Ejector Design Calculation Xls May 2026

Ejector Design Calculation Xls May 2026

Ejector Design Calculation using Excel

An ejector is a device used to increase the pressure of a fluid (liquid or gas) by entraining it with a high-velocity fluid, typically a gas or steam. Ejectors are widely used in various industries, including chemical processing, petroleum refining, and power generation. In this article, we'll discuss how to perform ejector design calculations using Excel.

Ejector Design Basics

Before diving into the calculations, let's review the basic components of an ejector:

  1. Nozzle: A converging nozzle where the high-velocity fluid (motive fluid) enters.
  2. Mixing Chamber: A section where the motive fluid and the fluid to be entrained (suction fluid) mix.
  3. Diffuser: A diverging section where the mixture of fluids is slowed down, converting kinetic energy into pressure energy.

Ejector Design Calculation Parameters

The following parameters are required for ejector design calculations:

  1. Motive Fluid Properties:
    • Pressure (P1)
    • Temperature (T1)
    • Flow rate (m1)
  2. Suction Fluid Properties:
    • Pressure (P2)
    • Temperature (T2)
    • Flow rate (m2)
  3. Ejector Geometry:
    • Nozzle diameter (D1)
    • Mixing chamber diameter (D2)
    • Diffuser diameter (D3)
    • Length of mixing chamber (L2)
    • Length of diffuser (L3)

Excel Calculation Template

Create an Excel template with the following sections:

  1. Input Parameters: Enter the motive fluid and suction fluid properties, as well as the ejector geometry.
  2. Thermodynamic Calculations: Calculate the thermodynamic properties of the fluids, such as density, viscosity, and specific heat capacity.
  3. Ejector Performance Calculations: Calculate the ejector performance parameters, including:
    • Entrainment ratio (ER)
    • Pressure ratio (PR)
    • Efficiency (η)
  4. Ejector Geometry Calculations: Calculate the required ejector geometry, including nozzle, mixing chamber, and diffuser dimensions.

Sample Calculations

Assuming the following input parameters:

Motive Fluid (Steam):

  • P1 = 100 bar
  • T1 = 300°C
  • m1 = 10 kg/s

Suction Fluid (Air):

  • P2 = 1 bar
  • T2 = 20°C
  • m2 = 5 kg/s

Ejector Geometry:

  • D1 = 0.05 m
  • D2 = 0.1 m
  • D3 = 0.15 m
  • L2 = 0.5 m
  • L3 = 1.0 m

Using Excel formulas and thermodynamic property tables, calculate the ejector performance parameters:

  • ER = 0.5
  • PR = 2.5
  • η = 25%

Ejector Design Calculation Example

Using the sample calculations above, the Excel template can be used to calculate the required ejector geometry:

  • Nozzle diameter (D1) = 0.05 m
  • Mixing chamber diameter (D2) = 0.085 m
  • Diffuser diameter (D3) = 0.135 m
  • Length of mixing chamber (L2) = 0.45 m
  • Length of diffuser (L3) = 0.9 m

Conclusion

Ejector design calculations can be effectively performed using Excel. By creating a comprehensive template that includes input parameters, thermodynamic calculations, ejector performance calculations, and ejector geometry calculations, engineers can quickly and accurately design ejectors for various industrial applications. The sample calculations provided demonstrate the use of Excel for ejector design calculations.

References

  • ASME Boiler and Pressure Vessel Code (BPVC)
  • API 317: Design and Installation of Venturi and Ejector Systems
  • ESDU 78005: Ejectors and Jet Pumps

Step 2 – Compute expansion ratio: ER = 7/0.1 = 70

Part 3: Building the Ejector Design Calculation .xls File

A well-structured spreadsheet contains the following 10 tabs:

3.2 Key Cell Formulas (Examples)

Motive nozzle exit Mach (choked):
[ M_e = \sqrt\frac2\gamma-1\left[ \left(\fracP_mP_exit\right)^\frac\gamma-1\gamma -1 \right] ]
Excel: =SQRT((2/(gamma-1))*((P_m/P_exit)^((gamma-1)/gamma)-1))

Area ratio from Mach:
[ \fracAA^* = \frac1M\left(\frac2\gamma+1\left(1+\frac\gamma-12M^2\right)\right)^\frac\gamma+12(\gamma-1) ]
Excel: = (1/M)*((2/(gamma+1))*(1+((gamma-1)/2)*M^2))^((gamma+1)/(2*(gamma-1)))

Entrainment ratio from momentum (constant-area mixing, no shock):
Implemented via iterative Goal Seek or explicit solve.

Building an Ejector Design Calculation XLS: Template Structure

A professional template will have six distinct worksheets:

Mastering Ejector Design Calculation Using Excel Spreadsheets (.xls): A Complete Engineering Guide

2.3 ESDU Data Sheets (Most Accurate for Industrial Use)

The Engineering Sciences Data Unit (ESDU) publication 85032 (Ejector performance) provides 30+ empirical charts. Your .xls can digitize these charts using lookup tables or polynomial regression curves. ejector design calculation xls

Step 1: Motive Nozzle Sizing

Calculate the nozzle throat area: [ A_t = \frac\dotm_1\rho_1 \cdot v_t ] where ( v_t ) is critical (sonic) velocity if the pressure ratio exceeds the critical pressure ratio.