Showing papers on "Diffuser (thermodynamics) published in 1980"

Lighter than air wind energy conversion system utilizing an external radial disk diffuser

Abstract: A lighter-than-air (LTA) wind energy conversion system (WECS) wherein the gas-filled LTA envelope carries a main rotor and electrical generator to take advantage of high wind speeds available at high altitudes. The LTA envelope is tethered to a ground based mooring system designed to provide self-orientation for the LTA envelope. In a preferred embodiment, heavy mechanical transmissions are eliminated by providing a radial disk diffuser within the LTA envelope coupled through a drive shaft to a wind-driven external rotor. Rotation of the rotor-diffuser drives an induction turbine positioned within the gas inlet to the diffuser, the lifting gas for the envelope also serving as the working fluid for the turbine. The output of the induction turbine is coupled to an electrical generator whose output is, in turn, transmitted to the ground via the tethering system.

Gas to liquid diffuser

Abstract: A static diffuser for use within the water tank of an ozonator system. The diffuser comprises a depending water pipe into which water is fed under pressure by an external pump. The lower end of the pipe flares outward and has an internal fixed cone which combines with the flared end of the pipe to provide an annular laterally directed water discharge. The annular discharge includes angularly directed vanes to enhance the water discharge and assist in forming a high velocity outwardly directed circular sheet of water. The pipe is surrounded, in spaced relation, by a shroud through which the ozone is introduced. The shroud is provided with an annular slot outward of the pipe discharge, the shape of the shroud at the slot forming a modified 360° circular venturi whereby the discharging high velocity sheet of water creates a negative pressure drawing the ozone therewith into the surrounding body of water for a ozonation thereof.

Microwave fluid heating system

Abstract: A microwave heating system utilizing a magnetron for generating the microwaves. The microwaves are sent to a diffuser which spreads the microwaves in an upper chamber of a housing from where they can bounce off the metal walls of the upper chamber and pass through a clear plastic material into a lower chamber. A fluid passes through a circuitous path in the lower chamber and is heated by means of the microwaves.

Method and apparatus for the control of shielding gases used in power laser processes

Abstract: In order to remove the plasma cushion and loose metal material created by the action of the laser on a metal workpiece, a shielding gas jet is directed from a nozzle across the workpiece surface through the zone of action of the laser beam. The shielding gas rather than being allowed to go to waste is collected, purified of the metal material contained therein and fed back to the nozzle. This recirculation of the shielding gas is effected in ducting which incorporates in succession between the gas-collecting input end and the nozzle, a diffuser to slow the gas, a cooling chamber, a separator for removing metal particles condensed out of the stream, a pump, a filter and further cooling means.

Effect of Swirl on Pressure Recovery in Annular Diffusers

Abstract: Annular diffusers are likely to operate with varying amounts of swirl at the inlet. The work described in this paper is concerned mainly with an experimental investigation of subsonic turbulent swirling flows through annular diffusers having diverging hub and casing boundaries. The test facility was designed SO as to peImit different levels of inlet swirl. The static pressure distributions and the axial and tangential velocity profiles were measured with the help of a three-hole cobra probe suitably mounted at different cross sections along the diffuser length. The diffuser performance parameters such as static-pressure recovery, effectiveness, and the total pressure loss coefficient were then computed from the experimental observations. The behaviour of these parameters has been discussed to establish the effect of swirl. The presence of inlet swirl was found to increase the overall static-pressure recovery. A substantial increase in the pressure recovery occurred over the initial stages of diffusion and...

Diffuser of centrifugal compressor

Abstract: A centrifugal fluid compressor including a rotatable fluid impeller and a fluid diffuser positioned coaxially around the impeller and comprising a plurality of diffuser vanes each arranged in such a manner that the angular position of the vane with respect to the center axis of the impeller and the distance between the outer peripheral end of the impeller and the leading end of the vane are variable independently of each other.

