Showing papers on "Diffuser (thermodynamics) published in 1983"

The response of normal shocks in diffusers

Abstract: The frequency response of a normal shock in a diverging channel is calculated for application to problems of pressure oscillations in ramjet engines. Two limits of a linearized analysis arc discussed: one represents isentropic flow on both sides of a shock wave; the other may be a crude appr'l'I;imation to the influence of flow separation induced hy the wave. Numerical results arc given, and the influences of the shock wave on oscillations in the engine are discus,ed.

Apparatus for periodically oxidizing particulates collected from exhaust gases

Abstract: An apparatus for regenerating a filter trap (A) used to collect particulates from the exhaust gas of an internal combustion engine. The apparatus comprises: (a) apparatus (C-2) providing a flow of a heat transfer medium through the filter trap (A), (b) apparatus (C) for heating the heat transfer medium to a temperature effective to incinerate the particulates in the filter trap (A), and (c) a flow mask (22) stationed in the flow of heat transfer medium, upstream from said filter trap (A) effective to divert the heat transfer medium away from the radially inner zone of the filter trap (A) while guiding the heat transfer medium to engage and ignite the particulates along a radially outer region of the filter trap (A). The mask (22) is a circular disc and spaced upstream from the filter trap (A) effective to mask a central core area of the flow of heat transfer medium. The apparatus (C) for heating comprises one or more electrically heated resistance elements (21) arranged in a planar coil configuration extending transversely across the flow of heat transfer medium. A flow diffuser (23) is stationed upstream from the mask (22) and is comprised of a plurality of foraminous plates effective to diffuse and slow down the flow of heat transfer medium for increasing heat exchange. The flow diffuser (23) has a radiation reflective coating to limit heat losses and a member (24) is employed for depressing the temperature required to ignite the particulates.

Pressure variation absorber

Abstract: Pressure variation absorbing apparatus is mounted adjacent to a moving fluid stream in the diffuser of a centrifugal compressor for absorbing both acoustic and aerodynamic pressure variations. The absorbing apparatus when mounted as a part of the diffuser wall of a centrifugal compressor not only reduces acoustic noise but also absorbs aerodynamic pressure variations increasing the efficiency of the compressor and simultaneously reducing the rate of flow at which surge occurs thereby enlarging the operational flow range of the compressor. A method of absorbing pressure variations in a moving fluid stream is also disclosed.

Performance Comparison of Straight and Curved Diffusers

Abstract: Experimental studies have been carried out to compare the performance of two dimensional straight and curved diffusers of same area ratio and effective divergence angle in the Reynolds number range of 7.8 X 10(5) to 1.29 X 10(6). Free stream turbulence effects have also been studied at the increased turbulence level to 3.4 per cent. The results indicate that straight diffuser pressure recovery is slightly higher as compared to the curved diffusers. However, stream turbulence, which improves the pressure recovery in both cases, has been observed to have greater effect in case of curved diffuser. Boundary layer velocity profiles on the diffuser surfaces have also been presented at various streamwise stations. It is observedthat the growth of inner surface boundary layer has a major effects on losses in case of a curved diffuser.

Numerical solution of the Navier-Stokes equations for compressible turbulent two/three dimensional flows in the terminal shock region of an inlet/diffuser

Abstract: The multidimensional ensemble averaged compressible time dependent Navier Stokes equations in conjunction with mixing length turbulence model and shock capturing technique were used to study the terminal shock type of flows in various flight regimes occurring in a diffuser/inlet model. The numerical scheme for solving the governing equations is based on a linearized block implicit approach and the following high Reynolds number calculations were carried out: (1) 2 D, steady, subsonic; (2) 2 D, steady, transonic with normal shock; (3) 2 D, steady, supersonic with terminal shock; (4) 2 D, transient process of shock development and (5) 3 D, steady, transonic with normal shock. The numerical results obtained for the 2 D and 3 D transonic shocked flows were compared with corresponding experimental data; the calculated wall static pressure distributions agree well with the measured data.

Calculation of various diffuser flows with inlet swirl and inlet distortion effects

Abstract: A method of predicting the properties of various turbulent flows in planar, conical, and annular diffusers with inlet swirl and inlet distortion effects has been developed and appraised. The numerical scheme is based on the fully conservative control volume representation of governing conservation equations. The method is capable of carrying out the calculation when the flowfield contains stalled or recirculation flow regions. Three different discretization schemes are compared to analyze the numerical diffusion. An algebraic Reynolds stress model is used to represent the large streamline curvature. The appraisal is achieved by comparing predicted results with various experimental data. The results show that the numerical scheme with the utilized turbulence closure model predicts various diffuser flows with the effects of inlet swirl and inlet distortion within measurement accuracy and is able to provide various guiding information for many engineering applications.

