Ejector Design Calculation Xls [Plus]
Ejector design calculations in Excel focus on determining the Entrainment Ratio Area Ratios
Step 7 – Verify entrainment ratio:
Using momentum balance (implemented in Solver), find that predicted ṁ_s = 195 kg/h → close to 200. Slightly adjust ARM to 12.8. ejector design calculation xls
Mach Number: Determining if the flow is choked at the throat ( Ejector design calculations in Excel focus on determining
5.4 Reporting with PivotTables
If you design multiple ejectors for different clients, log each design in a database sheet and analyze trends (e.g., which CR range gives highest efficiency). Critical pressure ratio: Motive 150 psig >> Suction 0
Ejector design calculation spreadsheets typically include automated formulas to determine the entrainment ratio compression ratio physical dimensions
- Critical pressure ratio: Motive 150 psig >> Suction 0.5 psia → Ratio = 300 → Underexpanded supersonic.
- Optimal area ratio ($A_t/A_n$): 12.5
- Nozzle throat diameter: 0.125 inches
- Mixing throat diameter: 0.442 inches (since area ratio = 12.5 → diameter ratio = sqrt(12.5)=3.536)
- Predicted motive steam flow: 450 lb/hr
- Entrainment ratio (Er): 0.44 lb_air / lb_steam (matches HEI standard data within 5%)
5. The Goal Seek / Solver Setup: Instead of manual iterations, set up a check cell:
- Motive: 150 psig saturated steam ($T_m = 366°F$)
- Suction: Air at 0.5 psia (25 Torr vacuum), $T_s = 80°F$
- Discharge back pressure: 15 psia
- Desired suction flow: 200 lb/hr