Steam surface condensers and vacuum systems rely heavily on ejectors (or thermocompressors) to maintain operational efficiency. When dealing with a , the design calculation becomes a precise balancing act between motive fluid pressure, suction requirements, and discharge back-pressure.
The diffuser must slow the mixed fluid down to recover pressure.
Calculate the velocity of the motive fluid as it exits the nozzle. ejector design calculation xls fixed
Unlike variable-orifice ejectors that use a moving needle to adjust flow, a has a set nozzle diameter and throat area.
Wet steam reduces the kinetic energy available at the nozzle, leading to immediate performance loss. Steam surface condensers and vacuum systems rely heavily
Use conditional formatting to highlight if the Compression Ratio ( ) exceeds stable limits (typically 10:1 for single stage).
If you are building or using a "fixed" design XLS, ensure it includes: Calculate the velocity of the motive fluid as
) does not exceed the "critical discharge pressure." If it does, the shockwave will move back into the throat, and the ejector will stop suctioning (breaking the vacuum). 4. Structuring Your XLS for Accuracy