Description : Corresponding to Prandtl number in heat transfer, the dimensionless group in mass transfer is the __________ number. (A) Schmidt (B) Sherwood (C) Peclet (D) Stanton
Last Answer : (A) Schmidt
Description : Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number. (A) Sherwood (B) Schmidt (C) Peclet (D) Stanton
Last Answer : (A) Sherwood
Description : In case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the __________ number. (A) Lewis (B) Grashoff (C) Sherwood
Last Answer : (A) Lewis
Description : (NRe . NSc ) is termed in mass transfer operation as the __________ number. (A) Stanton (B) Sherwood (C) Peclet (D) None of these
Last Answer : (C) Peclet
Description : NSc /NPr is called the (A) Psychrometric ratio (B) Lewis number (C) Sherwood number (D) Stanton number
Last Answer : (B) Lewis number
Description : The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is (A) Nusselt number (B) Sherwood number (C) Schmidt number (D) Stanton numbe
Last Answer : (C) Schmidt number
Description : Pick out the wrong statement. (A) Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection (B) The ratio NNu /NRe . Npr is ... convection to that by conduction (D) The Colburn jH factor for heat transfer is given by Nst Npr
Last Answer : (D) The Colburn jH factor for heat transfer is given by Nst Npr
Description : . (NSh /NRe .NSc ) is termed in mass transfer operation as the (A) Stanton number (B) Peclet number (C) Thermal diffusivity (D) Momentum diffusivity
Last Answer : (A) Stanton number
Description : Which of the following is not concerned with the heat transfer? (A) Brinkman number (B) Stanton number (C) Schmidt number (D) Peclet number
Description : Which of the following plays an important role in problems of simultaneous heat and mass transfer (A) Lewis number (B) Schmidt number (C) Prandtl number (D) Sherwood number
Last Answer : (A) Lewis number
Description : Pick out the wrong statement. (A) The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one (B) Sherwood number for flow in pipes can be expressed ... flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz
Last Answer : (C) According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2
Description : The ratio of kinematic viscosity to thermal diffusivity is called the __________ number. (A) Peclet (B) Prandtl (C) Stanton (D) Nusselt
Last Answer : (B) Prandtl
Description : Which is not concerned directly with mass transfer? (A) Schmidt number (B) Sherwood number (C) Lewis relationship (D) Froude number
Last Answer : (D) Froude number
Description : NRe . NPr ) (D/L) is called the __________ number (A) Peclet (B) Stanton (C) Graetz (D) None of these
Last Answer : (C) Graetz
Description : Pick out the wrong statement pertaining to the analogy between equations of heat and mass transfer operations. (A) Sherwood number in mass transfer is analogous to Nusselt number in heat transfer ... heat transfer (D) Reynolds number remains the same in both heat and mass transfer
Last Answer : (C) Reynolds number in mass transfer is analogous to Grashoff number in heat transfer
Description : Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to ... tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side
Last Answer : (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger
Description : Nusselt number is a function of Prandtl number and __________ number of fluid in natural convection heat transfer. (A) Grashoff (B) Biot (C) Stanton
Last Answer : (A) Grashoff
Description : Lewis number, which is important in problems involving simultaneous heat and mass transfer, is the ratio of (A) Mass diffusivity to momentum diffusivity (B) Thermal diffusivity to mass diffusivity (C) Momentum diffusivity to thermal diffusivity (D) None of these
Last Answer : (B) Thermal diffusivity to mass diffusivity
Description : For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as (A) Re 0.33 (B) Re 0.53 (C) Re 0.83 (D) Re
Last Answer : (C) Re 0.83
Description : Which of the following is directly concerned with the heat transfer? (A) Strouhal number (B) Sherwood number (C) Euler number (D) Grashoff number
Last Answer : (D) Grashoff number
Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream
Last Answer : (A) Incurs smaller pressure drop
Description : In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat
Last Answer : (A) Loosing sensible heat
Description : Which of the following is concerned with both heat and mass transfer? (A) Lewis relationship (B) Nusselt number (C) Kutateladze number (D) Froude number
Last Answer : (A) Lewis relationship
Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature
Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column
Description : A measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the __________ number. (A) Condensation (B) Grashoff (C) Stanton (D) Brinkman
Last Answer : (D) Brinkman
