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What is difference between axial flow and centrifugal LVAD?
Axial flow LVADs have a propeller-like rotor that spins along the device's long axis to propel blood forward, while centrifugal flow LVADs use a rotating impeller to draw blood into the device and then expel it outward. Centrifugal flow LVADs are generally more compact and have fewer moving parts compared to axial flow LVADs.
What is the difference between centrifugal and axial compressor?
*Axial compressors are rotating, aerofoil based compressors in which the working fluid principally flows parallel to the axis of rotation. This is in contrast with centrifugal, axi-centrifugal and mixed-flow compressors where the air may enter axially but will have a significant radial component on exit. *Axial flow compressors produce a continuous flow of compressed gas, and have the benefits of high efficiencies and large mass flow capacity, particularly in relation to their cross-section. They do, however, require several rows of aerofoils to achieve large pressure rises making them complex and expensive relative to other designs (e.g. centrifugal compressor). *Centrifugal fan/blowers are more suited to continuous-duty applications such as ventilation fans, air movers, cooling units, and other uses that require high volume with little or no pressure increase. In contrast, multi-stage reciprocating compressors often achieve discharge pressures of 8,000 to 10,000 psi (59 MPa to 69MPa). One example of an application of centrifugal compressors is their use in re-injecting natural gas back into oil fields to increase oil production. Centrifugal compressors are often used in small gas turbine engines like APUs (auxiliary power units) and smaller aircraft gas turbines. A significant reason for this is that with current technology, the equivalent flow axial compressor will be less efficient due primarily to a combination of rotor and variable stator tip-clearance losses. There are few single stage centrifugal compressors capable of pressure-ratios over 10:1, due to stress considerations which severely limit the compressor's safety, durability and life expectancy. *Compressor section location depends on the type of compressor. In the centrifugal-flow engine the compressor is between the accessory section and the combustion section; in the axial-flow engine the compressor is between the air inlet duct and the combustion section. *Centrifugal-flow compressors have the following advantages: * High pressure rise per stage. * Efficiency over wide rotational speed range. * Simplicity of manufacture with resulting low cost. * Low weight. * Low starting power requirements. They have the following disadvantages: * Large frontal area for given airflow. * Impracticality if more than two stages because of losses in turns between stages. **Axial-flow compressors have the following advantages: * High peak efficiency. * Small frontal area forgiven airflow. * Straight-through flow, allowing high ram efficiency. * Increased pressure rise due to increased number of stages with negligible losses. They have the following disadvantages: * Good efficiency over narrow rotational speed range. * Difficulty of manufacture and high cost. * Relatively high weight. * High starting power requirements (this has been partially overcome by split compressors).
How do you find centrifugal compressor is in surge?
Normaly, every centrifugal type comprssors provided with an antisurge valve or surge control valve. when compressor handelled with surge, the proveded surge control valve will become open automatically and the cycle will repeated till the comprssor is in surge.
Which method control the capacity of large centrifugal refrigerant compressor?
Capacity control in large centrifugal refrigerant compressors is typically achieved through methods such as variable inlet guide vanes, variable speed drives, and slide valves. These methods help adjust the flow of refrigerant into the compressor to modulate its capacity based on changing system requirements.
How do you calculate surge in compressor?
To calculate surge in a compressor, you would need to determine the maximum flow rate and pressure that the compressor can handle without stalling. This can be done through performance mapping or testing. Surge is typically defined as the flow rate at which the compressor stalls due to flow reversal.
The frontal area of a centrifugal compressor as compared to axial flow compressor is larger or smaller?
the frontal area of a centrifugal compresor is more as compared to axial flow compressor for a given air flow. And for this reason axial compressors are being used in aircraft engines.
What is difference between axial flow and centrifugal LVAD?
Axial flow LVADs have a propeller-like rotor that spins along the device's long axis to propel blood forward, while centrifugal flow LVADs use a rotating impeller to draw blood into the device and then expel it outward. Centrifugal flow LVADs are generally more compact and have fewer moving parts compared to axial flow LVADs.
What has the author N Suryavamshi written?
N. Suryavamshi has written: 'Unsteady flow field in a multistage axial flow compressor' -- subject- s -: Centrifugal compressors, Unsteady flow, Flow distribution
Why is the axial flow compressor better than the centrifugal compressor?
Higher peak volumetric efficiency. You don't have to turn the air at all, so you do not lose and energy in transforming it as you compress the air.
Why is the pressure ratio higher in a centrifugal compressor than an axial compressor?
There is a substantial increase in radius across the rotating blade rows of a centrifugal compressor, which is its primary distinguishing feature from the axial-flow compressors to get higher-pressure ratio. Who says the compression ratio on a centrifugal is higher than that of a screw compressor? Unless I`m not properly understanding the question, these facts are true: a screw (axial) compressor is a positive displacement machine, meaning everything that goes into it will come out. There are no losses for re-expansion etc. A centrifugal compressor`s impeller is designed with a given amount of `lift` which is basically the difference between suction and discharge pressures or compression ratio. Exceeding the designed lift capability results in a surge where the gas momentarily goes backwards through the impeller until the excess lift condition is corrected.
