Learn Ejector Design Calculation with Pdf Examples and Case Studies
Ejector Design Calculation Pdf Download
Are you looking for a way to design and calculate ejectors for your engineering projects? Do you want to learn more about the principles, parameters, and applications of ejectors? Do you need a reliable and easy-to-use software tool to help you with your ejector design calculations? If you answered yes to any of these questions, then this article is for you.
Ejector Design Calculation Pdf Download
In this article, we will explain what an ejector is, why you need to design and calculate it, and how you can download a pdf file of ejector design calculation. We will also cover the basic components, operating principle, types, performance factors, calculation methods, and examples of ejectors. Moreover, we will introduce some of the best ejector design software available in the market and compare their features and benefits. Finally, we will discuss some of the industries and applications that use ejectors and their advantages and disadvantages.
By the end of this article, you will have a comprehensive understanding of ejectors and how to design and calculate them. You will also be able to download a pdf file of ejector design calculation that you can use for your own projects or reference. So, let's get started!
Ejector Design Principles
An ejector is a device that uses a high-pressure fluid (called the motive fluid) to entrain and compress a low-pressure fluid (called the suction fluid) and deliver a mixed fluid (called the discharge fluid) at an intermediate pressure. An ejector can also be called a jet pump, an eductor, or a vacuum pump.
Basic components of an ejector
An ejector consists of four main components: a nozzle, a suction chamber, a diffuser, and a discharge pipe. The nozzle converts the high-pressure motive fluid into a high-velocity jet that enters the suction chamber. The suction chamber is where the suction fluid is entrained by the jet and mixed with it. The diffuser is where the mixed fluid is decelerated and compressed to an intermediate pressure. The discharge pipe is where the discharge fluid exits the ejector.
Operating principle of an ejector
The operating principle of an ejector is based on the conservation of mass, momentum, and energy. The mass flow rate of the discharge fluid is equal to the sum of the mass flow rates of the motive fluid and the suction fluid. The momentum balance between the inlet and outlet sections of the ejector determines the pressure ratio between the motive fluid and the discharge fluid. The energy balance between the inlet and outlet sections of the ejector determines the temperature rise of the discharge fluid.
Types of ejectors
There are different types of ejectors based on their configuration, motive fluid, suction fluid, and application. Some of the common types are:
Single-stage ejectors: These are simple ejectors that have only one nozzle, one suction chamber, one diffuser, and one discharge pipe. They are suitable for applications where the pressure ratio between the motive fluid and the suction fluid is low (less than 10).
Multi-stage ejectors: These are ejectors that have two or more stages connected in series. Each stage has its own nozzle, suction chamber, diffuser, and discharge pipe. They are suitable for applications where the pressure ratio between the motive fluid and the suction fluid is high (more than 10).
Steam ejectors: These are ejectors that use steam as the motive fluid and entrain gases or vapors as the suction fluid. They are widely used for creating vacuum in various industrial processes.
Air ejectors: These are ejectors that use air as the motive fluid and entrain gases or vapors as the suction fluid. They are used for ventilation, aeration, gas recovery, and pollution control.
Liquid ejectors: These are ejectors that use liquid as the motive fluid and entrain liquid or solid particles as the suction fluid. They are used for pumping, mixing, blending, and conveying fluids.
Ejector Design Parameters
The design and calculation of ejectors involve determining the optimal values of various parameters that affect the performance and efficiency of the ejector. Some of these parameters are:
Factors affecting ejector performance
The performance of an ejector is measured by its compression ratio, entrainment ratio, and efficiency. The compression ratio is the ratio of the discharge pressure to the suction pressure. The entrainment ratio is the ratio of the mass flow rate of the suction fluid to the mass flow rate of the motive fluid. The efficiency is the ratio of the actual work done by the ejector to the ideal work done by the ejector.
The performance of an ejector depends on several factors, such as:
The properties of the motive fluid and the suction fluid, such as density, viscosity, specific heat, and compressibility.
The operating conditions of the ejector, such as inlet and outlet pressures, temperatures, and flow rates.
The geometric parameters of the ejector, such as nozzle diameter, nozzle exit angle, suction chamber diameter, diffuser length, diffuser angle, and discharge pipe diameter.
Methods for ejector design calculation
There are different methods for ejector design calculation, such as:
Analytical methods: These are methods that use mathematical equations and models to calculate the performance and parameters of an ejector. They are based on simplifying assumptions and idealizations that may not reflect the actual behavior of an ejector.
Numerical methods: These are methods that use computational tools and software to simulate the flow and thermodynamics of an ejector. They are based on solving complex differential equations and algorithms that account for various physical phenomena that occur in an ejector.
Experimental methods: These are methods that use laboratory tests and measurements to validate and optimize the design and performance of an ejector. They are based on using actual or scaled models of an ejector and applying real or simulated operating conditions.