Perforated plate for evening out the velocity distribution

Abstract: In a perforated plate (1) for evening out the velocity distribution in a flow channel, the passage holes (2) are designed as shock diffusers arranged in parallel. For this purpose, they are provided with an inlet diameter (d) on the inflow side (3) and with a larger outlet diameter (D) on the outflow side (4) of the perforated plate. Due to this design, a relatively large blocking (area ratio of blocked flow cross-section to the free flow cross-section) on the inflow side and a relatively small blocking on the outflow side of the perforated plate are obtained. To ensure a shock diffuser effect, the length of the outlet holes must be sized such that the flow makes contact again before the outlet edge thereof. Important advantages of this perforated plate are that, with a relatively low pressure drop coefficient, a very good evening-out effect and a short back-flow zone on the outflow side of the perforated plate are achieved. Perforated plates of this type are used in the construction of turbo machines, in particular in gas turbines.

Fluid diffuser for gases and liquids

Abstract: A fluid diffuser for dispersing a gas or liquid into a body of receiving liquid in which it is immersed. The diffuser includes a rotatable shaft, a thin disk-like member mounted for rotation on the shaft, and an annular ring positioned adjacent the outer perimeter of the disk-like member. At least one of the top and bottom walls of the annular ring is porous. These top and bottom walls define a fluid plenum, into which gas or liquid under pressure is introduced to be emitted from the plenum as small, nascent fluid spheroids on the surface of the annular ring. The boundary layer flow from rotation of the disk-like member within the body of receiving liquid shears fine gas bubbles or liquid particles from the foraminous surface or surfaces of the annular ring. The annular ring may be fixed, or rotatable in the opposite annular direction from the rotation of the disk. Impeller blades may be mounted on the top and/or bottom surfaces of the rotatable disk. The fluid diffuser is disclosed immersed in a flotation tank with a system of baffles to define a mixing zone at the bottom of the tank and a flotation zone at the top of the tank. Preferred embodiments of the diffuser include features to improve the mixing as well as diffusing action of the device.

Inhalation device with dosage means

Abstract: 1. Inhalator device comprising a dosage mechanism for inhalates using an inhalator tank (4, 4') closed hermetically containing an inhalator fluid (3) exposed pressure, which tank is provided with a nozzle (6, 6') directed to the area of a diffuser element (1, 1'), through which nozzle by opening of a valve attached to the nozzle the inhalator fluid (3) comes from the tank (4, 4') to the diffuser element (1, 1'), characterized in that the valve (8, 8') is a valve controlable by a time control arrangement (13) and in that the elastical pressure acting to the inhalator fluid (3) is the exclusive conveying pressure for the inhalator fluid.

High blockage diffuser with means for minimizing wakes

Abstract: This invention minimizes wakes manifested by a fuel nozzle support structure extending through an annular diffuser engine to the burner in a gas turbine engine, spaced walls extending from the inner and outer wall of the diffuser project toward the nozzle support downstream of the support that passes transverse to the flow, one wall being shaped conically and the other being shaped bell-mouthed and convergent.

Diffuser of centrifugal type fluid machine

Abstract: PURPOSE: To improve efficiency by jetting a portion of pressurized fluid in a diffuser outlet from the blade plate at the negative pressure surface side of vane through jetting paths provided in the blade plate at the negative pressure surface side of vane to restrain the exfoliation of flow produced on the negative pressure surface. CONSTITUTION: A blade plate 3b 2 at the negative pressure side of a diffuser vane 3b consisting of two blade plates 3b 1 , 3b 2 is provided near a vane inlet with a jetting path 10. Thus, a portion of high pressure fluid 7b at a diffuser outlet flows inside the vane 3b, i.e. between the vanes 3b 1 , 3b 2 and then is jetted through the path 10 to the surface of the upstream side vane 3b to flow out as stream 7c. By producing such jet stream 7c is activated a boundary layer on the vane negative pressure surface to restrain the exfoliation of flow, delay stalling and expand operative range for improving efficiency. COPYRIGHT: (C)1984,JPO&Japio

Optical system with diffuser for transformation of a collimated beam into a self-luminous arc with required curvature and numerical aperture

Abstract: Apparatus for producing a line source of a desired shape from a light source such as an excimer laser comprising means for directing the light source along a predetermined path to a cylindrical lens positioned to produce a virtual line image having uniform intensity along its length at a first location. However, the image is intercepted by a cylindrical mirror inclined at an angle so that the beam is transformed into a curved shape and directed onto a quartz diffuser. This apparatus produces a curved self-luminous distribution having uniform intensity over its length. In a specific embodiment, the diffuser is a directional diffuser.

