Showing papers on "Diffuser (thermodynamics) published in 1971"

Effects of swirling inlet flow on pressure recovery in conical diffusers

Abstract: An experimental investigation was conducted to determine the effect of swirling inlet flow on the performance and outlet flow profile of conical diffusers. Twenty four different diffusers were tested, with total divergence angles ranging from 4.0 to 31.2°, and with area ratios from 1.30 to 8.27. The effect of swirling inlet flow on diffuser performance was found to be a strong function of flow regime in the same diffuser with axial inlet flow. Swirling inlet flow did not affect performance of diffusers which were unseparated or only slightly separated with axial inlet flow. For diffusers which were moderately or badly separated for axial inlet flow, swirling inlet flow caused large performance increases based on total inlet kinetic energy. The results indicate that optimum diffuser performance for swirling inlet flow may be higher than that for axial inlet flow. However, the geometry of the optimum diffuser will differ considerably from that for axial inlet flow. New optimums are presented for the three swirl ratios investigated.

Variable diffuser centrifugal pump

Abstract: A centrifugal pump is supplied with a discharge shutter valve which provides a variable diffuser for the pump. The shutter valve includes a hollow, slotted cylinder positioned for movement into a variety of operative positions between the impeller and the diffuser vane passages. Each operative position completely closes one or more of the diffuser passages while leaving the remaining passages completely open, thereby providing a pump with high head rise over the complete operating range of the pump.

Multiple stage inflater

Abstract: A MULTIPLE STAGE INFLATER INCLUDES A CYLINDRICAL PRESSURE VESSEL HAVING AN OPENING AT ONE END RECEIVING AN IGNITER ASSEMBLY ELECTRICALLY CONNECTED WITH AN INTERIAL SWITCH OR OTHER TYPE OF INDICATING MEANS PROVIDING A SIGNAL INDICATIVE OF DEFORMATION OR THE ONSET OF DEFORMATION OF A VEHICLE BODY. THE OTHER END OF THE VESSEL INCLUDES AN OUTLET SEALED BY A FLUID PRESSURE RUPTURABLE DIAPHRAGM. THE OUTLET COMMUNICATES BY A MANIFOLD AND DIFFUSER ASSEMBLY WITH A CONVENTIONAL INFLATABLE OCCUPANT RESTRAINT CUSHION. A PROPELLANT TUBE EXTENDS PARTIALLY THROUGH THE VESSEL FROM THE IGNITER ASSEMBLY AND IS FILLED WITH SUITABLE PYROTECHNIC MATERIAL, SUCH AS BLACK POWDER. THE TUBE INCLUDES A NUMBER OF CIRCULAR OPENINGS IN THE WALL THEREOF. A PRIMARY INFLATION TUBE SURROUNDS THE PROPELLANT TUBE AND DEFINES A FIRST CHAMBER COMMUNICATING WITH THE DIAPHRAGM. THE PRIMARY INFLATION TUBE IS PROVIDED WITH A NUMBER OF CIRCULAR OPENINGS AND A REED VALVE WHICH PERMITS FLOW FROM THE FIRST CHAMBER TO A SECOND CHAMBER DEFINED BY THE PRIMARY INFLATION TUBE AND THE INTERIOR WALL OF THE VESSEL. THE SECOND CHAMBER AND THE SPACE WITHIN THE FIRST CHAMBER BETWEEN THE PROPELLANT AND PRIMARY INFLATION TUBES IS FILLED WITH AIR AT A PRESSURE LESS THAN THAT REQUIRED TO RUPTURE THE DIAPHRAGM. UPON IGNITION OF THE PYROTECHNIC MATERIAL, THE RESULTANT FLUID OR GAS FLOWS FROM THE PROPELLANT TUBE TO THE FIRST CHAMBER TO RUPTURE THE DIAPHRAGM AND INITIATE INFLATION OF THE CUSHION. THE RESULTANT FLUID ALSO FLOWS OUTWARDLY THROUGH THE PRIMARY INFLATION TUBE OPENINGS AND REED VALVE TO THE SECOND CHAMBER TO MIX WITH THE AIR THEREIN AND PROVIDE INCREASED PRESSURE FLUID. THE INCREASED PRESSURE FLUID THEN FLOWS AT A LESSER RATE BACK THROUGH THE OPENINGS IN THE PRIMARY INFLATION TUBE AND TO THE CUSHION TO CONTINUE INFLATION THEREOF. THE REED VALVE PERMITS ONE-WAY FLOW ONLY SO THAT THE INCREASED PRESSURE FLUID FLOWS AT A LESSER RATE THAN THE RESULTANT FLUID TO THE CUSHION. D R A W I N G

Gas turbine exhaust system

Abstract: An efficient exhaust system in which the fluid from a turbine is discharged into a diffusing portion. The discharged fluid then flows into an elongated transition portion and is directed at the downstream end thereof into a silencer portion by a plurality of staggered turning vanes. The discharged fluid is turned at constant velocity, and a constant area is maintained between the flow path in the transition portion and the flow path in the silencer portion. There is an additional diffuser at the downstream end of the silencer portion.