Process and apparatus for producing nitrogen and oxygen

Abstract: A process for producing nitrogen and oxygen from a precompressed and cooled air, comprising compression of air to a pressure of from 0.3 to 0.6 MPa, cooling the compressed air to a saturated state with a partial liquefaction at a temperature of from 90° to 100° K. The cooled air with a partial content of the liquid is supplied to separation into at least one vortex tube. An apparatus for carrying said process comprises a compressor (1) and heat-exchangers (2) positioned along the path of movement of the compressed air, which heat-exchangers have a high-pressure cavity and a low-pressure cavity, and a vortex tube (4) having, at one end thereof, an inlet nozzle (5) and a diaphragm (6) for discharging nitrogen and, at the other end thereof, a diffuser (7) for discharging oxygen. The inlet nozzle (5) of the vortex tube (4) is connected with the high-pressure cavity of the heat-exchanger (2), while the diaphragm (6) of the vortex pipe (4) is connected with the low-pressure cavity of the heat-exchanger (2).

High velocity exhaust diffuser and water baffle

Abstract: A diffuser and baffle device prevents sea water intrusion or ingestion into marine gas turbine engine exhaust system without significantly increasing exhaust back pressure. Inboard and outboard rows of vertical turning vanes are separated by a gap and effect successive bends of the exhaust flow in opposite directions while affording an increase in cross-sectional area. The outboard vanes are slotted at their inboard edge portions, and the inboard vanes are provided with hook-shaped projections defining grooves, whereby water driven into the device is arrested and drained overboard.

Applicability of the isotropic vorticity theory to an adverse pressure gradient flow

Abstract: An examination of the isotropic vorticity theory was made in an adverse pressure gradient flow based on experimental data obtained in a conical diffuser having a total divergence angle of 8° and an area ratio of 4:1 with fully-developed pipe flow at entry. The results showed that the rates and the ratio of production and dissipation of the turbulent vorticity were constant in the core region of the diffuser but increase significantly in the wall layer. The overall vorticity balance was essentially the same at all axial stations. The analysis of Batchelor & Townsend (1947) for isotropic vorticity was found to be valid in the core region of the diffuser for an order-of-magnitude higher Rλ (200 [les ] Rλ 600) than in grid turbulence. The magnitude of the skewness of ∂u1/∂t was constant in the core region and comparable to that for grid turbulence. Also, this region of constant skewness extended over a larger portion of the flow cross-section compared to pipe flow. On the basis of these results, it was concluded that assumptions of isotropy in the fine structure are valid in the core region of the diffuser.

Fire hydrant diffuser

Abstract: A fire hydrant diffuser comprising a flared housing rectangular in cross section having disposed therein a pair of water diffusing members in opposed relation angled to form a V-configuration and having a stepped mesh structure positioned relative to the direction of flow of water to present narrow obstructing slits for the passage of the water.

Model Studies for a Wave Riding Facility

Abstract: Results of a model study for producing a stationary, oblique continuously breaking wave in a recirculating flume are reported. The wave is produced by placing a suitably shaped obstacle in the path of the flow issuing from a sluice gate. Attached to the downstream end of the obstacle is a turning vane which enables the flow to execute a 180 turn with minimum energy losses while remaining supercritical. The type of wave produced in the facility is demonstrated by a typical wave surface contour plot. Detailed pilot surveys of the flow are used to identify the main sources of power losses. These occur in the vicinity of the drive propellers and in the diffuser downstream. The studies indicate that it should be possible to produce a wave 1 m high in the facility which is presently under construction.

Variable vane seal

Abstract: A diffuser for a centrifugal compressor has an annular array of vanes which is movable to vary the configuration of the diffusing passages between the vanes. Each vane includes suction and pressure surfaces joined at an inlet apex and divergent therefrom to form a wedge-shaped control surface between fixed, spaced parallel side walls of the diffuser and pivoted about the apex for varying flow area through the diffuser. Each vane has an elastomeric inner portion which is selectively inflatable to expand to either side of said wedge-shaped control surface to sealingly engage the spaced parallel side walls to seal against gas flow between the pressure surface and the suction surface on each of the vanes.

