Calculation Xls [patched] | Ejector Design

Motive Fluid (High Pressure) \ v _______ ===/ \ -----------------/ Nozzle \__________________________________ Suction Fluid > Throat | Mixing Section | Diffuser > Discharge -----------------\ /‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ ===\_______/ ^ / Suction Chamber The system consists of three main components:

: 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

Engineers rely heavily on Excel spreadsheets ( .xls or .xlsx ) to automate these complex formulas. This guide explains the core engineering principles, step-by-step mathematical calculations, and structural design needed to build a robust tool. 1. Fundamentals of Ejector Operation

A complete Excel tool should include input parameters, calculated variables based on empirical correlations, and output geometries. A. Input Data Needed kPa (abs) Entrained Vapor Pressure ( Pecap P sub e ): kPa (abs) Discharge Pressure ( Pccap P sub c ): kPa (abs) Motive Temperature ( Tpcap T sub p ): K Entrained Temperature ( Tecap T sub e ): K ejector design calculation xls

the design with velocity checks (sonic at the nozzle throat). Conclusion

For , condensable mixtures , or non-ideal gases , switch to:

The velocity of the motive fluid leaving a converging-diverging nozzle throat is governed by the isentropic expansion relationship: Motive Fluid (High Pressure) \ v _______ ===/

(If you’re building your own, search for “Constant Pressure Mixing Model” – e.g., the ESDU 85032 method works well in Excel.)

Vm=2⋅kk−1⋅R⋅Tm⋅[1−(PtPm)k−1k]cap V sub m equals the square root of 2 center dot the fraction with numerator k and denominator k minus 1 end-fraction center dot cap R center dot cap T sub m center dot open bracket 1 minus open paren the fraction with numerator cap P sub t and denominator cap P sub m end-fraction close paren raised to the the fraction with numerator k minus 1 and denominator k end-fraction power close bracket end-root Vmcap V sub m = Velocity of motive fluid ( = Ratio of specific heats ( = Specific gas constant ( J/kg·KJ/kg·K Tmcap T sub m = Motive fluid temperature ( Pmcap P sub m = Motive inlet pressure ( Ptcap P sub t = Throat pressure ( The mass flow rate ( Wmcap W sub m ) through the nozzle throat area ( Atcap A sub t ) at sonic conditions (Mach 1) is:

Tip: Keep rows well-labeled with formulas written explicitly in adjacent cells for easy troubleshooting. Tab 4: Reference Data & Steam Tables Input Data Needed kPa (abs) Entrained Vapor Pressure

w equals cap A cross cap E r to the cap B-th power cross cap P sub e to the cap C-th power cross cap P sub c to the cap D-th power cross open bracket cap E plus cap F cross cap P sub p to the cap G-th power cross cap H to the cap I-th power cross cap P sub p to the cap J-th power close bracket Constants (A-J):

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