Although special impeller designs are available for higher heads, a good estimate for the typical multistage compressor is approximately 10,000 ft/stage. This is based on an assumed impeller flow coefficient of 0.5 and a nominal impeller tip speed of 800 fps.
The actual head per stage varies between manufacturers and individual impeller designs, ranging from 9,000 to 12,000 feet for 28 to 30 molecular weight gas at normal temperatures.
Head per stage is limited by:
• impeller stress levels
• inlet Mach Number