Ejector Design Calculation Xls [portable] ❲TRENDING — 2027❳
Ejector Design Calculation — Write-up
Step 2: Suction Chamber Mixing
Assume constant pressure mixing (most common) or constant area mixing.
Calculate mixed fluid momentum and energy.
Step 1 – Entrainment Ratio
[ R = \fracW_suctionW_motive ] Used to determine ejector type (single-stage, multi-stage). ejector design calculation xls
Worksheet 5: Results Summary
- Optimal nozzle diameter (mm/in)
- Optimal throat diameter (mm/in)
- Predicted suction mass flow ($W_s$)
- Actual entrainment ratio vs. required
- Off-design performance curve (suction pressure vs. discharge pressure)
Step 6: Diffuser Recovery
- Isentropic efficiency ( \eta_d = 0.8 ) to 0.95
- ( P_discharge = P_after_shock \times \left(1 + \eta_d \frac\gamma-12 M_after_shock^2\right)^\gamma/(\gamma-1) )
Step 8: Output Performance
- ( \omega ), optimum area ratio, efficiency.
Worksheet 4: Mixing & Shock Analysis
- Normal shock table (automated via
IFstatements with Mach input). - Entrainment ratio iteration using the
Goal SeekorSolverExcel add-in. (Example: Set cellErto achieve target discharge pressure by changing area ratio $R_a$.)
4. Step-by-Step Calculation Procedure in Excel
2. Assumptions (example defaults)
- Motive fluid: saturated steam at 8 bar (adjustable)
- Suction fluid: saturated vapor or air at 0.5 bar
- Discharge pressure: 1.2 bar
- One-stage ejector (primary nozzle → mixing chamber → diffuser)
- Adiabatic mixing; negligible heat transfer
- Perfect gas behavior for gases; steam properties from IAPWS or steam tables
- Isentropic expansion in nozzle with nozzle efficiency η_n (typ. 0.95)
- Mixing modeled as adiabatic, constant-area or constant-pressure sections per chosen model
- Nozzle exit velocity choked if upstream conditions permit; check critical pressure
- Loss coefficients: K_m (mixing), K_d (diffuser); typical values 0.05–0.2