Method and device of distribution control for high pressure powder

Abstract: PURPOSE: To smoothly transport gas by connecting several pairs of gas supply pipes and exhaust pipes for gas transportation to a storage tank and supply an auxiliary gas on the basis of the detection of a flow rate of powder in the exhaust pipes. CONSTITUTION: Plural supply pipes 6a and the same quantity distribution exhaust pipes 7a for gas transportation are connected to a powder storage tank 1 disposed in series to a hopper 5. The pipes 6a, 7a are made up with a relation between a nozzle and a diffuser of an injection feeder. A flow rate of a gas transported through the pipes 6a is detected by a flow rate detector 15 and its detected output is fed to a flow regulator 18 and a regulation gauge 32 via a transfer unit 17 to control valves 16, 24. Supplied gas through the pipes 6a or a pipe 22 is controlled on the basis of a measurement of a pressure difference detector 30, thereby performing accurate constant flow control. COPYRIGHT: (C)1982,JPO&Japio

Arrangement for sucking-off gases

Abstract: Arrangement for sucking-off gases, creating by means of water supplied to an annular nozzle surrounding the outlet of a gas conduit and forming a first hydraulic pump with a vortex, thereby mixing the gas and water thoroughly and sucking off the mixture by a second annular water nozzle into an ejector or second pump extending into a diffuser which terminates below the level of water in a vessel, where separation of the gas and water takes place.

An analytical and experimental study of a short s-shaped subsonic diffuser of a supersonic inlet

Abstract: A subscale HiMAT forebody and inlet was investigated over a range of Mach numbers to 1.4. The inlet exhibited a transitory separation within the diffuser but steady state data indicated reattachment at the diffuser exit. A finite difference procedure for turbulent compressible flow in axisymmetric ducts was used to successfully model the HiMAT duct flow. The analysis technique was further used to estimate the initiation of separation and delineate the steady and unsteady flow regimes in similar S-shaped ducts.

Modeling pressure oscillations in Ramjets

Abstract: Pressure oscillations in ramjet engines are approximated as one-dimensional motions and treated within linear acoustics. The exhaust nozzle is represented by the admittance function for a short choked nozzle. New results have been obtained for the quasi-steady response of a normal shock wave in the diffuser. Acoustic fields in the inlet region and in the combustion chamber are matched to provide an analytical expression of the criterion for linear stability. Combustion processes are accommodated but not treated in detail. As examples, data are discussed for two liquid-fueled engines, one having axial dump and one having side dumps.

Small gas turbofan engine with regenerating diffuser

Abstract: A mixed flow, high bypass, gas turbofan engine that is small and compact, and that develops a thrust in the range of approximately 200-300 pounds. The engine has an axial length of approximately 18 inches, an air inlet of approximately 10 inches in diameter, and an exhaust nozzle of approximately 6 inches in diameter. To reduce engine length high pressure compressor diameter, a high pressure compressor is positioned in a location that is displaced from and is preferably parallel to the engine axis (i.e., centerline), a burner (i.e., combustion chamber) is similarly positioned on the other side of the engine axis, only one turbine is used, and a unique flow path also is used. In addition, a heat exchanger of the regenerative type which includes a plurality of pipe diffusers is used, and it is positioned in the hot exhaust flow of the single turbine to pre-heat the compressor air prior to entry into the burner. Further, a gear shift may be used with the compressor to give better part-power performance. The small size, the thrust capability, and the good fuel consumption during part-power operation, make this engine ideal for use in air-launched cruise missiles.