Vehicle body occupant restraint cushion system

Abstract: A vehicle body includes an instrument panel, a source of pressure fluid releasable upon the body receiving an acceleration pulse of predetermined amplitude and time, an occupant restraint cushion secured to the instrument panel within a recess thereof in a deflated folded condition, and a releasable covering over the folded cushion. A normally collapsed diffuser tube fits within the cushion and between the folded portion of the cushion and the instrument panel. The tube is connected to the pressure fluid source. The wall of the diffuser tube includes either a plurality of slits normally closed in the collapsed condition of the tube, or a plurality of openings. Upon release of the pressure fluid, the diffuser tube expands and forces the folded portion of the cushion as a unit away from the instrument panel to forcibly release the covering. The slits, which open when the tube expands, or the openings, then inflate the cushion from the pressure fluid source.

Low pressure end diffuser for axial flow elastic fluid turbines

Abstract: An improved low pressure end diffuser for axial flow elastic fluid turbines, such as steam turbines, is disclosed. A housing is provided on the outer fairing member of the diffuser, which housing defines a vented chamber. The outer fairing member is provided with openings communicating between the chamber and the annular area within the turbine casing adjacent the leading edges of the last stage turbine blades. Injection slots are formed in the outer fairing member to communicate between the chamber and the exhaust outlet downstream of the trailing edges of the last stage turbine blades. The injection slots are formed in such a manner that the fluid will flow from the chamber along a major portion of the inner surface of the outer fairing member whereby fluid boundary layer on the fairing surface will be accelerated to prevent separation of the boundary layer from the surface thereby resulting in improved diffuser performance.

Agricultural sprinkler head

Abstract: A sprinkler having a nozzle and a diffuser therefor which cooperate to provide a variable distribution of water from the sprinkler head throughout the entire circumference thereof which accomplishes almost complete uniformity of distribution of the water within the maximum and minimum limits of projection of the eater stream from the head. The nozzle is continuously driven in a circular direction and intermittently rotates simultaneously with a diffuser plate, the diffuser having diffuser vanes formed thereon which are intermittently interposed into the water stream from the nozzle to break up the pattern and the distribution thereof. The nozzle and diffuser plate travel together for one complete revolution, in fixed relationship to one another. Upon completion of each revolution, the nozzle disengages itself momentarily from the diffuser plate, and indexes itself relative to the diffuser plate a predetermined incremental distance, whereupon it re-engages and makes another complete revolution, so that the nozzle is constantly changing its relationship with respect to the diffuser plate, and the water dispersing or diffusing vanes provided thereon. The relative indexing of the nozzle and the diffuser plate is accomplished by a gear formed on the nozzle, and a pinion carried by the diffuser plate, which pinion engages the gear on the nozzle, and also engages each complete revolution, a stationary pin which is the equivalent of one tooth of an internal gear. When the pinion engages the pin, it causes the aforementioned disengagement of the diffuser and nozzle and indexing of the nozzle to the next diffuser station or vane.

Inflatable occupant restraint system

Abstract: A pressure vessel containing compressed fluid has the outlet thereof sealed by a rupturable plug. The outlet communicates with a manifold which in turn communicates with one end of an elongated cylindrical diffuser. The diffuser includes longitudinal rows of partial circumferential slots. Each row communicates the diffuser with the interior of a respective inflatable occupant restraint cushion. A cylinder is supported within the manifold by radial ribs thereof engaging the interior wall of the manifold. A conical headed piston is slidable within the cylinder and the space between the piston and a closed end wall of the cylinder is filled with viscous fluid. An aperture in the closed end wall of the cylinder receives a pintle secured to the piston. The conical head of the piston is located in predetermined relationship to a fixed area orifice at the outlet of the pressure vessel. A tubular diffuser screen is inserted within the diffuser and covers the slots to the cushions. One end of the screen opens to the manifold and the other end of the screen is closed by a plug of resilient material.

Surge control for fluid compressors

Abstract: A control means for preventing surging under changing or low flow conditions in a fluid compressor such as an air compressor which includes a rotor and diffuser and at least two stages of compression is disclosed. Compressed air from the n+1 stage of the compressor is injected into the diffuser of the nth or lower stage of the compressor through a collection chamber which is disposed about the diffuser.

