If you’d like, I can:
The diffuser converts velocity back to pressure. The fixed spreadsheet calculates recovery efficiency (η_diff) using a locked empirical model: η_diff = 0.8 - 0.002 * (Diffuser half-angle in degrees) Most broken spreadsheets ignore the half-angle limit; a fixed version prevents angles >15 degrees.
where P_d is the discharge pressure and P_s is the suction pressure.
) to high-velocity, low-pressure gas, accelerating it to supersonic speeds. Where the suction gas ( Pscap P sub s ) is entrained by the motive jet. ejector design calculation xls fixed
The spreadsheet performs the following sequential calculations based on the HEI (Heat Exchange Institute) standards: Entrainment Ratio (
Use =IF(compression_ratio < 10, "Single stage", IF(compression_ratio < 60, "Two stage", "Three stage"))
Ejectors, or injectors, operate on the Bernoulli principle and the conservation of momentum. By converting pressure energy into kinetic energy through a nozzle, they create a vacuum that pulls in surrounding gas or liquid. This "passive" reliability makes them indispensable in: for maintaining condenser vacuum. If you’d like, I can: The diffuser converts
An ejector (or eductor) is a device used to pump fluids using a high-pressure motive fluid. Designing an efficient ejector requires precise thermodynamic and fluid dynamics calculations.
Before diving into the ideal calculation structure, let’s examine why 80% of ejector spreadsheets found online are functionally broken.
Before calculating dimensions, gather your process constraints: Pressure ( Pmcap P sub m ), Temperature ( Tmcap T sub m ), Mass Flow Rate ( ), and Specific Heat Ratio ( Suction Fluid: Pressure ( Pscap P sub s ), Temperature ( Tscap T sub s ), and Molecular Weight ( MWscap M cap W sub s Discharge Fluid: Target Backpressure ( Pdcap P sub d Step 2: Calculate the Entrainment Ratio ( ERcap E cap R ) to high-velocity, low-pressure gas, accelerating it to
This is where the user enters the constraints of the process. Group inputs logically:
At 3:00 AM, the cell for "Predicted Efficiency" finally turned green. He had "fixed" the calculation by shifting from a fixed isentropic model to a polytropic efficiency model that accounted for the pressure ratio during the mixing process.
A professionally fixed ejector calculation spreadsheet must include the following seven modules. Each module is "locked" for input validation but open for output review.
Do you need the exact for fluid property lookups?
If your spreadsheet assumes supersonic flow when the pressure profile is actually sub-critical (subsonic), the geometric output will be fundamentally flawed. For steam, changes based on whether it is superheated ( ≈1.3is approximately equal to 1.3 ) or saturated/wet ( ≈1.13is approximately equal to 1.13 ). Do not use a fixed value (which is for air) across all calculations. 5. Summary Check for Validating Your Spreadsheet