Ejector Design Calculation Pdf Download
Ejector Design Calculation Pdf Download: A Guide for Engineers
Ejectors are devices that use a high-pressure fluid to entrain and compress a low-pressure fluid, creating a mixed fluid at an intermediate pressure. Ejectors have many applications in refrigeration, air conditioning, power generation, chemical processing, and aerospace engineering. Ejectors are simple, reliable, and energy-efficient, but they also require careful design and optimization to achieve the desired performance.
ejector design calculation pdf download
In this article, we will provide a guide for engineers who want to learn more about ejector design calculation pdf download. We will explain the basic principles of ejector operation, the different types of ejectors, the main design parameters and criteria, and the methods and tools for ejector design and performance prediction. We will also provide some examples and references for further reading.
Basic Principles of Ejector Operation
An ejector consists of three main components: a primary nozzle, a mixing chamber, and a diffuser. The primary nozzle converts the high-pressure primary fluid into a high-velocity jet that enters the mixing chamber. The jet creates a low-pressure region that entrains the low-pressure secondary fluid from the suction port. The jet and the secondary fluid mix in the mixing chamber and form a mixed fluid at an intermediate pressure. The mixed fluid then enters the diffuser, where it is decelerated and further compressed to the discharge pressure.
The performance of an ejector is usually characterized by two parameters: the entrainment ratio and the compression ratio. The entrainment ratio is defined as the mass flow rate of the secondary fluid divided by the mass flow rate of the primary fluid. The compression ratio is defined as the ratio of the discharge pressure to the suction pressure. The entrainment ratio and the compression ratio depend on the operating conditions (such as the primary pressure, the suction pressure, and the back pressure) and the geometrical parameters (such as the nozzle area ratio, the ejector area ratio, and the mixing chamber length).
Different Types of Ejectors
Ejectors can be classified into different types according to various criteria, such as the working fluids, the flow regimes, and the design configurations. Some common types of ejectors are:
Gas/gas ejectors: These ejectors use gas as both the primary and secondary fluids. They are widely used in gas compression, vacuum pumping, gas recirculation, and gas mixing applications.
Liquid/liquid ejectors: These ejectors use liquid as both the primary and secondary fluids. They are mainly used in liquid pumping, liquid mixing, and liquid extraction applications.
Steam/jet ejectors: These ejectors use steam as the primary fluid and water or another liquid as the secondary fluid. They are commonly used in refrigeration, air conditioning, and desalination systems.
Supersonic ejectors: These ejectors operate in supersonic flow regimes, where both the primary and secondary fluids reach sonic or supersonic velocities. They are typically used in aerospace engineering, such as rocket propulsion and air-breathing engines.
Constant-area mixing ejectors: These ejectors have a constant cross-sectional area in
the mixing chamber,
where
the primary nozzle exit
is located within
the cylindrical part
of
the ejector.
They are simpler
to design
but have lower performance
than constant-pressure mixing ejectors.
Constant-pressure mixing ejectors: These ejectors have a variable cross-sectional area in
the mixing chamber,
where
the primary nozzle exit
is located in
a suction chamber (usually conical)
in front of
the cylindrical part
of
the ejector.
They have higher performance
but require more complex design
than constant-area mixing ejectors.
Main Design Parameters and Criteria
The main design parameters of an ejector are:
The nozzle area ratio: This is defined as
the ratio of
the nozzle exit area
to
the nozzle throat area.
It determines
the expansion ratio
and velocity
of
the primary jet.
The ejector area ratio: This is defined as
the ratio of
the diffuser exit area
to
the nozzle throat area.
It determines
the compression ratio
and pressure recovery
of
the mixed fluid.
The mixing chamber length: This is defined as
the distance between
the nozzle exit
and
the diffuser entrance.
It determines
the degree of mixing
and entrainment
of
the secondary fluid.
The main design criteria of an ejector are:
The critical mode: This is
the operating mode
where
the mixed fluid reaches
the sonic velocity
at
the diffuser entrance.
It represents
the maximum performance
of
the ejector,
as any further increase
in back pressure
will cause
a decrease
in entrainment ratio
and compression ratio.
The optimum mode: This is
the operating mode
where
the entrainment ratio
is maximized
for a given back pressure.
It represents
the best trade-off between entrainment ratio
and compression ratio,
as any further increase
in back pressure
will cause
a decrease
in both parameters.
The efficiency: This is defined as
the ratio of
the useful work output
to
the work input
of
the ejector.
It measures
the energy conversion
and loss
of
the ejector.
The efficiency
can be calculated
by different methods,
such as
the exergy analysis,
the entropy generation analysis,
or
the coefficient of performance analysis.
Methods and Tools for Ejector Design and Performance Prediction
Ejector design and performance prediction can be performed by various methods and tools,
depending on
Ejector Design Calculation Pdf Download: A Guide for Engineers
Ejectors are devices that use a high-pressure fluid to entrain and compress a low-pressure fluid, creating a mixed fluid at an intermediate pressure. Ejectors have many applications in refrigeration, air conditioning, power generation, chemical processing, and aerospace engineering. Ejectors are simple, reliable, and energy-efficient, but they also require careful design and optimization to achieve the desired performance.
