: This is a widely used free spreadsheet on Cheresources based on semi-empirical equations for entrainment ratio. It uses curve-fitting constants for both choked and non-choked flow conditions.
A comprehensive article on ejector design identifies these sequential steps for calculation: Archive ouverte HAL Step 1: Entrainment Ratio ( Ejectors (2022) | Ipieca ejector design calculation xls
Often incorporates logarithmic terms of the pressure ratios to account for subsonic behavior. Geometric Parameters (Area Ratios) : Calculates cross-sectional areas for: Nozzle Throat ( cap A sub 1 Where motive fluid reaches sonic speed. Nozzle Outlet ( cap A sub 2 Optimized for the expansion to suction pressure. Ejector Throat/Mixing Tube ( cap A sub 3 Where motive and suction fluids combine. Specialized Calculators Steam Jet Ejectors : Professional sheets like those from Graham Corporation : This is a widely used free spreadsheet
A robust spreadsheet typically follows these sequential calculations: Key Formula/Logic Compression Ratio ( CRcap C cap R ) Assess performance feasibility 2 Expansion Ratio ( ERcap E cap R ) Determine motive energy 3 Entrainment Ratio ( ) Calculate suction capacity (Use semi-empirical constants A–H) 4 Nozzle Sizing Find throat ( A1cap A sub 1 ) & outlet area ( A2cap A sub 2 and isentropic expansion 5 Mixing & Diffuser Find mixing diameter ( A3cap A sub 3 Function of combined mass flow and Pccap P sub c 3. Critical Formulas for Excel Use these semi-empirical equations (valid for ) in your cells: Entrainment Ratio ( ): Constants (approximate): Nozzle Throat Area ( A1cap A sub 1 ): 4. Implementation Resources ejector design calculation xls
Calculate the nozzle throat area: [ A_t = \frac\dotm_1\rho_1 \cdot v_t ] where ( v_t ) is critical (sonic) velocity if the pressure ratio exceeds the critical pressure ratio.
): The ratio of entrained vapor mass flow rate to motive steam mass flow rate ( Step-by-Step Calculation Logic for Excel