Investigation of tangential blowing applied to a subsonic V/STOL inlet

Abstract: Engine inlets for subsonic V/STOL aircraft must operate over a wide range of conditions without internal flow separation. An experimental and an analytical investigation were conducted to evaluate the effectiveness of tangential blowing to maintain attached flow to high angles of attack. The inlet had a relatively thin lip with a blowing slot located either on the lip or in the diffuser. The height and width of these slots were varied. Experimentally determined flow separation boundaries showed that lip blowing achieved higher angle-of-attack capability than diffuser blowing. This capability was achieved with the largest slot circumferential extent and either of the two slot heights. Predicted (analytical) separation boundaries showed good agreement except at the highest angles of attack.

Microwave boiler for the production of a heated fluid for domestic or industriel use or for room heating, and process used by this boiler

Abstract: 1. A microwave boiler producing hot fluids for domestic or industrial use or for room heating, comprising a metallic conducting and/or absorbing chamber (7) containing a fluid to be heated (6), a source of microwave energy (2) of the klystron or magnetron type, a device (3) of the waveguide, coaxial cable or similar type, transmitting said energy from the source (2) to the chamber (7) and a diffuser (5) which is fluid-tight and permeable to the waves, characterised in that, the fluid to be heated being a particular fluid among a plurality of fluids - particularly industrial oils -, between said device (3) of the waveguide type and said chamber (7) is interposed an applicator device (4) which co-operates with said chamber (7) in such a manner that it enables said microwave energy to be applied to said particular fluid (6) at a frequency corresponding to the natural frequency of relaxation oscillation of the particular fluid in question at a given temperature, said applicator device (4) being closed by said diffuser (5) which is fluid-tight and permeable to the waves, said applicator device (4) radiating said microwave energy towards said particular fluid (6) to be heated.

Car air-conditioner

Abstract: PURPOSE:To perform the cooling and the hot air exhausion through the inner air circulation and the outer air by means of single device, by providing an inner/outer air exchange damper at the I/O port of the blower while arranging an evaporator in the inner air side duct connected to the delivery portion. CONSTITUTION:The inner/outer air exchange damper 8 at the air-feed section of the blower 4 will close the inner-air feed port 1, and when the inner/outer air exchange damper 9 at the delivery section 12 will close the outer-air supply duct 6 side the outer-air will pass through the blower 4 and the evaporator 5 to be cooled and blown out through the diffuser 2 in the cabin. While when the dampers 8, 9 will close the outer-air supply duct 6 side and the outer-air suction 6 side respectively, the cooling through the inner-air circulation is performed. When the dampers 8, 9 will close the outer-air supply duct 6 side and the inner-air side duct 7 respectively, the air will flow through the air-supply port 1 in the cabin 10 to the blower 4 thus to exhaust the hot-air in the cabin quickly through the duct 6 to be used for the exhaustion of the hot-air to the outside.

Apparatus for transporting objects by means of a liquid flowing in a pipe conduit

Abstract: 1. System for moving objets (3) of a geometrically defined, uniform shape in a conduit (48) through which liquid is flowing, wherein at least one jet pump (11, 11A) with adjustable propellant pressure is connected to a charge pipe (7) serving to charge the objects (3) to be moved, characterized in that - there is arranged in the jet pump (11, 11A) a guide (12, 13, 62, 63, 80) for the objects (3) to be moved, said guide extending from the narrowing nozzle (24) of said jet pump via the cylindrical capture nozzle (25) as far as the end of the diffuser (26), terminating in a pipe conduit (48) connected to the diffuser (26), and exhibiting passages for the liquid ; - at the end of the diffuser (26) of the jet pumps (11, 11A) is arranged a water outlet connector (15, 64) for the propel ling liquid fed back to the nozzle (24, 14), and - a sub-section of the pipe conduit system exhibits a tubular jacket (41) subjected to heat from a heat source.

