Circulation of gases in furnace is caused by the_________________?
(A) Change in volume during a change of temperature
(B) Difference in density between hot and cold gases
(C) Furnace pressure in conjunction with draft in flues
(D) All
Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about _____________ percent?
(A) < 2
(B) < 5
(C) < 8
(D) < 10
Means for giving direction to the circulation of gases in furnaces are_____________________?
(A) Fans
(B) Arrangement of heating stock in the furnaces
(C) Location of outlet ports and heating & combustion devices
(D) All
Heat balance of furnace provides means of determining the_________________?
(A) Thermal efficiency of the process
(B) Sources of heat losses
(C) Scope of reduction of heat losses
(D) All
Pick out the wrong statement ?
(A) In a static mass of liquid, the pressure at a point is the same for all liquids
(B) Pressure decreases exponentially with elevation in an isothermal atmosphere
(C) Atmospheric pressure = absolute pressure ‒ gage pressure
(D) As per Pascal’s law, the pressure at a point in a static or uniformly moving fluid is equal in all directions
Pick out the correct statement pertaining to the flow through a converging-diverging tube ?
(A) The value of Mach number is always unity at the throat
(B) No shock wave develops in the tube when the Mach number at exit is greater than unity
(C) Throughout the converging portion of the tube, the density increases in the downstream direction
(D) None of these
If fuel and air are mixed ahead of the burner, it is called a/an ______________ burner?
(A) Premix
(B) Outside mixing type
(C) Rotary
(D) Diffusion
Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by______________________?
(A) Preheating the combustion air
(B) Oxygen enrichment of combustion air
(C) Preheating the fuel gas
(D) All
Which of the following is a directly fired intermittent furnace ?
(A) Walking beam reheating furnace
(B) Reverberatory furnace
(C) Tower furnace
(D) Tunnel kiln
In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of_________________?
(A) Transportation of coal
(B) Drying of coal
(C) Combustion of coal by supplying it around the burner
(D) Preheating the primary air