nucleate boiling regimes is proportional to (where, ΔT = excess temperature) ?
- In a multiple effect evaporator, the effect of boiling point elevation is to__________?
- Film condensation is promoted on a/an __________ surface?
- In a boiling curve, the peak heat flux is called the __________ point?
- In case of __________ boiling, the bubbles formed on a submerged hot surface get absorbed in the mass of the liquid?
- Nusselt number (for forced convection heat transfer) is a function of the __________ number?
- The separation of liquid droplets from the vapor is done by a/an __________ in the evaporators?
- For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is__________?
- In forced circulation, the heating element is injected__________?
- According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor) ?
- The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body)?