Fluidized-bed type sewage treating device

Abstract: PURPOSE:To speedily accomplish a steady operation at the time of starting, by providing a guide tube at such a location that the lower end of the guide tube is in proximity to or in contact with the lower end of a draft tube, while the upper end of the guide tube is placed in water above the upper surface of a stacked layer in which all carrier particles are accumulated CONSTITUTION:For starting, air is blown into the interior of an upward flow passage 3 by an air diffuser 8 to achive the linear velocity of air at the time of the steady operation As a result, a local circulating flow is generated such that the sewage in a downward flow passage 4 passes through a part beneath the lower edge of a cap 12, enters the guide tube 9 at the upper end thereof to flow downwards, flows from the lower end of the guide tube 9 into the lower end of a main tube 2 in the manner of turning back and flows upwards through the main tube 2 The carrier particles of the stacked layer 10 located at the lower part where the tubes 2, 9 are in contact with each other start to be circulated along with the local circulating flow of the sewage, and the stack starts to crumble Then, the entire part of the stacked carrier particles comes to be circulated, resulting in the steady operating condition

Ejector and method for controlling jet engine noise

Abstract: An ejector and method of reducing jet engine noise are disclosed wherein the primary combustion gas stream of the jet engine is ejected into a mixing section or zone of the ejector and into which a secondary gas stream is also injected at a velocity sufficient to create a choked or Mach 1.0 mixed flow condition, resulting in rapid mixing of the primary and secondary gas streams in the mixing zone. A diffuser is connected to the ejector downstream from the mixing zone for pulling the mixed gas stream through the mixing zone. The diffuser has an exit area greater than the area of the mixing zone. The ejector is provided with means for adjusting the area of the mixing section or zone and diffusion section to match engine operating conditions so as to create proper conditions within the mixing zone for noise suppression. Noise suppression by the method and means disclosed occurs at all frequencies with a minimal loss of thrust, and possibly a slight gain.

Hot air circulation type cooking device.

Abstract: This cooking device is provided with a hot air diffuser (4) for dividing hot air to the right and left at a partition plate (2) which partitions a heating chamber (1), and a circulating fan chamber (7) containing a circulating fan (13). It is also provided with a control wall (53) for controlling the direction the hot air diffuses in the vicinity of the diffuser (4), and a hot air bypass passage (54) connected to the wall (53), thereby defining the hot air diffusion direction to be substantially at the central direction of the chamber (1), eliminating temperature differences between the center and the periphery of the heating chamber, and in particular increasing the multiple-stage cooking effects.

Plasma cvd device

Abstract: PURPOSE:To provide a plasma CVD device which distributes gaseous flow uniformly to the spaces between electrode surfaces and to stabilize the formation of thin films by providing flow regulating devices in the inlet and outlet of the gaseous flow along the electrode surfaces in a reaction chamber. CONSTITUTION:The reaction chamber 10a of a plasma CVD device and diffusers 18a, 19a in the inlet and outlet are segments by means of flow regulating plates 11, 20. The gas introduced through an inflow pipe 18 into the diffuser 18a diffuses uniformly and is conducted uniformly between flat plate electrodes 12 and 21 which are disposed opposite to each other by passing through the holes 11a of the plate 11 until it arrives at the plate 11. Thereafter, the gas passes through the holes 20a of the plate 20. Thus the reacting gas is introduced uniformly into the reactor and the stable thin films are formed uniformly in the direction perpendicular to the gaseous flow.

Centrifugal main fuel pump having starting element

Abstract: A centrifugal main fuel pump (10') for a gas turbine engine has a housing (12') in which a centrifugal impeller (16') is mounted for rotation. The centrifugal impeller includes a disc (24') which carries starting flow impeller elements (34) which are positioned in a radially outer location on the disc and also carries main flow impeller elements (26') positioned in a radially inner location on the disc. The starting flow impeller elements discharge to a starting flow collector (38) and diffuser (44) and the main flow impeller elements discharge to a separate collector (30') and diffuser (32'). The starting flow impeller elements produce adequate fuel flow at the pressure necessary for engine lightoff while the main flow impeller elements are adapted to supply engine fuel flow demand in the normal range of operation. A check valve (46) prevents starting flow from returning to the centrifugal impeller. The check valve opens to allow the main flow impeller elements to supply fuel when their discharge pressure exceeds that of the starting flow impeller elements. The addition of a starting element to the impeller results in minimal additional parasitic power loss.

Progress toward the analysis of supersonic inlet flows

Abstract: A zonal flow analysis procedure was developed to predict the flow through the supersonic diffuser of an axisymmetric mixed compression inlet at angle-of-attack. In this analysis, the inlet flow is divided into three types of regions, each with different dominant flow phenomena. These are the inviscid supersonic core, boundary layer, and shock/boundary layer interaction flows. An appropriate analysis was selected or developed for the three-dimensional flow in each type of region. Procedures were developed to interface these analyses for the overall inlet flow analysis. This analysis was applied to an inlet operating at M = 2.58 at several angle-of-attack conditions. Comparisons are presented between computed and measured flow properties for the inlet and for the component analysis flows. Extensions of the present procedure to include the terminal shock and subsonic diffuser flows are recommended. Desirable experiments for evaluation of the inlet analysis procedure or the component analyses and to support improved modeling or extension of the inlet analysis are defined and recommended.

