Q. A 10 cm diameter 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

View solution

Q. Fouling factor

View solution

Q. In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient

View solution

Q. The steam ejector is used to

View solution

Q. For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area

View solution

Q. The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are

View solution

Q. Crystal size in a continuous crystalliser depends upon the

View solution

Q. Heat waves

View solution

Q. Air is best heated with steam in a heat exchanger of

View solution

Q. Which of the following is generally considered as opaque surface towards radiations?

View solution

Q. Black liquor generated during paper manufacture is concentrated in a

View solution

Q. When vaporisation takes place directly at the heating surface, it is called

View solution

Q. Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively)

View solution

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

View solution

Q. Fourier's law applies to the heat transfer by

View solution

Q. The equivalent diameter for pressure drop is __________ that for heat transfer.

View solution

Q. Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer.

View solution

Q. The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K= 0.04 W/m.°K and thickness 0.16m is 10 W/m². The temperature of the inside wall is - 5°C. The outside wall temperature is

View solution

Q. Thermal conductivity of a conducting solid material depends upon its

View solution

Q. Pick out the wrong statement.

View solution