Ejector Design Calculation Xls May 2026
For compressible fluids: [ A_t = \fracW_motiveP_1 \cdot \sqrt\frac\gammaR_gas T_1 \cdot \left(\frac2\gamma+1\right)^\frac\gamma+1\gamma-1 ] (Implemented as Excel formula with named constants)
For incompressible liquids: [ A_t = \fracW_motive\rho_1 \cdot \sqrt2 \cdot \Delta P_nozzle / \rho_1 ]
Two main approaches exist for ejector design calculations. Your .xls file should implement both with a selector switch.
Since ejector design is coupled (geometry determines ṁ_s, and ṁ_s determines geometry), use Excel’s Goal Seek or Solver:
Enable Solver via Developer tab → Add-ins → Solver Add-in.
Limitations:
Recommendations:
An ejector design calculation XLS saves hours of manual iteration and helps you avoid undersized or oversized ejectors. Whether you’re designing a new vacuum system or checking an existing one, a well-built spreadsheet is a powerful tool.
👉 Download our free Ejector Design Excel sheet – includes sample data and validation against published case studies. ejector design calculation xls
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Ejector design calculation spreadsheets typically include automated formulas to determine the entrainment ratio compression ratio physical dimensions
of the device based on the properties of the motive and suction fluids Key Content of an Ejector Design XLS
A standard calculation sheet is generally organized into the following sections: Input Parameters Motive Fluid
: Pressure, temperature, mass flow rate, and molecular weight. Suction (Entrained) Fluid : Pressure, temperature, and desired flow rate. : Required discharge pressure. Calculated Ratios Compression Ratio (
: The ratio of the compressed vapor pressure to the entrained vapor pressure. Entrainment Ratio (
: The ratio of the mass flow rate of entrained vapor to the mass flow rate of motive steam. Geometric Dimensions Nozzle Throat Area ( cap A sub 1
: Calculated using sonic velocity equations for compressible fluids. Nozzle Outlet Area ( cap A sub 2 : Based on the expansion needed to reach suction pressure. Ejector Throat Area ( cap A sub 3 For compressible fluids: [ A_t = \fracW_motiveP_1 \cdot
: The mixing section dimension required to handle the combined mass flow. Performance Metrics Isentropic Efficiency
: Accounts for frictional effects during expansion and diffusion. Steam Consumption
: The calculated amount of motive steam required to achieve the suction duty. ILF Consulting Engineers Available Resources Steam Ejector Design Calculations | PDF - Scribd
For steam ejector design calculations, several specialized Excel spreadsheets and research papers provide the necessary thermodynamic correlations for entrainment ratios and nozzle sizing. Notable Ejector Design Resources
Steam Ejector Calculation Notes: 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.
Lempor Ejector Calculator: A specialized calculator for steam locomotive exhaust systems that simplifies complex fluid dynamics into a multi-sheet Excel workbook.
Scribd - Steam Ejector Calculations XLS: This document outlines the specific constants (
) used to calculate mass flow rates of motive steam versus entrained vapor, along with area ratios for the nozzle throat and outlet. Key Design Parameters Enable Solver via Developer tab → Add-ins →
Ejector performance is typically calculated using the following variables: Entrainment Ratio (
): The mass flow rate of entrained vapor divided by the mass flow rate of motive steam. Compression Ratio ( ): The ratio of discharge pressure ( Pccap P sub c ) to entrained vapor pressure ( Pecap P sub e ). Choked flow is generally defined as Expansion Ratio ( ): The ratio of motive steam pressure ( Ppcap P sub p ) to entrained vapor pressure ( Pecap P sub e Geometry Sizing: Determining the nozzle throat area ( A1cap A sub 1 ), nozzle outlet area ( A2cap A sub 2 ), and diffuser cross-sections. Foundational Research Papers
If you are looking for the underlying theory to build your own model, the following papers are the industry standard:
"Evaluation of Steam Ejectors" by Hisham Al Dessouky et al. (Chemical Engineering & Processing, 2002): Provides the empirical constants used in most modern spreadsheets.
"Estimation of ejector's main cross sections..." (Applied Thermal Engineering, 2004): Offers a step-by-step procedure for steam-ejector refrigeration systems.
Lempor Ejector Calculator Beta 1.1 | PDF | Steam Locomotive - Scribd
If calculated P₃ is less than target, adjust:
This iteration is easily automated in Excel using Goal Seek or a lookup table.
To use the spreadsheet, simply fill in the yellow cells in the "Input" tab: