Understand how small changes in steam pressure affect suction capacity.
A sample chart generated from the spreadsheet shows that increasing ( P_m ) from 5 to 10 bar raises ω by ~40% for constant back pressure.
Compute the combined velocity and pressure recovery using diffuser efficiency equations (typically 4. Key Performance Variables to Watch
The area where the low-pressure process gas enters and mixes with the motive steam. ejector design calculation xls
: This document outlines the specific constants (
For complex iterations, Visual Basic for Applications (VBA) can significantly enhance your spreadsheet. VBA can automate the iterative process of finding the correct area ratio that matches your target entrainment ratio, or handle more advanced models like normal shock analysis in the diffuser. However, many 1-D models can converge using Excel's built-in iterative calculation feature (found in Options > Formulas) or by using Goal Seek.
) flows through the nozzle, converting pressure into kinetic energy (supersonic velocity). Low-pressure vapor ( Pecap P sub e ) is sucked into the mixing zone. Discharge Fluid: Combined fluids ( Pccap P sub c ) are diffused to a higher pressure. The entrainment ratio ( ) is defined as the mass flow rate of the entrained vapor ( ) divided by the mass flow rate of the motive steam ( Understand how small changes in steam pressure affect
With these resources and methods, you can turn a blank Excel workbook into a powerful, custom ejector design tool that matches your specific process needs.
An ejector uses a high-pressure motive fluid to entrain and compress a low-pressure suction fluid. The process relies entirely on the conversion of pressure energy into kinetic energy, and back into pressure energy, without any moving parts. Key Components
Designing or troubleshooting an ejector requires precise aerodynamic and thermodynamic equations. Engineers rely heavily on specialized Excel spreadsheets to automate these complex iterations. This article provides a comprehensive deep dive into the engineering principles of ejector design and outlines how to construct a robust tool. 1. Fundamental Principles of Ejector Operation Key Performance Variables to Watch The area where
A2A1=1.22×Pc-0.0739×Pp-0.81×wthe fraction with numerator cap A sub 2 and denominator cap A sub 1 end-fraction equals 1.22 cross cap P sub c to the negative 0.0739 power cross cap P sub p to the negative 0.81 power cross w
) to find the highest entrainment ratio while maintaining discharge pressure.
of the device based on the properties of the motive and suction fluids Key Content of an Ejector Design XLS
