21051. At constant temperature, the thermal conductivities of gases __________ with rise in pressure.
21052. Reason for operating an evaporator in multiple effect is to secure
21053. In a cooling tower, water becomes cool by
21054. In Fourier's law, the proportionality constant is called the
21055. The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation.
21056. From which country India borrowed the scheme of Indian Federation?
21057. 'Duhring's plot' is of use in
21058. Which has the lowest Prandtl number ?
21059. International Day of the Girl Child is on:
21060. Prandtl number for most of dry gases is about
21061. Prandtl number is the reciprocal of
21062. In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining the same, the temperature of the exit liquid will be
21063. For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is
21064. Multiple effect evaporation accounts for
21065. In case of a supercooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is
21066. Maximum water velocity in tubes of a 1-2 shell and tube heat exchanger may be around __________ metres/second.
21067. In Biot number, the characteristic length used is the ratio of the __________ of the solid.
21068. Which of the following is the most widely used heat insulating material for pipelines carrying steam ?
21069. Heat transfer co-efficient equation for forced convection, Nu = 0.023 Re0.8 . Prn, is not valid, if the value of
21070. Which is the best tube arrangement (in a shell and tube heat exchanger) if the fluids are clean and non-fouling ?
21071. In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid
21072. The purpose of providing expansion bellows in the shell of tubular exchanger is to
21073. A graph between __________ is called Wilson plot.
21074. Grashhoff number is given by
21075. The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is
21076. In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is