CameraIcon

SearchIcon

MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Heat Capacity at Constant Volume

The compressi...

Question

The compression ratio of a cold air-standard Otto cycle is 9. At the end of the expansion process the pressure is 655 kpa and the temperature is 550 K. The heat rejection from the cycle is $200 k J / k g$ of air. The mean effective pressure is _________ kPa (Assume $γ = 1.4$ )
1316.63

Open in App

Solution

The correct option is A 1316.63

$\begin{matrix} e t a & = 1 - \frac{1}{(r_{k})^{γ - 1}} & = 1 - \frac{1}{(9)^{0.4}} = 0.585 Q_{S} & = \frac{Q_{R}}{1 - η} = \frac{200}{1 - 0.585} = 481.93 k J / k g W_{n e t} & = Q_{S} - Q_{R} = 481.93 - 200 = 281.93 v_{1} & = v_{4} = \frac{0.287 \times 550}{655} = 0.2409 m^{3} / k g v_{2} & = \frac{v_{1}}{9} = \frac{0.2409}{9} = 0.02677 m^{3} / k g M E P & = \frac{Q_{S} - Q_{R}}{v_{1} - v_{2}} = \frac{W_{n e t}}{v_{1} - v_{2}} \frac{k J / k g}{m^{3} k g} = \frac{281.93}{0.2409 - 0.02677} = \frac{281.93}{0.21413} = 1316.63 k P a \end{matrix}$

Suggest Corrections

thumbs-up

0

Similar questions

Q. Air enters a compressor at 100 kPa and

30^{\circ} C

in a Brayton cycle. The air pressure after compression is 500 kPa. If the heat added is 623 kJ/kg, the back work ratio for the cycle is____.
(For air,

γ = 1.4 a n d C_{p} = 1.005 k J / k g K

)

Q. A Brayton cycle power plant uses a regenerator as well as reheater and intercooler. It has two stages of compression and expansion with compression starting at 103 kPa and 23°C. The pressure ratio across the compressor is 4.5. In each combustion chamber 250 kj/kg of heat is added to the air. The increase in temperature of cold air in the regenerator is 18°C. Assume isentropic process in all processes and specific heat to be constant. The total heat rejected is

Q. In an Otto cycle, air is compressed adiabatically from

27^{o} C

and 1 bar to 12 bar. heat is supplied at constant volume until the pressure rises to 35 bar. For the air

γ = 1.4, c - v = 0.718 k J / k g K

and R=0.2872 kJ/kgK. What is mean effective pressure of the cycle?

Q. The Otto cycle having compression ratio 6 and the conditions of air before isentropic compression is 1 bar and

27^{\circ} C

. The expansion process of Otto cycle is expanded further to make the ideal Atkinson cycle. The maximum pressure in both cycle is 20 bar. The difference in their efficiencies
(only magnitude) is _____%. (Take

γ

Q. An air-standard dual cycle has a compression ratio of 10. The pressure and temperature at the beginning of compressing are 1 bar and 27

^{\circ}

C. The temperature after constant volume heat addition is 987

^{\circ}

C and ned heat supplied to the cycle is 878 kJ/kg. What will be the cut-off ratio of the cycle?

[T a k e : c_{p} = 1.004 k J / k g K a n d c_{v} = 0.717 k j / k g K a n d γ = 1.4]

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Heat Capacity

CHEMISTRY

Watch in App

explore_more_icon

Explore more

Heat Capacity at Constant Volume

Standard XII Chemistry

Join BYJU'S Learning Program

CrossIcon