WorksheetsAir standard cycles / Heat transfer CO3
Total questions: 15
Worksheet time: 17mins
Choose from the following, the assumption which is not used in air standard cycles.
All processes are irreversible
The composition of working fluid does not change during any process
The values of specific heats are constants.
Air is considered as the working fluid.
Pick out the wrong statement.
Spark ignition engines are relatively light and lower in cost.
Spark ignition engines are particularly
suited for use in automobiles
In a spark-ignition engine, a mixture of fuel
and air is ignited by a spark plug
None of the above
The (a) is the distance the piston moves between TDC and BDC.
Which cycle is otherwise known as constant volume heat addition cycle?
Diesel cycle
Carnot cycle
Otto cycle
Brayton cycle
In Otto cycle, thermal efficiency increases as the
________ increases
Net work output
compression ratio
cut-off ratio
expansion ratio
For the same compression ratio and ratio of specific heats, the thermal efficiency of Diesel cycle is always _______ that of Otto cycle.
greater than
lesser than
equal to
For a given compression ratio and ratio of specific heats, the thermal efficiency of Diesel cycle _____ with increase in cut-off ratio
does not change
decreases
increases
In Brayton cycle, what is the value of thermal efficiency when the pressure ratio is equal to 1.
(a)
In regeneration Brayton cycle, the air exiting
the compressor is _____ before entering the combustor to _____ the amount of fuel.
cooled, increase
heated, increase
preheated, reduce
cooled, reduce
In convection heat transfer, the convection heat transfer coefficient is a strong function of
fluid properties
fluid velocity
all the above
In liquids and gases, the conduction results from
bulk fluid motion
transport of energy by molecular motion
all the above
Radiation heat transfer is the result of _____ emitted by a surface because of the temperature of the surface.
X-rays
gamma rays
radio waves
thermal radiation
The ability of a material to conduct heat is called
(a)
The rate at which energy is radiated by a black body at a temperature is given by _____ .
Fourier's law
Newton's law of cooling
Stefan-Boltzmann law
Kirchhoff's law
Find the rate of convection heat transfer in Watts, between a fluid at 30 degrees Celsius and a surface at 100 degrees Celsius. Take A = 2 sq. m. and h = 20 W/sq.m.K.
2500
2800
280
240
