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Link: Ejector Design Calculation Xls Fixed

Locked, validated formulas that prevent accidental deletion of critical logic.

The calculation relies on mass, energy, and momentum balances.

How much suction fluid can the motive fluid carry? Expansion Ratios: How the nozzle geometry affects velocity. ejector design calculation xls fixed

Calculates the final discharge velocity and pressure, ensuring the diffuser is capable of handling the mixture. Output Review: Review the calculated motive flow rate ( ṁmm dot sub m

Calculations for the relationship between the nozzle and ejector throat to ensure the design meets suction requirements. Solver/Iteration: Tools like Excel Solver Expansion Ratios: How the nozzle geometry affects velocity

A traditional fixed ejector consists of four primary sections: the primary nozzle, suction chamber, mixing chamber, and diffuser. In a "fixed" design, the throat areas and section lengths are set during manufacturing, meaning the ejector's performance is strictly a function of its boundary conditions (inlet pressures and temperatures). Key Design Parameters

In this mode, the user inputs the performance requirements as Fixed Inputs : and diffuser. In a "fixed" design

Input parameters are critical for accurate output. The Excel sheet should include: Pressure ( Ppcap P sub p ), Temperature ( Tpcap T sub p ), Molecular Weight ( MWpcap M cap W sub p ), Specific Heat Ratio ( γpgamma sub p Suction Fluid Properties: Pressure ( Pscap P sub s ), Temperature ( Tscap T sub s ), Molecular Weight ( MWscap M cap W sub s ), Specific Heat Ratio ( γsgamma sub s Discharge Pressure ( Pccap P sub c ): The required discharge pressure. Flow Rates: Required suction vapor mass flow rate ( B. Calculation Engine (The "Fixed" Equations)

Here is the typical iterative calculation sequence your spreadsheet should automate:

This diameter is a function of the combined mass flow and the desired discharge pressure. Efficiency Verification: Apply isentropic efficiency (

ER=msmm≈0.5⋅(PmPs)0.5⋅ln(PsPd)⋅MWsMWmcap E cap R equals the fraction with numerator m sub s and denominator m sub m end-fraction is approximately equal to 0.5 center dot open paren the fraction with numerator cap P sub m and denominator cap P sub s end-fraction close paren to the 0.5 power center dot l n open paren the fraction with numerator cap P sub s and denominator cap P sub d end-fraction close paren center dot the square root of the fraction with numerator cap M cap W sub s and denominator cap M cap W sub m end-fraction end-root Step 3: Size the Motive Nozzle Throat ( Atcap A sub t