Question 8.6: In a single-stage compressor: Suction pressure = 101.3 kN/m²...
In a single-stage compressor: Suction pressure = 101.3 kN/m² . Suction temperature = 283 K. Final pressure = 380 kN/m². If each new charge is heated 18 deg K by contact with the clearance gases, calculate the maximum temperature attained in the cylinder.
The compression ratio = (380/101.3) = 3.75.
On the first stroke, the air enters at 283 K and is compressed adiabatically to 380 kN/m².
Thus: T_{2}/T_{1}=(P_{2}/P_{1})^{(\gamma -1)/\gamma }
= 3.75^{0.286} = 1.459
Hence, the exit temperature is: T_{2} = (1.459 × 283) = 413 K
The clearance volume gases which remain in the cylinder are able to raise the temperature of the next cylinder full of air by 18 deg K leaving the cylinder and its contents at (283 + 18) = 301 K. After compression, the exit temperature is:
T = (301 × 3.75^{0.286} ) = 439.2 K
On each subsequent stroke, the inlet temperature is always 301 K and hence the maximum temperature attained is 439.2 K.