What is the disadvantages of centrifugal compressor?
A centrifugal pump cannot pump air, therefore cannot self prime, like a positive displacement pump.
What is the different between axial turbocharger and radial turbocharger?
An axial compressor uses many stages of "fans" with stators to compress air in the same direction as its original flow. An example of this is that of *most* turbojet engines' compressors. A radial (or centrifugal) compressor works at right angles to the airflow's original direction. An example of a radial compressor is the compressor on an automotive turbocharger.
Which is true when a radial compressor and an axial compressor with equal air flow and revolution are compared?
I don't understand the question. It would appear that you wish to compare a centrifugal compressor and an axial flow compressor operating at the same speed and delivering equal flow rates. What is the process fluid? What is the question? Is the "equal air flow" the mass flow rate? At what pressure differential would you like to consider these machines? What is it that you wish to compare? Is it weight, frontal area, mechanical efficiency, overall diameter, length, delivery temperature, input power or what?
How does a turbojet engine work?
Axial Turbojet; Air enters the engine and goes through a compressor, increasing the air's pressure and temperature. The air then enters the combustor where it is mixed with fuel and ignited. Next, the hot gas expands and spins the turbine which powers the compressor. Finally, the exhaust passes through a convergent nozzle into the atmosphere, creating a high velocity jet which pushes the aircraft. Centrifugal Turbojet; Nearly the same as an axial-flow turbojet, the centrifugal-flow turbojet compresses the air by diverting it from the axis of flow. While this type of jet is simpler, lighter and cheaper than axial-flow, it is less efficient and can not handle as high a volume of air. Often a combination of axial and centrifugal compressors are used in modern jets.
What is the difference between centrifugal and axial compressor?
*Axial compressors are rotating, aerofoil based compressors in which the working fluid principally flows parallel to the axis of rotation. This is in contrast with centrifugal, axi-centrifugal and mixed-flow compressors where the air may enter axially but will have a significant radial component on exit. *Axial flow compressors produce a continuous flow of compressed gas, and have the benefits of high efficiencies and large mass flow capacity, particularly in relation to their cross-section. They do, however, require several rows of aerofoils to achieve large pressure rises making them complex and expensive relative to other designs (e.g. centrifugal compressor). *Centrifugal fan/blowers are more suited to continuous-duty applications such as ventilation fans, air movers, cooling units, and other uses that require high volume with little or no pressure increase. In contrast, multi-stage reciprocating compressors often achieve discharge pressures of 8,000 to 10,000 psi (59 MPa to 69MPa). One example of an application of centrifugal compressors is their use in re-injecting natural gas back into oil fields to increase oil production. Centrifugal compressors are often used in small gas turbine engines like APUs (auxiliary power units) and smaller aircraft gas turbines. A significant reason for this is that with current technology, the equivalent flow axial compressor will be less efficient due primarily to a combination of rotor and variable stator tip-clearance losses. There are few single stage centrifugal compressors capable of pressure-ratios over 10:1, due to stress considerations which severely limit the compressor's safety, durability and life expectancy. *Compressor section location depends on the type of compressor. In the centrifugal-flow engine the compressor is between the accessory section and the combustion section; in the axial-flow engine the compressor is between the air inlet duct and the combustion section. *Centrifugal-flow compressors have the following advantages: * High pressure rise per stage. * Efficiency over wide rotational speed range. * Simplicity of manufacture with resulting low cost. * Low weight. * Low starting power requirements. They have the following disadvantages: * Large frontal area for given airflow. * Impracticality if more than two stages because of losses in turns between stages. **Axial-flow compressors have the following advantages: * High peak efficiency. * Small frontal area forgiven airflow. * Straight-through flow, allowing high ram efficiency. * Increased pressure rise due to increased number of stages with negligible losses. They have the following disadvantages: * Good efficiency over narrow rotational speed range. * Difficulty of manufacture and high cost. * Relatively high weight. * High starting power requirements (this has been partially overcome by split compressors).
What is surging in compressor?
Centrifugal and axial compressors will surge when forward flow through the compressor can no longer be maintained, due to an increase in pressure across the compressor, and a momentary flow reversal occurs. Once surge occurs, the reversal of flow reduces the discharge pressure or increases the suction pressure, thus allowing forward flow to resume again until the pressure rise again reaches the surge point. This surge cycle will continue until some change is made in the process or compressor conditions.
What is purpose balance line in centrifugal compressor?
The purpose of the balance line in a centrifugal compressor is to equalize the pressure between the high-pressure and low-pressure sides of the impeller. This helps to reduce axial thrust, which can lead to mechanical wear and inefficiency. By allowing a controlled flow of gas or liquid to bypass the impeller, the balance line aids in stabilizing rotor operation and improving overall performance. It is essential for maintaining the reliability and longevity of the compressor system.
