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
Description : Which of the following is not concerned with the heat transfer? (A) Brinkman number (B) Stanton number (C) Schmidt number (D) Peclet number
Last Answer : (C) Schmidt number
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 : 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 : The ratio of momentum diffusivity to thermal diffusivity is the __________ number. (A) Prandtl (B) Nusselt (C) Stanton (D) Grashoff
Last Answer : (A) Prandtl
Description : Cpµ/K is termed as the __________ number. (A) Grashoff (B) Nusselt (C) Prandtl (D) Stanton
Last Answer : (C) Prandtl
Description : Which of the following is not applicable to liquid fuels? a) the viscosity of a liquid fuel is a measure of its internal resistance to flow. b) the viscosity of all liquid fuels decreases with ... the viscosity of liquid fuels, higher will be its heating value d) viscous fuels need heat tracing
Last Answer : c) higher the viscosity of liquid fuels, higher will be its heating value
Description : Critical value of the __________ number governs the transition from laminar to turbulent flow in free convection heat transfer. (A) Grashoff (B) Reynolds (C) Both 'a' & 'b' (D) Prandtl & Grashoff
Last Answer : (D) Prandtl & Grashoff
Description : Dittus-Boelter equation used for the determination of heat transfer coefficient is valid (A) For fluids in laminar flow (B) For fluids in turbulent flow (C) When Grashoff number is very important (D) For liquid metals
Last Answer : (B) For fluids in turbulent flow
Description : Pick out the correct statement. (A) 1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F (B) In steady state heat conduction, the only property of the substance which determines the ... in the direction of temperature rise (D) In heat transfer by forced convection, Grashoff number is very important
Last Answer : (B) In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity
Description : Leidenfrost point is a term concerned with the (A) Condensation of the saturated vapor on a cold surface (B) Concentration of a corrosive solution by evaporation (C) Heat transfer between two highly viscous liquids (D) Boiling of a liquid on a hot surface
Last Answer : (D) Boiling of a liquid on a hot surface
Description : In a heating process, a heat flow diagram in which the quantities of heat in the various items of a heat balance are represented by the width of a band is called the (A) Ostwald chart (B) Cox chart (C) Sankey diagram (D) None of these
Last Answer : (C) Sankey diagram
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 : N2 Re /NFr is called the __________ number. (A) Brinkman (B) Galileo (C) Archimedes (D) Euler
Last Answer : (B) Galileo
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 : __________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower. (A) Sherwood (B) Stanton (C) Lewis (D) Peclet
Last Answer : (C) Lewis
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 : jH factor for heat transfer is not a function of the __________ number. (A) Reynolds (B) Nusselt (C) Grashoff (D) Both (B) & (C)
Last Answer : (D) Both (B) & (C)
Description : Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in ... (A) Molal (B) Relative (C) Percentage (D) None of these
Last Answer : (A) Mola
Description : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature
Last Answer : (D) Dew point temperature
Description : Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate. (A) Elastic (B) Viscous (C) Gravity (D) None of these
Last Answer : (A) Elastic
Last Answer : A) Elastic
Description : Analogy between mass and heat transfer is not applicable in case of (A) Same velocity profile or equal eddy diffusivities (B) Thermal or pressure mass diffusion (C) Viscous heating or chemical reaction (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : The force which opposes the relative motion between different layers of liquid or gases is called – (1) Critical Velocity (2) Streamline Flow (3) Terminal Velocity (4) Viscous Force
Last Answer : (4) Viscous Force Explanation: Critical Velocity – The maximum velocity upto which fluid motion is streamline is called Critical Velocity. Streamline Flow – If velocity of all fluid particles is same all the time then it can be said in streamline flow.
