Unlike centrifugal pumps, ejectors have – but their design is notoriously calculation-intensive. This is where an Ejector Design Calculation Excel Sheet becomes an engineer’s best friend.
If calculated P₃ is less than target, adjust:
The following geometric results must be clearly highlighted in your final calculation sheet to enable mechanical drafting: Controls total motive steam consumption. Nozzle Exit Diameter ( Dencap D sub e n end-sub ): Governs the expansion characteristics and Mach number. Diffuser Throat Diameter ( Dtdcap D sub t d end-sub ): Sets the velocity profile for pressure recovery.
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) : Based on the momentum velocity profile of the combined streams.
When programming or using an ejector calculation spreadsheet, keep these industrial design rules in mind:
An offers three unique advantages:
Understand how small changes in steam pressure affect suction capacity.
[Tab 1: Input Data] ---> [Tab 2: Thermodynamics] ---> [Tab 3: Geometry & Outputs] | | v v Fluid Properties, Nozzle, Mixing, & Pressures, Temps Diffuser Dimensions Tab 1: Input Parameters
An effective design spreadsheet should employ well-established thermodynamic formulas, typically based on the or Keenan and Neumann theories. Phase 1: Nozzle Design (Isentropic Expansion) ejector design calculation xls
Utilize Excel's Data Table tool or VBA arrays to plot the relationship between suction pressure and entrainment ratio. This creates the characteristic curve of the ejector. 4. Excel Implementation Matrix
). This rapid expansion drops the static pressure below that of the suction fluid, drawing the low-pressure stream into the mixing chamber. Momentum transfer occurs in the mixing section, and the combined stream enters the diffuser, where it slows down, converting kinetic energy back into static pressure higher than the suction pressure.
Follow this step-by-step logic sequence when writing formulas inside your spreadsheet: Unlike centrifugal pumps, ejectors have – but their
Dtn=4⋅Atnπcap D sub t n end-sub equals the square root of the fraction with numerator 4 center dot cap A sub t n end-sub and denominator pi end-fraction end-root Calculated using the Mach number ( Mecap M sub e ) at the expansion pressure. Step 4: Mixing Chamber and Diffuser Sizing The mixing throat area ( Atdcap A sub t d end-sub ) can be estimated using momentum balance principles: Calculate the momentum of the entering motive gas.
This sheet functions as your control dashboard. It requires cells for: Pressure ( Pmcap P sub m ), Temperature ( Tmcap T sub m ), Molecular Weight ( Mmcap M sub m ), Specific Heat Ratio ( Suction Fluid: Pressure ( Pscap P sub s ), Temperature ( Tscap T sub s ), Molecular Weight ( Mscap M sub s ), Flow Rate Requirement ( Wscap W sub s Discharge Condition: Target Discharge Pressure ( Pdcap P sub d Tab 2: Thermodynamic & Property Lookup