Air standard cycles / Heat transfer CO3

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