Higher furnace temperature cannot be achieved by use of a lean fuel gas in the furnace by_________________?
(A) Increasing the draft in the furnace
(B) Preheating the fuel gas
(C) Oxygen enrichment of combustion air
(D) Preheating the combustion air
Pick out the wrong statement?
(A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer
(B) Blowers develop a maximum pressure of 2 atmospheres
(C) Friction losses in pipe fittings are generally expressed in terms of velocity heads
(D) Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number
Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about ____________ percent?
(A) 10-15
(B) 25-30
(C) 45-50
(D) 65-70
An example of recuperative furnace is the__________________?
(A) Soaking pit
(B) Open hearth furnace
(C) Coke ovens
(D) None of these
Select the wrong statement pertaining to flow of an incompressible fluid through a Venturimeter ?
(A) For frictionless flow, the fluid pressure entering the venturi meter will be exactly equal to that leaving the Venturimeter
(B) Discharge of fluid through a Venturimeter depends upon the gage difference irrespective of the orientation of Venturimeter
(C) Venturimeter occupies less space than an orificemeter
(D) Venturimeter incurs less power loss compared to an equivalent orificemeter
Select the correct statement?
(A) The discharge through a Venturimeter depends upon Δp only and is independent of orientation of the meter
(B) A Venturimeter with a given gage difference discharges at a greater rate, when the flow is vertically downward through it, than when the flow is vertically upward
(C) For a given pressure difference, the discharge of gas is greater through a Venturimeter, when compressibility is taken into account, than when it is neglected
(D) The overall pressure loss is the same in a given pipe line, whether a Venturimeter or a nozzle with the same throat dia is used
In a furnace employing forced draught as compared to induced draught______________________?
(A) Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced
(B) The fan operates hot and hence blades are liable to corrosion and erosion
(C) Positive pressure exists in the furnace
(D) None of these
In order to maintain an oxidising atmosphere in a furnace, it should have__________________?
(A) More of excess air
(B) Less of excess air
(C) More of CO in flue gas
(D) More of CO2 in flue gas
Which is the most thermally efficient furnace _______________________?
(A) Reheating furnace
(B) Reverberatory furnace
(C) Rotary kilns
(D) Boiler furnace
Ingress of cold air in the furnaces through cracks, charging doors, openings etc ________________?
(A) Reduces the flue gas temperature and makes the furnace atmosphere oxidising
(B) Increases the load on the induced draft fan
(C) Reduces the furnace draught
(D) All