Centrifugal Compressor

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    25-May-2015
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This presentation gives the complete information about the working of centrifugal compressor.

Transcript of Centrifugal Compressor

  • 1. IntroductionClassificationCentrifugal CompressorComponentsApplicationPros & Cons

2. An air compressor is a device that converts power(usually from an electric motor, a diesel engine or agasoline engine) into kinetic energy by compressingand pressurizing air, which, on command, can bereleased in quick bursts. There are numerous methodsof air compression, divided into either positive-displacementor dynamic-displacement types. 3. AirCompressorPositiveDisplacementReciprocatingRotaryDynamicDisplacementCentrifugalAxial 4. The centrifugal air compressor isa dynamic compressor which depends on transfer ofenergy from a rotating impeller to the air.Centrifugal compressors produce high-pressuredischarge by converting angular momentum impartedby the rotating impeller (dynamic displacement).The centrifugal air compressor is an oil freecompressor by design. The oil lubricated running gearis separated from the air by shaft seals andatmospheric vents. 5. Inlet: The inlet to a centrifugal compressor is typically a simplepipe. It may include features such as a valve, stationaryvanes/airfoils (used to help swirl the flow) and both pressureand temperature instrumentation. All of these additional deviceshave important uses in the control of the centrifugal compressor.Centrifugal Impeller: The key component that makes acompressor centrifugal is the centrifugal impeller. It is theimpeller's rotating set of vanes (or blades) that gradually raisesthe energy of the working gas. This is identical to an axialcompressor with the exception that the gases can reach highervelocities and energy levels through the impeller's increasingradius. Eulers pump and turbine equation plays an importantrole in understanding impeller performance. 6. Diffuser: The next key component to the simple centrifugalcompressor is the diffuser. Downstream of the impeller in the flowpath, it is the diffuser's responsibility to convert the kinetic energy(high velocity) of the gas into pressure by gradually slowing (diffusing)the gas velocity. Diffusers can be vaneless, vaned or an alternatingcombination. High efficiency vaned diffusers are also designed over awide range of solidities from less than 1 to over 4. Hybrid versions ofvaned diffusers include: wedge, channel, and pipe diffusers. There areturbocharger applications that benefit by incorporating no diffuser.Collector: The collector of a centrifugal compressor can take manyshapes and forms. When the diffuser discharges into a large emptychamber, the collector may be termed a Plenum. When the diffuserdischarges into a device that looks somewhat like a snail shell, bull'shorn or a French horn, the collector is likely to be termeda volute or scroll. As the name implies, a collectors purpose is to gatherthe flow from the diffuser discharge annulus and deliver this flow to adownstream pipe. Either the collector or the pipe may also containvalves and instrumentation to control the compressor. 7. In gas turbines and auxiliary power units.In automotive engine and dieselengine turbochargers and superchargers.In pipeline compressors of natural gas to move the gas fromthe production site to the consumer.In oil refineries, natural gasprocessing, petrochemical and chemical plants.Air-conditioning and refrigeration and HVAC: Centrifugalcompressors quite often supply the compression in waterchillers cycles. 8. ProsCentrifugal compressors areused throughout industrybecause they have fewer rubbingparts, are relatively energyefficient, and give higher airflowthan a similarlysized reciprocatingcompressor or positive-displacementcompressor.Centrifugal compressors areoften used in small gasturbine engines like APUs(auxiliary power units) andsmaller aircraft gas turbines.ConsTheir main drawback is thatthey cannot achieve thehigh compression ratio ofreciprocating compressorswithout multiple stages.Centrifugal compressors areimpractical, compared to axialcompressors, for use in large gasturbine engines propelling largeaircraft, due to the resultingweight and stress, and to thefrontal area presented by thediffuser. 9. Thank You