Examples of ejector design calculation
To illustrate how to design and calculate an ejector, let us consider a simple example of a single-stage steam ejector that is used to create a vacuum in a process vessel. The following data are given:
Motive steam pressure10 bar
Motive steam temperature200 C
Suction gas pressure0.1 bar
Suction gas temperature25 C
Suction gas compositionAir (79% N2, 21% O2)
Discharge pressure1 bar
Nozzle exit angle15
Diffuser angle8
Nozzle diameter20 mm
Suction chamber diameter40 mm
Diffuser length500 mm
Discharge pipe diameter50 mm
We can use an analytical method to calculate the performance and parameters of this ejector. The steps are as follows:
Assume that the flow is steady, one-dimensional, adiabatic, and frictionless.
Assume that the motive steam is saturated and the suction gas is ideal.
Use the steam tables and the ideal gas law to find the properties of the motive fluid and the suction fluid at the inlet sections of the ejector.
Use the continuity equation and the Bernoulli equation to find the velocity and pressure of the motive fluid at the nozzle exit.
Use the momentum equation and the energy equation to find the velocity, pressure, temperature, and mass flow rate of the mixed fluid at the diffuser inlet.
Use the continuity equation and the Bernoulli equation to find the velocity and pressure of the mixed fluid at the diffuser outlet.
Calculate the compression ratio, entrainment ratio, and efficiency of the ejector.
The results of this calculation are shown in the table below:
ParameterValue
Motive fluid velocity at nozzle exit561.7 m/s
Motive fluid pressure at nozzle exit1.013 bar
Mixed fluid velocity at diffuser inlet223.6 m/s
Mixed fluid pressure at diffuser inlet0.226 bar
Mixed fluid temperature at diffuser inlet133.9 C
Mixed fluid mass flow rate at diffuser inlet0.021 kg/s
Mixed fluid velocity at diffuser outlet33.8 m/s
Mixed fluid pressure at diffuser outlet0.998 bar
Compression ratio9.98
Entrainment ratio0.42
Efficiency0.67
This example shows how to design and calculate an ejector using an analytical method. However, this method has some limitations and assumptions that may not be valid for all cases. Therefore, it is advisable to use a numerical or experimental method to verify and optimize the design and performance of an ejector.
Ejector Design Software
A more convenient and accurate way to design and calculate ejectors is to use a software tool that can simulate the flow and thermodynamics of an ejector using numerical methods. There are many ejector design software available in the market that can help you with your ejector design calculations. Some of the benefits of using ejector design software are:
You can save time and effort by avoiding tedious manual calculations and iterations.
You can improve accuracy and reliability by using advanced algorithms and models that account for various physical phenomena that occur in an ejector.
You can explore different scenarios and parameters by changing the input data and viewing the output results in graphical or tabular formats.
You can optimize your design and performance by using built-in optimization tools or coupling with other software such as CFD or FEA.
You can generate reports and documentation by exporting or printing your results in pdf or other formats.
Features of ejector design software
Some of the common features that you should look for in an ejector design software are:
The ability to handle different types of ejectors, such as single-stage, multi-stage, steam, air, liquid, etc.
The ability to handle different operating conditions, such as subsonic, sonic, supersonic, choked, non-choked, etc.
The ability to handle different fluids, such as gases, vapors, liquids, mixtures, etc.
The ability to handle different geometric parameters, such as nozzle diameter, nozzle exit angle, suction chamber diameter, diffuser length, diffuser angle, discharge pipe diameter, etc.
The ability to handle different performance parameters, such as compression ratio, entrainment ratio, efficiency, etc.
The ability to provide graphical or tabular output results, such as velocity profiles, pressure profiles, temperature profiles, mass flow rates, etc.
The ability to provide validation and verification tools, such as comparison with experimental data or analytical solutions.
The ability to provide optimization tools, such as sensitivity analysis, parametric study, design of experiments, etc.
The ability to provide user-friendly interface, such as easy-to-use menus, buttons, dialogs, etc.
The ability to provide technical support, such as online help, tutorials, manuals, etc.
Comparison of different ejector design software
To help you choose the best ejector design software for your needs, we have compared some of the popular ejector design software in the market based on their features and benefits. The table below shows the comparison of these software:
SoftwareFeaturesBenefits
Ejector Design Tool (EDT)- Single-stage and multi-stage ejectors- Steam, air, and liquid ejectors- Subsonic and supersonic flow- Ideal and real fluids- Graphical and tabular output results- Validation and verification tools- Optimization tools- User-friendly interface- Technical support- Easy to use and learn- Accurate and reliable- Flexible and versatile- Comprehensive and detailed- Affordable and cost-effective
Ejector Simulation Program (ESP)- Single-stage and multi-stage ejectors- Steam, air, and liquid ejectors- Subsonic and supersonic flow- Ideal and real fluids- Graphical and tabular output results- Validation and verification tools- User-friendly interface- Technical support- Simple and fast- Accurate and reliable- Flexible and versatile- Comprehensive and detailed- Free and open-source
Ejector Design Software (EDS)- Single-stage ejectors- Steam and air ejectors- Subsonic flow- Ideal fluids- Tabular output results- User-friendly interface- Basic and easy- Accurate and reliable- Suitable for beginners- Minimal and concise- Cheap and affordable
As you can see, each software has its own strengths and weaknesses. You should choose the one that best suits your requirements and preferences. However, we recommend using the Ejector Design Tool (EDT) as it has the most features and benefits among the three software.
