Topic
Diffuser (thermodynamics)
About: Diffuser (thermodynamics) is a research topic. Over the lifetime, 6731 publications have been published within this topic receiving 54738 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, particle image displacement velocimetry is applied to the measurement of fluid velocities in a centrifugal pump diffuser to define the variation of radial and tangential velocity components along a pitch.
Abstract: This work presents the application of particle image displacement velocimetry to the measurement of fluid velocities in a centrifugal pump diffuser. Measurements are taken at different operating points and allow to define the variation of radial and tangential velocity components along a pitch. They are further processed to determine the relative velocity and vorticity fields. Results are also compared with laser Doppler measurements taken in the same facility.
54 citations
TL;DR: In this article, an optimization of a vaned diffuser in a mixed-flow pump was performed by solving three-dimensional Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model, which yielded a maximum increase in efficiency of 9.75% at the design flow coefficient compared to a reference design.
Abstract: Hydrodynamic analysis and an optimization of a vaned diffuser in a mixed-flow pump are performed in this work. Numerical analysis is carried out by solving three-dimensional Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model. A validation of numerical results is conducted by comparison with experimental data for the head, power, and efficiency. An optimization process based on a radial basis neural network model is performed with four design variables that define the straight vane length ratio, the diffusion area ratio, the angle at the diffuser vane tip, and the distance ratio between the impeller blade trailing edge and the diffuser vane leading edge. Efficiency as a hydrodynamic performance parameter is selected as the objective function for optimization. The objective function is numerically assessed at design points selected by Latin hypercube sampling in the design space. The optimization yielded a maximum increase in efficiency of 9.75% at the design flow coefficient compared to a reference design. The performance curve for efficiency was also enhanced in the high flow rate region. Detailed internal flow fields between the reference and optimum designs are analyzed and discussed.
54 citations
TL;DR: In this paper, the internal flow details of a dual-bed monolith converter were determined in water-flow visualization tests run on a full-scale transparent acrylic model using steadily flowing water seeded with a small quantity of tracer particles.
Abstract: Internal flow details of a prototype dual-bed monolith converter were determined in water-flow visualization tests run on a full-scale transparent acrylic model. Using steadily flowing water seeded with a small quantity of tracer particles, fluid motion within transparent sections of the flow model was deduced from particle pathlines illuminated with a thin plane of laser light. Flow in the inlet transition separated from the diffuser walls and impinged as a constant-diameter jet on the leading face of the first monolith. Velocity profiles from streak photographs showed that the level of flow maldistribution in the first monolith was a function of Reynolds number.
53 citations
IBM1
TL;DR: In this article, the influence exerted by a nonuniform flow distribution at the inlet of oxidizers to catalytic converters on conversion efficiency evaluated channel by channel was investigated, where the flow inside the whole domain, constituted by the exhaust manifold and an elliptic cross-sectional pipe connecting it with the converter shell, was simulated by means of a three-dimensional fluid-dynamic viscous model.
Abstract: This paper focuses on the influence exerted by a nonuniform flow distribution at the inlet of oxidizers to catalytic converters on conversion efficiency evaluated channel by channel. To this aim the flow inside the whole domain, constituted by the exhaust manifold and an elliptic- cross-sectional pipe connecting it with the converter shell, is simulated by means of a three-dimensional fluid-dynamic viscous model. In this way, after assigning typical converter size and geometry (i.e., elliptic) the gas flow rate distribution can be described at its inlet surface, also varying the total mass flow rate. After calculating the flow field at converter inlet by means of a three-dimensional model, evaluation is possible of local flow distortion in comparison with the ideal conditions of constant velocity of the gas entering the honeycomb converter channels.
52 citations
Patent•
19 Nov 1999
TL;DR: In this paper, an annular manifold with a plurality of fuel emitting passages or holes disposed along the downstream side of the manifold is mounted away from the diffuser nozzle body to allow air to stream around the manifold on all sides allowing for a thorough mixture of fuel and air around the annular manifolds for better premixing in the combustion chamber.
Abstract: A fuel nozzle system for use in a combustor utilized in a combustion turbine for reducing nitrogen oxides and other pollutants including an annular fuel distribution manifold separately mounted away from a diffusion nozzle, said annular manifold having a plurality of fuel emitting passages or holes disposed along the downstream side of the manifold, said manifold being mounted in a position away from the diffuser nozzle body to allow air to stream around the manifold on all sides allowing for a thorough mixture of fuel and air around the annular manifold for better premixing in the combustion chamber.
52 citations