![]() The return bend is found in multistage centrifugal compressors and is a stationary component which redirects the gas from a radially outward flow in the diffuser to a radially inward flow into the return channel which contains the next stage’s guide vanes (as previously mentioned, these vanes help to straighten and smooth the gas flow preceding the downstream impeller). As the gas exits the diffuser and enters the return bend, the gas has obtained the majority of the static pressure rise for the centrifugal stage (a centrifugal stage being the combination of the impeller and diffuser). The diffuser is a radial passage that is roughly the same width as the impeller blade, but the radial area expands and provides the desired diffusing effect. The diffuser is a stationary component which primarily converts velocity (kinetic energy) to pressure (static energy). The high velocity gas then enters the diffuser. Upon leaving the impeller, the flow has two velocity components: the first is a component in the radial direction, VR, and the second is a component in the tangential direction, VT (impeller velocity components). For the impeller with the typical backward-leaning blade, approximately two thirds of total static pressure rise of the stage is obtained within the impeller. These blades push the gas in a circular motion resulting in a static pressure rise (compression) due to the centrifugal force of rotation. Gas enters the eye of the impeller and once again makes a 90° turn resulting in a radial flow from the center of the impeller to the outer diameter.Īdditionally the gas encounters rotating blades in the impeller. The impeller spins on a shaft and is the means by which energy (work) is imparted on the gas. In the multistage centrifugal compressor, a vaned radial return channel is used to straighten and smooth gas flow preceding a 90° bend into the eye of the next impeller. This article contains excerpts from the paper, “Your Gas Compression Application – Reciprocating, Centrifugal, or Screw?” by Greg Phillippi of Ariel Corporation, Tim Manthey, Aerzen USA, Jonathan Sutter of Elliott Group, Ben Williams of Ariel Corporation and Bruce McCain, an engineering consultant, at the 2016 Turbomachinery Symposium.įor the radial-inlet compressor, an appropriate length of pipe and inlet guide vanes direct the gas towards the center of the unit before a 90° bend redirects the flow (axially) into the eye of the first impeller. ![]() In the case of an axial-inlet centrifugal compressor (typical of integrally geared units), an appropriate length of pipe serves to smooth the flow of gas into the eye of the first impeller. The defining characteristic of centrifugal compressors is that head is determined by the volume flow through the unit. Centrifugal compressors are the dynamic type, meaning that compression is accomplished through the conversion of kinetic energy to static energy. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |