Ejector Design Calculation Xls Fixed Exclusive May 2026

Unlike variable-orifice ejectors that use a moving needle to adjust flow, a has a set nozzle diameter and throat area.

Because the geometry is fixed, the ejector will only operate efficiently at its "design point." Deviating from these parameters can lead to "choking" or "back-firing." 2. Key Parameters for the XLS Calculation

Use the isentropic expansion equation to find the Mach number. For steam, the nozzle is typically convergent-divergent (C-D) to achieve supersonic speeds. ejector design calculation xls fixed

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.

In a fixed design, the area of the mixing section determines the maximum suction flow before the unit reaches a "choked" state. Step 3: Diffuser Recovery Unlike variable-orifice ejectors that use a moving needle

Wet steam reduces the kinetic energy available at the nozzle, leading to immediate performance loss.

This article explores the fundamental engineering principles behind ejector design and how to structure a calculation spreadsheet (XLS) to ensure accurate performance modeling. 1. Understanding the Fixed-Geometry Ejector In a fixed design, the area of the

) 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

To build a robust calculation sheet, you must define the following input variables: A. Motive Fluid Properties Usually high-pressure steam or air. Temperature ( Tmcap T sub m ): Needed to determine specific volume. Flow Rate ( Wmcap W sub m ): The mass flow available to do the work. B. Suction Fluid Properties Suction Pressure ( Pscap P sub s ): The vacuum level you aim to maintain. Entrainment Ratio ( ): The ratio of suction gas to motive gas ( ). This is the most critical output of your calculation. C. Discharge Conditions Discharge Pressure ( Pdcap P sub d ): The pressure the ejector must overcome (back-pressure). 3. The Step-by-Step Calculation Process