Centrifugal compressor withhtwoosuctionnport

Abstract: PURPOSE:To spin air efficiently in the circumferential and axial direction of a diffuser at even velocity by displacing left and right impeller blades by half a pitch which are crossed with each other to make one round outlet. CONSTITUTION:Each pair of impeller blades 1a, 1b on the left and right sides of a hub 3 is placed as shown which are displaced by half a pitch P/2. These left and right impeller blades displaced are crossed with each other on the side of a diffuser 5. The end of a hub 3 near the blade chip is cut off 7 due to cross of the both blades 1a, 1b. This constitution of the impeller blades 1a, 1b removes jet/ wake so that air can be spinned at even velocity in the circumferential direction of the diffuser.

Tankkinside type vertical shaft suction diffuser pump

Abstract: PURPOSE:To reduce size and weight and also provide rated specification points over a wide range as well as providing a stable characteristic by adopting a diffuser type casing for the tank-inside type vertical slurry pump. CONSTITUTION:A diffuser casing 3, the inner wall of which is provided with diffusers 3A uniformly spaced apart in the radial direction, is secured to the lower end of a pump-up tube 4 surrounding a pump shaft 5 of a vertical slurry pump, and a suction side casing 1 having a bellmouth 1B is provided at the suction side end. In the inside of the pump of the above construction, the pump shaft 5 is provided at its lower end with an open side impeller 2 capable of movement along it. With this construction, the installation area and weight of the pump can be reduced compared to the conventional tank-inside spiral vortex suction pump, so that it is possible to render homogenious the withdrawn slurry and prevent generation of vibrations and blocking of passage.

Investigation of the Starting Process of a Supersonic Wind Tunnel

Abstract: The starting process of a supersonic wind tunnel with a diffuser with contraction has been studied in detail by schlieren optical observations and pressure measurements. As the result, it has been shown that the wind tunnel starts when the flow is even sonic but not choked at the second throat. Based on this fact, the flow in the starting process has been classified into three patterns according to the area ratio of the second throat to the test section. Furthermore, the differences between the theoretical values and the experimental results of the starting pressure ratio and the minimum starting area at the second throat have been well explained, taking into consideration the fact that a normal shock wave assumed in the previous one-dimensional theory becomes a pseudo-shock wave due to the interaction with the wall boundary layer.

Near Field Mixing of Staged Diffuser

Abstract: A two-dimensional theory that models a staged diffuser as a continuous line source of mass, heat, and momentum has been formulated and solved. The model assumes the major dilution mechanism is due to side entrainment, and involves the use of only an entrainment coefficient obtained from classical jet literature. Constant induced velocities and excess temperatures are predicted. Solution properties are compared with that of a turbulent free jet, and the theoretical predictions are validated against existing experimental data. In the case of a diffuser discharging on a sloping bottom, the theory also suggests an optimal distribution of the momentum and heat load to take advantage of the increasing depth in the offshore direction.

Air control apparatus

Abstract: An improved variable volume air controller for use in conjunction with a conditioned air distribution system is disclosed which comprises an insulated lined housing having an inlet, an outlet, and a control assembly operative to vary the volume of air flowing therethrough. An air flow diffuser is also provided being positioned in overlying relationship to the inlet opening which operates to substantially improve air flow distribution over the cross sectional area of the housing whereby the control assembly may operate to provide improved relatively noise-free modulation of air flow. Additionally, a stop assembly is provided which cooperates with a portion of the control assembly to limit movement thereof beyond a true full open position as well as to inhibit air flow induced vibration thereof when the control assembly is in a full open position.

Jet-diffuser Ejector - Attached Nozzle Design

Abstract: Attached primary nozzles were developed to replace the detached nozzles of jet-diffuser ejectors. Slotted primary nozzles located at the inlet lip and injecting fluid normal to the thrust axis, and rotating the fluid into the thrust direction using the Coanda Effect were investigated. Experiments indicated excessive skin friction or momentum cancellation due to impingement of opposing jets resulted in performance degradation. This indicated a desirability for location and orientation of the injection point at positions removed from the immediate vicinity of the inlet surface, and at an acute angle with respect to the thrust axis. Various nozzle designs were tested over a range of positions and orientations. The problems of aircraft integration of the ejector, and internal and external nozzle losses were also considered and a geometry for the attached nozzles was selected. The effect of leaks, protrusions, and asymmetries in the ejector surfaces was examined. The results indicated a relative insensitivity to all surface irregularities, except for large protrusions at the throat of the ejector.

