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Surge is defined as the operating point at which the compressor peak head capability and minimum flow limit are reached. The compressor loses the ability to maintain the peak head when surge occurs and the entire system becomes unstable. Under normal conditions, the compressor operates to the right of the surge line. However, as fluctuations in flow rate occur, or under startup / emergency shutdown, the operating point will move towards the surge line because flow is reduced. If conditions are such that the operating point approaches the surge line, the impeller and diffuser begin to operate in stall and flow recirculation occurs. The flow separation will eventually cause a decrease in the discharge pressure and flow from suction to discharge will resume. This is defined as the surge cycle of the compressor.
The surge cycle will repeat itself unless control systems are installed or operational changes are made to bring the compressor out of the surge cycle. The surge cycle may result in a small or large flow reversal period depending on the discharge gas volume and the pressure ratio. Chronic surge is characterized by intermittent periods of small flow reversal that may not cause severe damage to the machine. Acute surge is more pronounced, usually due to a rapid transition across the surge line. Any surge event can cause severe damage to the thrust bearings, seals, and the impeller.
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Why is axial and centrifugal compressors combined together?
Axial and centrifugal compressors are often combined to leverage their complementary strengths. Axial compressors provide high efficiency and are effective for handling large volumes of air at lower pressure ratios, while centrifugal compressors excel at achieving high pressure ratios in a compact design. Together, they enhance overall system performance, enabling applications that require a wide range of operating conditions, such as in aircraft engines and industrial gas turbines. This combination allows for improved efficiency, flexibility, and performance across various operating scenarios.
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 are the advantages and disadvantages of axial compressor?
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).
Why refrigerator compressors are belt driven?
The compressors are of both types, belt driven and direct compressor. The belt driven compressors are because of the higher requirement which is not possible by direct compressors and being un economical.
What is compressor snubber?
Snubber is Pulsation damper that is installed on suction and discharge of compressors. It provides a continuous stream on reciprocating compressors.
Why is axial and centrifugal compressors combined together?
Axial and centrifugal compressors are often combined to leverage their complementary strengths. Axial compressors provide high efficiency and are effective for handling large volumes of air at lower pressure ratios, while centrifugal compressors excel at achieving high pressure ratios in a compact design. Together, they enhance overall system performance, enabling applications that require a wide range of operating conditions, such as in aircraft engines and industrial gas turbines. This combination allows for improved efficiency, flexibility, and performance across various operating scenarios.
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 the difference of an axial flow and centrifugal compressor?
The centrifugal flow compressor has a single or two stage unit using an impeller. The axial flow compressor is a multi-stage unit using alternate rows of rotating (rotor) blades and stationary (stator) vanes.
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).
Disadvantages of centrifugal compressor in gas turbine?
This relationship is the reason advances in turbines and axial compressors often find their way cutaway showing an axi-centrifugal compressor gas turbine.
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
What has the author Franklin K Moore written?
Franklin K. Moore has written: 'Research on rotating stall in axial flow compressors. Part IV. A preliminary study of three-dimensional rotating stall'
How do use surging in a sentence?
the water was surging over the rocks
What type of compressors do you service?
Lubricated Screw Air Compressors Oil Free Screw Air Compressors Reciprocating Air Compressors Portable Air Compressors High-pressure compressors Medical Air Compressors Compressed Air Dryers Vacuum Pumps Compressed Air Treatment
What are the advantages and disadvantages of axial compressor?
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 are application of Axial flow compressors?
1. Blast furnaces 2. Air separation plants 3. Fluid catalytic cracking units 4. Nitric acid plants 5. Jet-engine test facilities
What is tHe purpose of inlet guide vanes in gas turbine?
In axial flow compressors, the primary purpose of IGVs (fixed or variable) is to guide the airflow onto the first stage rotor blades at an appropriate or required angle of attack.
