Question

At the beginning of the compression process of an air standard Otto cycle, p1 = 1 bar, T1 = 290 K, 1 = 400 cm3 . The maximum temperature in the cycle is 2200 K and the compression ratio is 8. Determine (a) the heat addition, in kJ. (b) the net work, in kJ. (c) the thermal efficiency. (d) the mean effective pressure, in bar.

Answer 1

To determine the heat addition, net work, thermal efficiency, and mean effective pressure in an air standard Otto cycle, we use the first law of thermodynamics, the work done in an adiabatic process, and the formulas for thermal efficiency and mean effective pressure.

Step-by-step explanation:

To determine the heat addition in the air standard Otto cycle, we need to use the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added minus the work done by the system:

ΔU = Q - W

Since the compression process is adiabatic and there is no heat transfer, the heat addition is zero (Q = 0).

The net work done by the system can be calculated using the formula for the work done in an adiabatic process:

W = (1 - (1 / γ)) * p1 * V1 * (γ - 1)

where γ is the ratio of specific heats. The thermal efficiency can be calculated using the formula:

η = 1 - (1 / (γ - 1)) * (V2 / V1)^(1 - γ)

Finally, the mean effective pressure can be calculated using the formula:

MEP = (W / V1)

Substituting the given values into the formulas, we can find the answers.