Topic
Diffuser (thermodynamics)
About: Diffuser (thermodynamics) is a research topic. Over the lifetime, 6731 publications have been published within this topic receiving 54738 citations.
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Patent•
28 Aug 1997
TL;DR: In this article, an improved vacuum apparatus and method is provided which includes a vacuum body, pump or ejector which produces a plurality of high velocity liquid jet streams of a primary fluid such as water discharged into a convergent diffuser to draw a secondary fluid (gas) such as air into a vacuum chamber.
Abstract: An improved vacuum apparatus and method is provided which includes a vacuum body, pump or ejector which produces a plurality of high velocity liquid jet streams of a primary fluid (liquid) such as water discharged into a convergent diffuser to draw a secondary fluid (gas) such as air into a vacuum chamber. The secondary fluid (gas) is entrained within flow spaces formed between the liquid jet streams and is carried through the diffuser by the jet streams. A secondary fluid inlet is operatively connected to an elongate hose which serves as a vacuum line for evacuating, for example, a Mason Jar, a plastic bag, other food storage container, an oil storage or receiving receptacle, or the like. The present invention is especially adapted for use as or in a vacuum seal kit or oil change kit, but not limited thereto.
98 citations
TL;DR: In this paper, the authors used a three-dimensional Navier-Stokes code with a standard k-ε two-equation turbulence model to simulate the complex internal flow in a centrifugal pump impeller with six twisted blades.
Abstract: The current investigation is aimed to simulate the complex internal flow in a centrifugal pump impeller with six twisted blades by using a three-dimensional Navier-Stokes code with a standard k-ε two-equation turbulence model. Different flow rates were specified at inlet boundary to predict the characteristics of the pump. A detailed analysis of the results at design load, Qdesign, and off-design conditions, Q = 0.43 Qdesign and Q = 1.45 Qdesign, is presented. From the numerical simulation, it shows that the impeller passage flow at design point is quite smooth and follows the curvature of the blade. However, flow separation is observed at the leading edge due to nontangential inflow condition. The flow pattern changed significantly inside the volute as well, with double vortical flow structures formed at cutwater and slowly evolved into a single vortical structure at the volute diffuser. For the pressure distribution, the pressure increases gradually along streamwise direction in the impeller passages. When the centrifugal pump is operating under off-design flow rate condition, unsteady flow developed in the impeller passage and the volute casing.
94 citations
TL;DR: The effects of periodic excitation on the evolution of a turbulent jet were studied experimentally as discussed by the authors, where a short, wide-angle diffuser was attached to the jet exit, and excitation was introduced at the junction between the jet exiting and the diffuser inlet.
Abstract: The effects of periodic excitation on the evolution of a turbulent jet were studied experimentally. A short, wide-angle diffuser was attached to the jet exit, and excitation was introduced at the junction between the jet exit and the diffuser inlet. The introduction of high-amplitude periodic excitation at the jet exit enhances the mixing and promotes attachment of the jet shear layer to the diffuser wall. Vectoring is achieved by applying the excitation over a fraction of the circumference of the circular jet, enhancing its spreading rate on the excited side and its tendency to reattach to that side. Static-deflection studies demonstrate that the presence of the wide-angle diffuser increases the effectiveness of the added periodic momentum caused by a favorable interaction between the excitation, the jet shear layer, and the diffuser wall
94 citations
TL;DR: In this article, the authors used a laser tracking system and reverse engineering to generate a digital model of an MD-82 aircraft cabin, which was used for validating Computational Fluid Dynamics (CFD) models, including cabin geometry, boundary conditions of diffusers, and high-resolution flow field in the first-class cabin of a commercial airliner.
93 citations
Patent•
09 May 1997TL;DR: In this paper, a method for forming an aperture in a component wall made of metal, the aperture having a diffuser which opens up and outward from the bottom of the diffuser to a first surface of the wall, is presented.
Abstract: A method for forming an aperture in a component wall made of metal, the aperture having a diffuser which opens up and outward from a bottom of the diffuser to a first surface of the wall, the method includes the following steps: A) laser machining the wall with a laser which produces a laser beam having a pulse rate and power sufficient to vaporize the metal; B) firing and traversing the laser beam, preferably at an acute angle, across the surface to a predetermined first edge of the diffuser in a single pass starting at a centerline of the diffuser; and C) traversing the laser beam at an increasing rate of speed during the pass so that each beam pulse vaporizes the metal at a laser spot such that successive laser spots substantially overlap each other in decreasing amounts and the pulses nibble out the metal to form a continuous trench below the surface.
92 citations