Viscous slipstream flow downstream of a centerline Mach reflection

Abstract: Viscous slipstream flow downstream of triple shock wave intersection in supersonic diffuser air flow, using Pitot and static pressure probe measurements

Recirculating annular slot fuel/air carbureting system for gas turbine combustors

Abstract: A combustion system for a gas turbine engine is equipped with a fuel carbureting device which delivers a uniform fuel/air mixture to the primary combustion zone through a continuous annular exit slot. Fuel and air are provided as a continuous tangential flow to an annular premixing chamber, which is configured so as to provide a throat, a diffuser zone, and the annular exit slot. Radial swirl vanes are positioned within the premixing chamber to turn the fuel/air mixture axially, and counterswirl vanes surround the exit slot to provide additional primary combustion air to rapidly mix with the fuel/air mixture and to provide flame stabilization regions around the entire annular combustion chamber. Recirculation of the hot gases in the primary combustion zone is achieved by providing a diffuser zone upstream of the exit slot with a bluff body splitter for radially turning the fuel/air mixture.

Pipe diffuser with auxiliary bleed system

Abstract: The disclosure illustrates a ''''pipe'''' diffuser having basic flow passages sized to handle the output requirements of a centrifugal compressor without a bleed requirement. The diffuser has a series of auxiliary bleed passages intersecting the inlet portions of the pipe diffuser passages. The bleed passages are sized to handle a supplementary bleed flow requirement when needed.

Pipe diffuser with aerodynamically variable throat area

Abstract: A ''''pipe'''' diffuser comprises an annular housing surrounding a centrifugal impeller and has primary diffuser passages intersecting with one another to form scallop-shaped entrance edges. A series of ports are provided in the throat region of the diffuser passages to momentarily inject pressurized diffuser exit air to aerodynamically vary the throat flow characteristics and prevent surge during operation of the stage above its normal surge line.

A method of flow stabilisation with high pressure recovery in short, conical diffusers

Abstract: The problem of obtaining proper flow spreading together13; with useful pressure recovery across rapidly expanding13; diffusers is of considerable practical importance, Many13; different approaches to this end have, been reported in13; literature, e.g. vortex generators, screens or bailies, surface roughness, corrugations, etc., apart from the use of direct boundary-layer control. These methods have the common13; aim of preventing separation from the walls of the diffuser. 13; With increasing expansion angle and area-ratio, however, the effectiveness of these methods either breaks down or is obtained at a high cost of pressure recovery.

Measurement of the Intermittency Factor in Diffuser-Flow

Abstract: The intermittency factor in a thick axisymmetric boundary layer with positive pressure gradient (diffuser-flow) was evaluated with hot-wire anemometers and a multi-channel analyzer. The probability...

Calibration of the Langley Mach 20 high Reynolds number helium tunnel including diffuser measurements

Abstract: Flow characteristics including diffuser measurements of Langley Mach 20 high Reynolds number helium tunnel

Pitless well adapter

Abstract: In the case of a jet pump water system two round holes are cut in the well casing below the frostline A casing fitting is attached fluid-tight to the casing around the two holes The casing fitting has pressure and suction cylindrical recesses located beyond the inner wall of the casing, coaxial with the casing holes Pressure and suction pipes are connected to the pressure and suction recesses and extend horizontally below the frostline into a dwelling to a pump and a water delivery conduit A drop fitting has pressure and suction conduit necks which fit fluid-tight into the pressure and suction recesses An inner assembly has drop and jet diffuser fittings at the top and bottom respectively of pressure and suction drop pipes The inner assembly is lowered into the well with the pressure and suction conduit necks pointed in the direction of the conduit recesses When the necks reach approximate alignment with the recesses an actuator automatically inserts the necks into the recesses and rigidly locks them in Thus, the pressure and suction pipes and drop pipes are coupled fluid-tight and the inner assembly is rigidly supported To remove the inner assembly, it is first additionally supported with a hoist, then the conduit necks are withdrawn from the recesses by a manual lift on a control cable (which reverses the actuator) and the inner assembly is lifted out with the hoist The casing fitting and the drop fitting, which includes the actuator, comprise the invented pitless well adapter

Inlet structure for turbo machine

Abstract: The inlet nozzle blades of a fluid turbo machine are mounted radially in the exhaust diffuser tube encircling the nose piece and the turbine wheel The inner ends of the nozzle blades engage the nose piece and are held against the same by a clamping band encircling the outer ends of the blades The clamping band will stretch to accommodate radial growth of the blades by expansion during operating temperatures An inlet passage member is attached to the machine casing and serves to detachably clamp the exhaust diffuser to the casing and also the nose piece in the diffuser Provision is made for radial expansion of the nose piece relative to the diffuser

Air conditioner diffuser

Abstract: An air conditioner diffuser having a plurality of telescopic tiers or sleeves with apertures surrounding the peripheries thereof for permitting the passage of conditioned air therethrough. The sleeves not only are capable of being moved in a vertical direction but are provided with means for movement in any horizontal direction so as to adjustably control the volume and flow of conditioned air therethrough in any desired direction.