Diffuser with blade

Abstract: PURPOSE:To decrease the sectional area of a scroll to reduce the manufacturing cost of a casing by a method wherein the width of an outlet for the diffuser with blades is made larger than the same of an inlet therefor and the circumferential speed element of outlet flow is increased under keeping the reduction ratio of an absolute speed in the same value as before. CONSTITUTION:The diffuser 8, equipped with the blades, is constituted so that the width of the outlet thereof is larger than the same of the inlet thereof. According to this constitution, the angle of the outlet flow of the diffuser 8 is smaller than the angle of the flow in the conventional diffuser, therefore, the component of the circumferential speed at the outlet of the diffuser becomes larger than the same of the conventional diffuser. In case such flow is entered into the scroll 9a, an average speed in the scroll 9a may be made higher because the circumferential speed is high. Accordingly, the sectional area of the scroll 9a may be decreased and, as a result, the scroll 9a may be miniaturized to reduce the manufacturing cost of the scroll casing 9.

Volume control device of turbo-compressor

Abstract: PURPOSE:To improve the efficiency of a turbo-compressor by arranging a blade with an optimum shape corresponding to the flow angle of a fluid in a diffuser passage so as to eliminate a loss due to disturbances of the flow angle of the fluid. CONSTITUTION:The first blade 20 or the second blade 21 with an optimum shape corresponding to the flow angle of a fluid is automatically arranged in a diffuser passage 24 at a low load and a high load. According to this constitution, a loss due to disturbances of the flow angle of the fluid or a loss due to abrupt changes of the diffuser passage 24 width can be reduced, thereby improving the efficiency of a turbo-compressor.

Exhaust gas ducting system in a multi-cylinder internal combustion engine supercharged on the dynamic head principle

Abstract: In the case of an exhaust gas ducting system in a multiple cylinder internal combustion engine supercharged on the dynamic head principle an exhaust gas manifold is connected to the turbine of an exhaust gas turbocharger, into which manifold connecting pipes leading away from the cylinder head side exhaust gas outlets of the engine open. That area at which a connecting pipe opens into the exhaust gas manifold is designed as a short diffuser. In addition a baffle plate having approximately the form of a cone and designed to promote the flow is arranged in the mouth area of each connecting pipe as part of such a short diffuser, the cone of the plate partially projecting into the mouth area of the associated connecting pipe.

Desing of Energy-Efficient Pipe-Size Expansion

Abstract: Fluid flow is analyzed through a two‐stage conical diffuser used to reduce the velocity of pipe flow. An analytical approach is described for determining the optimum diameter at the interface between the first stage, a conical diffuser, and the second stage, an abrupt enlargement, such that, for given approach and exit diameters and for a given diffuser length, the energy loss coefficient is the lowest possible. Over a practical range of diameter and length ratios (ratios of exit diameter and diffuser length, respectively, to approach diameter), the analysis demonstrates that the optimal internal planar angle varies from 5°47′ to 17°11′ (0.101 rad–0.300 rad), and the energy loss coefficient to be applied to the approach velocity head varies from 0.01–0.25. The energy loss coefficients for the optimally designed two‐stage conical diffuser are considerably less than for a single‐stage diffuser and for an abrupt enlargement. Equations are presented showing the interrelationship among coefficients used variou...

Pressure Recovery of Collectors With Annular Curved Diffusers

Abstract: Pressure recovery is examined for axisymmetric annular curved diffusers with various values of inlet/exit area ratio. The conditions of inlet flow include three swirl angles and two values of boundary layer blockage. Then, one of the diffuser is connected to two types of collectors with different size. The discharge pressure is decreased by the collector. The cause is not deterioration of diffuser performance due to asymmetric pressure distribution but formation of a cork screw type vortex flow inside the collector. An attempt to retard the vortex motion was successful by inserting obstructions in the collector. If a large size collector is used together with proper obstructions inside the collector, pressure-rise is possible in the collector rather than pressure drop.Copyright © 1983 by ASME

A Compact Diffuser System for Annular Combustors

Abstract: Airflow tests have been conducted on an aerodynamic simulation of a combustor with pre-diffuser of compact configuration. The inlet Mach number throughout the tests was 0.35. The configuration was successful because of the attainment of a high pressure recovery, (Cp = 0.80), coupled with an exceptionally low total pressure loss (λ = 0.04). A useful analytical relationship is derived between the aerodynamic performance of combustor, compressor exit Mach number and diffuser performance.Copyright © 1983 by ASME