| | | Output Results | | :--- | :--- | :--- | | Motive Fluid (Primary) | Pressure, temperature, mass flow rate, molecular weight, specific heat ratio, viscosity, vapor pressure | Nozzle throat diameter, nozzle exit diameter | | Suction Fluid (Secondary) | Mass flow rate, lift, pressure, temperature, molecular weight, specific heat ratio, viscosity, vapor pressure | Entrainment ratio | | Operating Conditions | Ejector type, back pressure, allowable loss coefficients (for nozzles, diffuser, etc.) | Area ratio, Mach numbers (nozzle exit, suction, mixing section), critical back pressure, discharge pressure & velocity, compression ratio, overall ejector dimensions |
from manufacturer curves (like Graham or Croll-Reynolds) for a given absolute pressure, recalibrate your mixing chamber efficiency factor ( ηmixeta sub m i x end-sub ) downward. Summary of Design Variables
executing expansion, mixing, and compression formulas. 5. Datasheet Output ejector design calculation xls fixed
The high-velocity motive jet creates a localized low-pressure zone. This pressure drop draws in the process fluid (suction fluid). The two streams begin to mix, exchanging momentum.
This is the "heart" of the calculation. The high-velocity, low-pressure motive stream mixes with the low-velocity suction stream. | | | Output Results | | :---
If you are looking to a specific calculator, I can help you dive deeper into: The specific equations (like the Thorne or Keenan models). How to program steam table lookups into your spreadsheet.
: Typically, the mixing area is sized based on a Mach number of ~1.0 (sonic flow at the throat). A rule of thumb for "Fixed" design: $$A_mix \approx A_t \times \left( 1 + \fracP_m - P_sP_s \right)^0.5$$ Or use the simplified velocity method: Velocity of Motive ($V_m$) and Suction ($V_s$) mix to create Velocity ($V_d$). $$V_d = \frac\dotm_m V_m + \dotm_s V_s\dotm_d$$ Datasheet Output The high-velocity motive jet creates a
where m_s is the suction fluid mass flow rate and m_m is the motive fluid mass flow rate.