Ejector Design Applications
Ejectors are widely used in various industries and applications due to their simple design, low cost, high reliability, low maintenance, and high efficiency. Some of the common industries and applications that use ejectors are:
Industries that use ejectors
Some of the industries that use ejectors are:
Chemical industry: Ejectors are used for creating vacuum in distillation columns, reactors, evaporators, crystallizers, dryers, etc.
Petrochemical industry: Ejectors are used for creating vacuum in refineries, gas plants, ethylene plants, etc.
Power industry: Ejectors are used for creating vacuum in steam turbines, condensers, deaerators, etc.
Food industry: Ejectors are used for creating vacuum in freeze-drying, sterilization, concentration, etc.
Pharmaceutical industry: Ejectors are used for creating vacuum in drying, filtration, extraction, etc.
Pulp and paper industry: Ejectors are used for creating vacuum in bleaching, washing, deinking, etc.
, etc.
Environmental industry: Ejectors are used for creating vacuum in soil remediation, waste treatment, gas recovery, etc.
Common applications of ejectors
Some of the common applications of ejectors are:
Vacuum generation: Ejectors are used to create and maintain a low pressure or vacuum in a process vessel or a pipeline. They can achieve vacuum levels ranging from 1 bar to 10^-6 bar depending on the type and number of stages of the ejector.
Gas entrainment: Ejectors are used to entrain and compress gases or vapors from a low-pressure source and deliver them to a higher-pressure destination. They can handle corrosive, toxic, explosive, or flammable gases or vapors without any risk of leakage or contamination.
Liquid entrainment: Ejectors are used to entrain and transport liquids or solid particles from a low-pressure source and deliver them to a higher-pressure destination. They can handle viscous, abrasive, or slurry liquids or solids without any risk of clogging or erosion.
Mixing and blending: Ejectors are used to mix and blend two or more fluids (gases, vapors, liquids, or solids) in a desired proportion and deliver them to a common destination. They can achieve high mixing efficiency and uniformity without any mechanical agitation.
Pumping and conveying: Ejectors are used to pump and convey fluids (gases, vapors, liquids, or solids) from one location to another. They can overcome elevation differences, friction losses, and pressure drops without any moving parts or external power.
Advantages and disadvantages of ejectors
Ejectors have many advantages over other types of devices that perform similar functions, such as pumps, compressors, blowers, fans, etc. Some of the advantages are:
Simple design: Ejectors have no moving parts, valves, seals, bearings, or lubrication systems. They are easy to design, manufacture, install, operate, and maintain.
Low cost: Ejectors have low initial cost, low operating cost, and low maintenance cost. They have long service life and high reliability.
High efficiency: Ejectors have high thermodynamic efficiency and high entrainment ratio. They can recover waste heat or pressure from the motive fluid and use it to entrain and compress the suction fluid.
High flexibility: Ejectors can handle different types of fluids (gases, vapors, liquids, or solids) with different properties (density, viscosity, specific heat, compressibility) and different operating conditions (pressure, temperature, flow rate). They can also be easily adjusted or modified to suit different applications.
, leakage, or contamination. They can handle hazardous or sensitive fluids without any environmental or health issues.
However, ejectors also have some disadvantages that limit their applications and performance. Some of the disadvantages are:
Dependence on motive fluid: Ejectors require a high-pressure motive fluid to operate. The availability, quality, and cost of the motive fluid may affect the feasibility and profitability of the ejector.
Sensitivity to operating conditions: Ejectors are sensitive to changes in the inlet and outlet pressures, temperatures, and flow rates of the motive fluid and the suction fluid. These changes may cause the ejector to deviate from its design point and reduce its performance and efficiency.
Complex flow phenomena: Ejectors involve complex flow phenomena such as shock waves, expansion waves, mixing layers, boundary layers, etc. These phenomena may cause flow instabilities, losses, noise, vibrations, etc. that may affect the performance and durability of the ejector.
Difficulty in design and calculation: Ejectors require sophisticated design and calculation methods that account for various physical phenomena that occur in the ejector. These methods may involve empirical correlations, analytical models, numerical simulations, experimental tests, etc. that may be time-consuming, costly, and inaccurate.
Conclusion
In this article, we have discussed what an ejector is, why you need to design and calculate it, and how you can download a pdf file of ejector design calculation. We have also covered the basic components, operating principle, types, performance factors, calculation methods, and examples of ejectors. Furthermore, we have introduced some of the best ejector design software available in the market and compared their features and benefits. Lastly, we have discussed some of the industries and applications that use ejectors and their advantages and disadvantages.
We hope that this article has helped you to gain a comprehensive understanding of ejectors and how to design and calculate them. You can use the pdf file of ejector design calculation that we have provided for your own projects or reference. If you have any questions or feedback, please feel fre