Consider the same situation described in Problem 9.73, but now the turbine inlet temperature is a given quantity (T₃ = 1700 K) and the heat added per unit mass, q₂–₃, is unknown.

A. Calculate the heat added per unit mass, q₂–₃, the net work per unit mass, went, and the thermal efficiency ηth as functions of the compressor pressure ratio for a range from 10 to 25. Create a single computer-generated plot of your results.

B. Discuss your results and compare them with the results of Problem 9.73.

Problem 9.73

Consider an ideal air-standard Brayton cycle operating with inlet temperature (T₁) and pressure (P₁) of 300 K and 100 kPa, respectively. The heat added per unit mass, q_2–3, is 1050 kJ/kg. Assume the following constant values of the specific heats: c_p = 1.005 kJ/kgK and c_v = 0.718 kJ/kgK. Investigate the effects of the compressor pressure ratio (P₂/P₁) by performing the tasks listed. Use a spreadsheet to perform all repetitive calculations; however, make sure that you check at least one calculation by hand.

Transcribed Image Text:

P₂ varied 2. P₁ = 100 kPa T₁ = 300 K 92-3 fixed HX HX 94-1 3 T3 = ? Wnet = ?