Effect of diffusers, shrouds, and mass injection on the starting and operating characteristics of a Mach 5 free jet tunnel

Abstract: Diffuser, shroud, and mass injection effects on starting and operating characteristics of Mach 5 free jet tunnel at low pressure ratios

Gun blast stripper and diffuser

Abstract: An apparatus for diffusing and directing the energy from a gun blast from aircraft mounted guns including a stripper attached to each said gun, said stripper having a plurality of openings for directing energy from a gun blast in a downward direction, a curved acceleration ramp positioned forward of said guns, and one or more cascades for directing energy downwardly.

Investigation Concerning the Fluid Flow in the Mixed-Flow Diffuser

Abstract: Velocity profile measurements were performed on the flow in a mixed-flow diffuser with walls having equal cone angles. The aim of the present study is to understand the flow behavior and the relation between the flow patterns and the diffuser losses. The boundary layer flow accompanied by separation on the inner wall and the velocity normal to the diffuser walls were measured in detail to examine the three-dimensional flow behavior in the mixed-flow diffuser. Comparing with the radial diffuser, the mixed-flow diffuser had a more complicated flow mechanism as it had the pressure gradients of transverse and normal directions.Copyright © 1971 by ASME

Filter bag backflushing device

Abstract: The device relates to external bag filters, into which a backflushing stream is introduced intermittently via the gas outlet. Flush gas is introduced via a nozzle ring into a tube with a diffuser section to produce swirl flow over the full section of the filter bag.

Gas flow diffuser

Abstract: For large-scale gas chromatography separation apparatus, a diffusing structure in between the inlet line and the packed column. There are a plurality of funnel-shaped coaxial baffles for spreading the gas flow into the column to reduce channeling in the column.

Effect of Swirl on Conical Diffuser Performance

Abstract: : The report deals with an experimental investigation of the effect of swirl on conical diffuser performance. Data on the gross performance of conical diffusers are reported. The effect of swirl on the separation phenomena in a conical diffuser has been studied. Success has been achieved in avoiding the separation completely through swirl in conical diffusers of a divergence angle as large as 35 degrees. An optimum swirl angle has been found for each diffuser. Turbulence level measurements are taken and they indicate that turbulence is not a dominant factor in eliminating separation. (Author)

Diffuser for centrifugal compressor

Abstract: The disclosure illustrates a diffuser of the ''''pipe diffuser'''' type in which the intersecting inlet flow passages are formed by the volume swept by a cylinder displaced from a first position in which its longitudinal axis is tangent to a reference circle to a second position. This enables the diffuser to handle a given flow rate with a minimum number of passages and provide increased flow range for the stage.

Jet Flap Diffuser: A New Thrust Amplifying Device

Abstract: A jet sheet is proposed as an alternative to a rigid diffuser for a momentum propulsor. This appears attractive technically since the diffuser shape can be tailored by modulating jet momentum and angle and can be switched off in forward flight, its main function being to increase thrust-power ratio at static speeds. Theoretical global analysis for a steady inviscid incompressible flow predicts impressive thrust amplifications, showing effects of blowing coefficient, angle and jet thickness. Taking into account the energy required to feed the jet sheet, the propulsor thrust/power ratio is generally increased. The device can be applied to ducted fans, jet engines and seems particularly attractive for ejector thrust systems. To determine flow details, a linearized solution of the planar problem is given. A mapping transforms it into a half-plane boundary value problem of the Riemann-Hilbert-Poincare type. It is solved by combining Hilbert Transforms, asymptotic expansion, and a digital computer program.

The influence of inlet velocity distribution on the flow through a plane curved diffuser

Abstract: The influence of inlet velocity distribution on the flow through a plane curved diffuser " (1971).

Study on Flow Inside Diffusers for Centrifugal Turbomachines : Report 1, Diffusers Curved in Logarithmic Spiral Form under Uniform Inlet Flow

Abstract: Flow inside a diffuser consisting of two curved walls of logarithmic spiral and two parallel flat walls was investigated Secondary flows and boundary layer growth were measured in detail A method of calculation for boundary layers and diffuser performance was given (1) A pair of secondary flow vortices due to flow curvature is recognized They are intense on the convex wall and very weak on the concave wall (2) Secondary flows build up typical skewed boundary layers on the side walls Their velocity profiles are approximately expressed by the formerly known formula for skewed boundary layers of non-decelerating flows (3) On the side flat wall the boundary layer growth is little, while it is very rapid on the convex wall It is related with secondary flow conditions (4) With consideration of these flow phenomena, a method of numerical calculation was given using orthogonal curvilinear coordinates Effects of inlet boundary layer thickness and Reynolds number were also studied