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Diffuser (thermodynamics)

About: Diffuser (thermodynamics) is a research topic. Over the lifetime, 6731 publications have been published within this topic receiving 54738 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, particle image velocity is used to characterize the spanwise and circumferential variations in the flow features in the vaned diffuser passage of a transonic centrifugal compressor.
Abstract: An efficient diffuser is essential to a modern compressor stage due to its significance in stage performance, durability, and operability. To address the need for data that describe the complex, unsteady flow field in a vaned diffuser, particle image velocity is utilized to characterize the spanwise and circumferential variations in the flow features in the vaned diffuser passage of a transonic centrifugal compressor. The spanwise variation in the diffuser flow field is further investigated by the comparison of three different operating conditions representative of low, nominal, and high loading. These data demonstrate that not only the diffuser flow field is highly dependent on the operation conditions, e.g., hub-to-shroud variation increases with loading, but also the circumferential periodicity, created by the highly three dimensional impeller discharge flow, generates a larger unsteadiness toward the hub region of the vaned diffuser.

24 citations

Patent
21 Jan 2010
TL;DR: In this article, a diffuser and a rotor rotatably supported by the diffuser hub are used for hydroelectric power-generating, whereby a flow of fluid through the diffusers and rotor causes the rotation of the rotor and at least one magnet induces an electric current in the at least 1 coil.
Abstract: A hydroelectric power-generating apparatus comprising: (1) a fluid inlet, (2) a diffuser having (a) at least one vane supporting a diffuser hub and (b) a rotor rotatably supported by the diffuser hub and having (i) impeller blades, (ii) an impeller hub, and (iii) a shroud at the periphery of the rotor, the shroud including at least one magnet, and (3) a housing surrounding the shroud and having a rigidly-attached stator including laminations and at least one electrical coil, whereby a flow of fluid through the diffuser and rotor causes the rotation of the rotor and the at least one magnet induces an electric current in the at least one coil.

24 citations

Proceedings ArticleDOI
01 Jan 1987
TL;DR: In this article, the authors investigated the downstream boundary effects on the frequency of self-excited oscillations in two-dimensional, separated transonic diffuser flows by solving the compressible, Reynolds-averaged, thin-layer Navier-Stokes equation with a two-equation turbulence model.
Abstract: An investigation of downstream boundary effects on the frequency of self-excited oscillations in two-dimensional, separated transonic diffuser flows has been conducted numerically by solving the compressible, Reynolds-averaged, thin-layer Navier-Stokes equation with a two-equation turbulence model. It was found that the unsteady diffuser flowfields are very sensitive to the location of the downstream boundary. Extension of the diffuser downstream boundary significantly reduces the frequency and amplitude of oscillations for pressure, velocity and shock. Computational results suggest that the mechanism causing the self-excited oscillation changes from viscous convective wave dominated oscillations to inviscid acoustic wave dominated oscillations when the location of downstream boundary varies from 8.66 to 134.7 throat height. The existence of a suction slot in the experimental setup obscures the physical downstream boundary and, therefore, presents a difficulty for quantitative comparisons between computation and experiment.

24 citations

Patent
31 May 2005
TL;DR: An advanced aperture inlet (AAI) as discussed by the authors uses a three-dimensional, mixed compression inlet design derived from computational fluid dynamics (CFD) by streamline tracing a supersonic section from an axisymmetric mixed-compression inlet solution.
Abstract: An advanced aperture inlet (AAI) uses a three-dimensional, mixed compression inlet design derived from computational fluid dynamics (CFD) by streamline tracing a supersonic section from an axisymmetric mixed compression inlet solution. The axisymmetric design is used to obtain a CFD solution with slip wall boundaries at the inlet design point and serves as a flow field generator for the AAI. The AAI geometry is obtained by projecting a desired aperture shape onto a surface model of the external oblique shock. Streamline seeds are located on the projected aperture segments and transferred into the CFD solution space. The streamlines generated by these seeds inside the CFD solution space are then used as a wireframe to define the supersonic diffuser back to the throat location. Traditional design techniques are then used to define the subsonic diffuser from the inlet throat to the engine face.

24 citations

Patent
08 May 2009
TL;DR: In this paper, a diffuser and exhaust system for a turbine comprises an axial-radial diffuser, where diffuser inner and outer flow guides (10, 12) extend from an inlet to an outlet, and the exhaust hood comprises two throats or flow passages between the diffuser outlet and an exhaust hood side wall.
Abstract: A diffuser and exhaust system (1) for a turbine comprises an axial-radial diffuser and an exhaust hood (8), where diffuser inner and outer flow guides (10, 12) extend from an inlet to an outlet, and the exhaust hood (8) comprises two throats or flow passages between the diffuser outlet and an exhaust hood side wall (11'). According to the invention, the outer flow guide (12) comprises a recess (14), at one of the said two flow passages. Said flow passage is positioned in relation to a point in the exhaust hood (8) in the direction of the tangential flow velocity vector, where said point in the exhaust hood (8) is farthest away from the exhaust hood outlet (22). The recess (14) prevents a re-acceleration of the flow within the exhaust hood (8) and effects an increase in the performance of the diffuser and exhaust hood system (1).

24 citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
2021156
2020186
2019216
2018236
2017263