Description : Nusselt number is related to Grashoff number (Gr) in turbulent & laminar flow respectively, in respect of free convection over a vertical flat plate as (A) Gr0.25, Gr (B) Gr0.25, Gr0.33 (C) Gr, Gr0.25 (D) Gr0.33, Gr0.25
Last Answer : Option A
Description : Pick out the wrong statement. (A) 'Solvates' are chemical compounds formed by solute with their solvents. When water is the solvent, then it is called a 'hydrate' (B) In heat exchanger ... vertical evaporators, area of central downtake is about 50 to 100% of the total tube cross-sectional area
Last Answer : (C) Heat transfer co-efficient during nucleate boiling is not influenced by the agitation imparted
Description : ‘L/mG’ is the expression for (A) Absorption factor (B) Brinkman number (C) Slope of operating line in absorber (D) Slope of operating line in stripper
Last Answer : (A) Absorption factor
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
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 : In natural convection heat transfer, the correlating parameter is the (A) Graetz number (B) Eckert number (C) Grashoff number (D) Bond number
Last Answer : (C) Grashoff number
Description : The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re) 0.8 (Pr) 0.4 ] cannot be used for (A) Low Reynold's number (B) Very low Grashoff number (C) Molten metals (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
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 : When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is: (A) Free convection (B) Entry length problem in laminar forced ... (developing thermal boundary layer) (C) Mixed convection (both free and forced) (D) Forced convection
Last Answer : (C) Mixed convection (both free and forced)
Description : Transition from laminar to turbulent zone in free convection heat transfer is governed by the critical value of (A) Grashoff number (B) Grashoff number & Reynolds number (C) Reynolds number (D) Grashoff number & Prandtl number
Last Answer : Option D
Description : Steam trap is used to (A) Condense the steam flowing in the pipeline (B) Remove water resulting from partial condensation of steam (C) Stop the supply of steam (D) None of these
Last Answer : (B) Remove water resulting from partial condensation of steam
Description : Smog is (A) Nothing but black smoke (B) A combination of smoke and fog (C) A liquid particle resulting from vapor condensation (D) A solid particle e.g. fly-ash
Last Answer : (B) A combination of smoke and fog
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 : NRe . NPr ) (D/L) is called the __________ number (A) Peclet (B) Stanton (C) Graetz (D) None of these
Last Answer : (C) Graetz
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 : 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) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature
Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Description : On the pressure-enthalpy diagram, condensation and de-superheating is represented by a horizontal line because theprocess (a) takes place at constant pressure (b) takes place at constant temperature (c) takes place at constant entropy (d) takes place at constant enthalpy
Last Answer : Ans: a
Description : The equation, (h.D/K) is called the __________ number. (A) Nusselt (B) Peclet (C) Rayleigh (D) Grashoff
Last Answer : (A) Nusselt
Description : Pick out the correct statement about the condensation. (A) Filmwise condensation gives a lower heat transfer rate than the dropwise condensation (B) Suitable coating or vapour additive is used to promote film ... place on it (D) Reynolds number of condensing liquid is based on its mass flow rate
Last Answer : (B) Suitable coating or vapour additive is used to promote film wise condensation
Description : Navier-Stokes equation is useful in the analysis of __________ fluid flow problems. (A) Non-viscous (B) Viscous (C) Turbulent (D) Rotational
Last Answer : (B) Viscous
Description : In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation ... Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate
Last Answer : (C) Remain unchanged
Description : In industrial operations fluids with temperature less than __________ are set as the limit for waste heat recovery because of the risk of condensation of corrosive liquids a. 80C b. 100C c. 120C d. 200C
Last Answer : 100C
Description : Viscous & heat sensitive liquids are concentrated in __________ evaporators. (A) Open pan (B) Long tube (C) Agitated film (D) None of these
Last Answer : (C) Agitated film
Description : The normal stress is the same in all directions at a point in a fluid, when the fluid is (A) Non-viscous (B) Incompressible (C) Both (A) and (B) (D) Having no motion of one fluid layer relative to the other
Last Answer : (D) Having no motion of one fluid layer relative to the other
Description : The component of acceleration resulting due to unsteady nature of flow is called __________ acceleration. (A) Normal (B) Local (C) Convective (D) Tangential
Last Answer : (B) Local