Description : The ratio of momentum diffusivity to thermal diffusivity is the __________ number. (A) Prandtl (B) Nusselt (C) Stanton (D) Grashoff
Last Answer : (A) Prandtl
Description : L/G ratio in a cooling tower is a ratio of _____. • Length and girth • Length and temperature gradient • Water flow rate and air mass flow rate • Air mass flow rate and water flow rate
Last Answer : Water flow rate and air mass flow rate
Description : Pick out the wrong statement. (A) When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the ... fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process
Last Answer : (C) The operating line lies above the equilibrium curve in case of a gas desorber
Description : The __________ that are present depend on cooling tower building material, as well. Cooling towers are built of concrete, wood, plastic or metal. a. Heat b. Pollutants c. Cold d. All of Above
Last Answer : b. Pollutants
Description : A __________ is a type of heat exchange system where water is heated to its' boiling point via combustion of a fuel blown through a tube submerged in water. a. Condensate loop b. Hyperbolic cooling tower c. Steam boiler d. All of above
Last Answer : c. Steam boiler
Description : Heat load in a cooling tower (A) Means the amount of heat thrown away (KCal/hr.) by the cooling tower (B) Is equal to the number of kg, of water circulated times the cooling range (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater ... (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)
Description : In a mixer, the quantity, (v. L/D) is termed as __________ number (where, v = longitudinal velocity of material, L = length of the mixer, D = diffusivity in axial mixing). (A) Weber (B) Peclet (C) Brinkman (D) Schmidt
Last Answer : (B) Peclet
Description : The equation, (h.D/K) is called the __________ number. (A) Nusselt (B) Peclet (C) Rayleigh (D) Grashoff
Last Answer : (A) Nusselt
Description : For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) ... the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these
Last Answer : (C) Increases the overall heat transfer coefficient
Description : When the temperature and humidity of air is low, we usually use __________ draft cooling tower. (A) Natural (B) Forced (C) Induced (D) None of these
Last Answer : (A) Natural
Description : The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb
Last Answer : (A) More than the wet bulb
Description : A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height. (A) 10-15 (B) 30-40 (C) 70-80 (D) 90-100
Last Answer : (A) 10-15
Description : The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air. (A) Ambient (B) Dry bulb (C) Dew point (D) Wet bulb
Last Answer : C) Dew point
Description : Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point
Last Answer : Option A
Description : Cpµ/K is termed as the __________ number. (A) Grashoff (B) Nusselt (C) Prandtl (D) Stanton
Last Answer : (C) Prandtl
Description : NGr × NPr ) is called the __________ number. (A) Graetz (B) Rayleigh (C) Nusselt (D) Stanton
Last Answer : (B) Rayleigh
Description : Pick out the wrong statement. (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity(B) For an ideal ... D) Reaction rate does not decrease appreciably as the reaction proceeds in case of an autocatalytic reaction
Last Answer : (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity
Description : Cooling tower is a ______device a) Heat absorption b) heat rejection c) Both a and b c) neither a nor b
Last Answer : heat rejection
Description : Which one of the following is true to estimate the range of cooling tower? a) Range = cooling water inlet temperature - wet bulb temperature b) Range = cooling water outlet temperature - wet bulb temperature ... = heat load in kcal per hour / water circulation in lines per hour d) None of the above
Last Answer : Range = heat load in kcal per hour / water circulation in lines per hour
Description : The ……….-induced response of cooling tower is the key factor to improve safety and to reduce tower crack. a) wind c) heat b) water d) steam
Last Answer : wind
Description : Which of the following faction affect the cooling tower performance? • The range • Heat load • Wet bulb temperature • All of the above
Last Answer : All of the above
Description : A ______ is a specialized heat exchanger in which air and water are brought into direct contact with each otherin order to reduce the water's temperature. a. Cooling tower b. Heating tower c. Both d. All are wrong
Last Answer : cooling tower
Description : The ratio of dissolved solids in circulating water to the dissolved solids in makeup water is called a) Liquid gas ratio b) Cycle of concentration c) Cooling tower effectiveness d) None of the above
Last Answer : Cycle of concentration
Description : Cooling tower effectiveness is the ratio of a) Range/( Range + approach) b) Approach/(range + approach) c) Range /(range - approach) d) Approach/ /(range - approach)
Last Answer : Range/( Range + approach)