Jet pump for nuclear furnace

Abstract: PURPOSE: To prevent the damage of a structure inside a furnace by providing projections on the periphery of the lower part of a mixer and fitting the projections into the slots formed on the inner periphery of the upper part of a diffuser and connecting the mixer and the diffuser in such a manner that they may not be pulled out and then by preventing the dispersion of integrated weld. CONSTITUTION: Two projections 28 are formed on the outer periphery of the lower part of a mixer 15. The two projections 28 are so placed as to face each other oppositely apart from the central axis of the mixer of cylindrical shape. On the inner periphery of the upper part of a diffuser 16 are formed slots 29 into which the projections 28 can be fitted. On the upper part of the slots 29 are provided notches which allow the projections to be inserted. The lower part of the mixer 15 is set to the upper part of the diffuser so that the projections 28 may be placed in the notches 30. And then, the mixer 15 is lowered and turned, allowing the projections 28 to be fitted into the slots 29. Both the projections and slots are engaged in an integrated block. This construction serves to maintain the state of connection between the mixer 15 and the diffuser 16, even if elbows 13 are separated from a transition piece 12. Therefore, the structures inside the furnace can not be dispersed and the damage can be prevented. COPYRIGHT: (C)1981,JPO&Japio

Measurement of Flow Velocity in the Vaneless Diffuser of a High-speed Centrifugal Compressor Using a Laser Doppler Anemometer

Abstract: A laser Doppler anemometer using the photon correlation technique has been used to measure the radial and tangential flow in the vaneless diffuser of a high-speed centrifugal compressor. Measurements have been made at several points in the diffuser region to define the blade-to-blade velocity profile. The compressor was fitted with a 101·6 mm diameter back-swept impeller. Results are shown for two blade tip speeds, 335 and 338 m s-1, for which the blade passing frequencies are 16·2 and 19·4 kHz respectively. Velocity profiles show that the flow is severely distorted in the blade-to-blade and hub-to-shroud planes. Such results raise questions about the one-dimensional flow analysis commonly used to design the vaned diffusers of centrifugal compressors.

Fire suppressant impact diffuser

Abstract: A bullet-shaped deflector located at the exit opening of a liquid nozzle nted on a fire-suppressant storage bottle stationed within a military vehicle. The deflector acts as an obstruction to reduce liquid jet issuing from the nozzle. The system is designed for liquid pressure of 750 p.s.i. and nozzle openings of about 11/4 inch diameter. The bullet-shaped deflector may have a diameter of about 5/16 inch and an axial length of about 1 inch.

Reservoirrhoused pump equipped with agitator and mixer

Abstract: PURPOSE:To smooth conveyance of liquid mixed with solids owing to increase in pulverization of masses, circulation of liquid, and suction pressure by providing a mechanism comprising an axial-flow propeller and a drum-type casing at the front side of a suction port. CONSTITUTION:An axial-flow propeller 4 is fitted to the front end of a pump axle 3 which extends in upstream direction on suction side by penetrating through a main pump impeller 1 and a suction port 2A of its pump casing 2, further, the axial-flow propeller 4 is positioned in an upright trunk part 6A of a drym type casing 6 attached to a lateral part 5A in the axial direction of a diffuser 5 allocated in bursting-star pattern at the outer bulkhead surfaces on the suction side of the casing 2. This propeller 4 is made into a shape and intensity compatible to pulverize big solid masses, solid floating distribution is equalized by forming to effectively discharge and circulate liquid which has a diffuser 6 discharged from the propeller 4.