rc=(2γ+1)γγ−1r sub c equals open paren the fraction with numerator 2 and denominator gamma plus 1 end-fraction close paren raised to the the fraction with numerator gamma and denominator gamma minus 1 end-fraction power Step 3: Nozzle Geometry Calculation Rearrange the choked flow equation to solve for area. Nozzle Throat Diameter ( Dtncap D sub t n end-sub ):
If you are programming the Excel sheet manually without proprietary charts (like the HEI Standards), you can use the for gas/steam ejectors: Determine Ideal Expansion Velocity ( Vmcap V sub m ):
: Accounts for frictional effects during expansion and diffusion. Steam Consumption
The spreadsheet iteration takes less than 1 second. ejector design calculation xls
The spreadsheet calculates the motive nozzle throat area and exit area based on the expansion of steam from Pmcap P sub m to the pressure in the mixing chamber (P₃). Area: Phase 2: Mixing Chamber (Momentum Balance)
ARM = 12.5 (from interpolation)
Enable Solver via Developer tab → Add-ins → Solver Add-in. rc=(2γ+1)γγ−1r sub c equals open paren the fraction
: Pressure, temperature, mass flow rate, and molecular weight. Suction (Entrained) Fluid : Pressure, temperature, and desired flow rate. : Required discharge pressure. Calculated Ratios Compression Ratio (
Convergent-divergent (de Laval) nozzle that accelerates the motive fluid to supersonic velocities, dropping its static pressure.
The diffuser converts the high-velocity mixed fluid's kinetic energy back into pressure. Its design is key to achieving the desired discharge pressure. The spreadsheet calculates the motive nozzle throat area
dt=4⋅Atπd sub t equals the square root of the fraction with numerator 4 center dot cap A sub t and denominator pi end-fraction end-root 5. Limitations of Empirical XLS Models
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
Combines the high-velocity motive stream with the low-pressure suction stream.
Determines diffuser throat diameter and final exit cone dimensions.
Once Ar is known: [ A_2 = Ar \times A_t ] Then, [ D_2 = \sqrt\frac4 \times A_2\pi ]