Calculation Xls Fixed _best_ | Ejector Design

If your ejector spreadsheet still fails after these fixes, consider rebuilding it from a (e.g., ASME PTC 12.2 for steam ejectors). Excel is a tool – but the physics of choking, shocks, and mixing must be respected first.

Comprehensive Guide to Steam Jet Ejector Design Calculations

This comprehensive guide breaks down the core physics behind ejector design calculations, details how to build a fixed-geometry Excel (XLS) sizing model, and provides a troubleshooting reference for engineering applications. 1. Fundamentals of Ejector Mechanics

For a fixed-geometry ejector calculation, the physical dimensions are constant. The sheet evaluates performance based on these specific constraints: E4 ( Nozzle Exit Diameter ( ): E5 ( Mixing Throat Diameter ( ): E6 ( Tab 3: Calculation Engine (Step-by-Step Formulas) Step 1: Convert Units to SI Convert pressures from Pascalcap P a s c a l ): =B4*100000 Convert temperatures to Kelvincap K e l v i n ): =B5+273.15 Convert mass flows to : =B12/3600 Step 2: Determine Motive Flow Capacity Because the geometry is fixed ( ejector design calculation xls fixed

Em=MWactualMWair⋅TairTactualcap E m equals the square root of the fraction with numerator cap M cap W sub a c t u a l end-sub and denominator cap M cap W sub a i r end-sub end-fraction end-root center dot the square root of the fraction with numerator cap T sub a i r end-sub and denominator cap T sub a c t u a l end-sub end-fraction end-root 4. Step-by-Step Architecture for your XLS Spreadsheet

) controls the velocity of the mixed fluids before they enter the diffuser. Excel sheets use empirical area ratios based on the Compression Ratio (

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. If your ejector spreadsheet still fails after these

The core mathematical workspace executing nozzle velocity, Mach number, throat sizing, and diffuser geometry formulas.

The model must flag a "Subcritical Flow" error if the pressure ratio falls below:

At=mmCd⋅Pm⋅R⋅Tmγ⋅(2γ+1)γ+1γ−1cap A sub t equals the fraction with numerator m sub m and denominator cap C sub d center dot cap P sub m end-fraction center dot the square root of the fraction with numerator cap R center dot cap T sub m and denominator gamma center dot open paren the fraction with numerator 2 and denominator gamma plus 1 end-fraction close paren raised to the the fraction with numerator gamma plus 1 and denominator gamma minus 1 end-fraction power end-fraction end-root Cdcap C sub d = Discharge coefficient (dimensionless) = Specific heat ratio ( = Individual gas constant ( Tmcap T sub m = Motive temperature ( 3. Structural Design of a Fixed XLS Calculator The two streams begin to mix

Some of the key calculations you can perform with this XLS file include:

These models allow a spreadsheet to calculate the critical parameters listed in the table below.

Instead of manual guesswork, use Excel's built-in tools.

Use VLOOKUP against your fixed fluid databank to dynamically pull specific heat ratios based on the process gas selected. 4. Troubleshooting and Fixing Cell Reference Errors

A "fixed" spreadsheet means the formulas have been validated against real-world empirical data, accounting for friction losses and gas compressibility that basic textbook equations often overlook. Why "Fixed" Matters