In this article, we will provide a guide for engineers who want to learn more about ejector design calculation pdf download. We will explain the basic principles of ejector operation, the different types of ejectors, the main design parameters and criteria, and the methods and tools for ejector design and performance prediction. We will also provide some examples and references for further reading.
Basic Principles of Ejector Operation
An ejector consists of three main components: a primary nozzle, a mixing chamber, and a diffuser. The primary nozzle converts the high-pressure primary fluid into a high-velocity jet that enters the mixing chamber. The jet creates a low-pressure region that entrains the low-pressure secondary fluid from the suction port. The jet and the secondary fluid mix in the mixing chamber and form a mixed fluid at an intermediate pressure. The mixed fluid then enters the diffuser, where it is decelerated and further compressed to the discharge pressure.
The performance of an ejector is usually characterized by two parameters: the entrainment ratio and the compression ratio. The entrainment ratio is defined as the mass flow rate of the secondary fluid divided by the mass flow rate of the primary fluid. The compression ratio is defined as the ratio of the discharge pressure to the suction pressure. The entrainment ratio and the compression ratio depend on the operating conditions (such as the primary pressure, the suction pressure, and the back pressure) and the geometrical parameters (such as the nozzle area ratio, the ejector area ratio, and the mixing chamber length).
Different Types of Ejectors
Ejectors can be classified into different types according to various criteria, such as the working fluids, the flow regimes, and the design configurations. Some common types of ejectors are:
Gas/gas ejectors: These ejectors use gas as both the primary and secondary fluids. They are widely used in gas compression, vacuum pumping, gas recirculation, and gas mixing applications.
Liquid/liquid ejectors: These ejectors use liquid as both the primary and secondary fluids. They are mainly used in liquid pumping, liquid mixing, and liquid extraction applications.
Steam/jet ejectors: These ejectors use steam as the primary fluid and water or another liquid as the secondary fluid. They are commonly used in refrigeration, air conditioning, and desalination systems.
Supersonic ejectors: These ejectors operate in supersonic flow regimes, where both the primary and secondary fluids reach sonic or supersonic velocities. They are typically used in aerospace engineering, such as rocket propulsion and air-breathing engines.
Constant-area mixing ejectors: These ejectors have a constant cross-sectional area in
the mixing chamber,
where
the primary nozzle exit
is located within
the cylindrical part
of
the ejector.
They are simpler
to design
but have lower performance
than constant-pressure mixing ejectors.
Constant-pressure mixing ejectors: These ejectors have a variable cross-sectional area in
the mixing chamber,
where
the primary nozzle exit
is located in
a suction chamber (usually conical)
in front of
the cylindrical part
of
the ejector.
They have higher performance
but require more complex design
than constant-area mixing ejectors.
Main Design Parameters and Criteria
The main design parameters of an ejector are:
The nozzle area ratio: This is defined as
the ratio of
the nozzle exit area
to
the nozzle throat area.
It determines
the expansion ratio
and velocity
of
the primary jet.
The ejector area ratio: This is defined as
the ratio of
the diffuser exit area
to
the nozzle throat area.
It determines
the compression ratio
and pressure recovery
of
the mixed fluid.
The mixing chamber length: This is defined as
the distance between
the nozzle exit
and
the diffuser entrance.
It determines
the degree of mixing
and entrainment
of
the secondary fluid.
The main design criteria of an ejector are:
The critical mode: This is
the operating mode
where
the mixed fluid reaches
the sonic velocity
at
the diffuser entrance.
It represents
the maximum performance
of
the ejector,
as any further increase
in back pressure
will cause
a decrease
in entrainment ratio
and compression ratio.
The optimum mode: This is
the operating mode
where
the entrainment ratio
is maximized
for a given back pressure.
It represents
the best trade-off between entrainment ratio
and compression ratio,
as any further increase
in back pressure
will cause
a decrease
in both parameters.
The efficiency: This is defined as
the ratio of
the useful work output
to
the work input
of
the ejector.
It measures
the energy conversion
and loss
of
the ejector.
The efficiency
can be calculated
by different methods,
such as
the exergy analysis,
the entropy generation analysis,
or
the coefficient of performance analysis.
Methods and Tools for Ejector Design and Performance Prediction
Ejector design and performance prediction can be performed by various methods and tools,
depending on
Conclusion
Ejectors are versatile and efficient devices that can be used for various applications involving fluid compression and mixing. However, ejector design and performance prediction are challenging tasks that require a good understanding of the underlying physical phenomena and the appropriate methods and tools. In this article, we have provided a guide for engineers who want to learn more about ejector design calculation pdf download. We have explained the basic principles of ejector operation, the different types of ejectors, the main design parameters and criteria, and the methods and tools for ejector design and performance prediction. We have also provided some examples and references for further reading. We hope that this article will help engineers to design and optimize ejectors for their specific needs and applications. 6c859133af