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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.


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Patent
07 May 1976
TL;DR: In this article, the authors propose a manifold section for admitting inert gas such as inert gas through a diffuser formed therein which exits from an outlet aperture through a nozzle tip section, and the remaining shielding gas passes out through the outlet aperture in column fashion around the laser beam.
Abstract: A laser system includes a nozzle assembly for use in directing a shielding gas around a laser beam and thereby protecting the point of focus from contamination by the atmosphere as is useful in welding and cutting applications. The nozzle includes a manifold section for admitting a shielding gas such as inert gas through a diffuser formed therein which exits from an outlet aperture through a nozzle tip section. The geometry of the nozzle is such that a certain amount of the shielding gas is flowed backward through an inlet aperture in the manifold section and thence into a housing container reflecting mirrors for directing and focusing the laser beam through the nozzle assembly. The remaining shielding gas, which is the bulk of the gas admitted, passes out through the outlet aperture in column fashion around the laser beam. By producing a back flow of shielding gas, aspiration of air through the housing and onto the workpiece is avoided. In addition, the necessity of having alternative means for preventing such aspiration in the form of windows or lenses closing off access to the housing is also prevented. The nozzle assembly is in two parts to facilitate interchanging of nozzle tips with the manifold, thereby providing a range of outlet opening sizes.

30 citations

01 Sep 1958
TL;DR: In this article, the authors investigated the use of flat vanes in two-dimensional subsonic diffusers and found that the vanes should be symmetrically arranged in the vicinity of the diffuser throat and the vane-passage divergence angle should be approximately 7.0 degrees.
Abstract: "An investigation of the use of flat vanes in two-dimensional subsonic diffusers was made. Using optimum designs of vane installations, high pressure recoveries and steady flows were obtained for diffuser-wall divergence angles up to 42 degrees. Criteria for optimum configurations were developed which indicated that the vanes should be symmetrically arranged in the vicinity of the diffuser throat, that the vane-passage divergence angle should be approximately 7.0 degrees, and that the vanes should have a certain predictable length dependent upon the diffuser geometry" (p. 1).

30 citations

Patent
18 Jan 2010
TL;DR: In this article, a purging system for a laminar flow control system comprises an air scoop (72) and a diffuser (98) fluidly connected to a suction cavity.
Abstract: A purging system (70) for a laminar flow control system comprises an air scoop (72) and a diffuser (98) fluidly connected thereto. The air scoop is disposable into an external flow of an external atmosphere. The diffuser is configured to fluidly connect the air scoop to a suction cavity of the laminar flow control system wherein the suction cavity (38) may be disposed adjacent a porous skin (30) of an airfoil such as adjacent a leading edge (24) of the airfoil (22). The laminar flow control system may be configured to suction boundary layer flow passing over the porous skin by drawing a portion of the boundary layer flow through a plurality of pores (72) formed in the porous skin. The diffuser ducts high pressure flow captured by the air scoop to the suction cavity for discharge through the pores (36) to reduce the potential of blockage thereof.

30 citations

Journal ArticleDOI
01 Oct 2003
TL;DR: In this paper, computational work using axisymmetric, compressible, Navier-Stokes equations is carried out to predict the discharge coefficient and critical pressure ratio of gas flow through the critical nozzle.
Abstract: The critical nozzle is defined as a device to measure the mass flow with only the nozzle supply conditions making use of the flow choking phenomenon at the nozzle throat. The discharge coefficient and critical pressure ratio of the gas flow through the critical nozzle are strongly dependent on the Reynolds number, based on the diameter of the nozzle throat and nozzle supply conditions. Recently a critical nozzle with a small diameter has been extensively used to measure mass flow in a variety of industrial fields. For low Reynolds numbers, prediction of the discharge coefficient and critical pressure is very important since the viscous effects near walls significantly affect the mass flow through the critical nozzle, which is associated with working gas consumption and operation conditions of the critical nozzle. In the present study, computational work using the axisymmetric, compressible, Navier-Stokes equations is carried out to predict the discharge coefficient and critical pressure ratio of gas flow through the critical nozzle. In order to investigate the effect of the working gas and turbulence model on the discharge coefficient, several kinds of gases and several turbulence models are employed. The Reynolds number effects are investigated with several nozzles with different throat diameters. The diffuser angle is varied in order to investigate the effects on the discharge coefficient and critical pressure ratio. The computational results are compared with the previous experimental ones. It is known that the standard k-e turbulence model with the standard wall function gives the best prediction of the discharge coefficient. The discharge coefficient and critical pressure ratio are given by functions of the Reynolds number and boundary layer integral properties. It is also found that the diffuser angle affects the critical pressure ratio.

30 citations

Patent
08 Jun 1978
TL;DR: A combustor assembly for a gas turbine engine includes a tubular, multi-layered porous metal wall with pores therethrough for distribution of compressor discharge air into a combustion chamber and a rigid combustor support ring is connected to one end of the wall to receive an inlet diffuser member including an ovate inlet and a circular outlet connected to the support ring for axially directing primary air flow into the combustion chamber as discussed by the authors.
Abstract: A combustor assembly for a gas turbine engine includes a tubular, multi-layered porous metal wall with pores therethrough for distribution of compressor discharge air into a combustion chamber and wherein a rigid combustor support ring is connected to one end of the wall to receive an inlet diffuser member including an ovate inlet and a circular outlet connected to the support ring for axially directing primary air flow into the combustion chamber; and the diffuser member including a flow divider on one outer surface thereof including means for fixedly securing the inlet diffuser member with respect to a wall of a gas turbine engine and wherein coacting means are provided between the inlet diffuser member and the rigid combustor support ring of the combustor to radially connect it in place at one end thereof and wherein further coacting means are provided between the inner engine wall and a portion of the porous sleeve for axially indexing of the combustor assembly.

30 citations


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