Mean effective pressure: $P_{m} = P_{1} \cdot r \cdot \frac{\eta_{th}}{r-1} = 100 \cdot 8 \cdot \frac{0.565}{8-1} = 645.7 kPa$
An Otto cycle with a compression ratio of 8 and a maximum temperature of 1000 K has a mass flow rate of 0.5 kg/s. The air enters the compressor at 300 K and 100 kPa. Determine the thermal efficiency and the mean effective pressure. thermodynamics an engineering approach chapter 9 solutions
Using the Brayton cycle equations, we can calculate the thermal efficiency and back work ratio as follows: Mean effective pressure: $P_{m} = P_{1} \cdot r
Back work ratio: $BWR = \frac{W_{comp}}{W_{turb}} = \frac{C_{p}(T_{2}-T_{1})}{C_{p}(T_{3}-T_{4})} = \frac{T_{2}-T_{1}}{T_{3}-T_{4}} = 0.429$ thermodynamics an engineering approach chapter 9 solutions