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Showing papers on "Axial compressor published in 1978"




Journal ArticleDOI
R.E. Longhouse1
TL;DR: In this article, a low-tip speed axial flow fan with eight equally spaced blades was tested in both free field and reverberant field environments and the fan backpressure and speed were varied during the tests.

101 citations


Journal ArticleDOI
TL;DR: In this article, detailed flow measurements obtained by a new measuring technique are presented for the flow in a stalled axial-flow compressor, based on the observation that the fluid must cross from one side of the cell to the other in order to preserve continuity in the tangential direction.
Abstract: Detailed flow measurements obtained by a new measuring technique are presented for the flow in a stalled axial-flow compressor. Results were obtained from a wide range of compressor builds, including multi-stage and single-stage configurations of various design flow rates and degrees of reaction. Instantaneous recordings of absolute velocity, flow direction and total and static pressures have been included for both full-span and part-span stall.With the aid of these results, it has been shown that the conventional model of the flow in a stall cell is erroneous. An alternative model is proposed, based on the observation that the fluid must cross from one side of the cell to the other in order to preserve continuity in the tangential direction. An investigation of the experimental results also reveals the finer details of the flow in the cell and shows how these details are related to the design flow rate of the compressor. The influence of these cell details on the power absorbed by a stalled compressor ar...

90 citations


Journal ArticleDOI
TL;DR: In this paper, heat transfer coefficients were measured for the flow in the annular space between an inner rotating cylinder and an outer stationary one, with superimposed axial flow, at three different Prandtl numbers 2.5, 4.5 and 6.5.

69 citations


Patent
22 Aug 1978
TL;DR: In this article, a turbine or like rotary machine of the kind in which a fluid, either a liquid or gas, is arranged to act on a plurality of generally radially extending rotor blades, has each rotor blade fixed in position relative to the rotor hub and is substantially symmetrical about a plane perpendicular to rotor axis, the blades having surfaces of generally aerofoil shape and being mounted with their leading edges facing in the same circumferential direction.
Abstract: A turbine or like rotary machine of the kind in which a fluid, either a liquid or gas, is arranged to act on a plurality of generally radially extending rotor blades, has each rotor blade fixed in position relative to the rotor hub and is substantially symmetrical about a plane perpendicular to the rotor axis, the blades having surfaces which are of generally aerofoil shape and being mounted with their leading edges facing in the same circumferential direction. The rotor of such a turbine can be driven by a generally axial flow of fluid, the direction of rotation being unchanged when the direction of flow of the fluid is reversed, so that it can be used to advantage in an oscillating or periodically reversing fluid flow. Such a flow may be provided or produced for example, by naturally occurring movement of air or water.

46 citations


01 Nov 1978
TL;DR: In this paper, the overall and blade-element performance of a low-aspect-ratio transonic compressor stage is presented over the stable operating flow range at 70, 90, and 100 percent design speeds.
Abstract: The overall and blade-element performance of a low-aspect-ratio transonic compressor stage is presented over the stable operating flow range at 70, 90, and 100 percent design speeds. At design speed the rotor and stage achieved peak efficiencies of 0.872 and 0.845 at pressure ratios of 1.875 and 1.842, respectively. The stage stall margin at design speed was 21.8 percent.

44 citations


Patent
22 Aug 1978
TL;DR: In this paper, a surge control system for a centrifugal compressor having a recycle line between the discharge and suction, modulates flow in the line in accordance with molecular weight and temperature of the gas being compressed, pressure drop across the inlet orifice, and power input to the compressor.
Abstract: A surge control system for a centrifugal compressor having a recycle line between the discharge and suction, modulates flow in the line in accordance with molecular weight and temperature of the gas being compressed, pressure drop across the inlet orifice, and pressure drop across and power input to the compressor. The system is based on the standard relation that the product of the gas constant times the pressure drop across the inlet orifice divided by the suction temperature equals the pressure drop across the compressor.

32 citations



Journal ArticleDOI
TL;DR: In this article, the effects of the fan rotational frequency and blade thickness at the trailing edge are compared with the theoretical results and the agreement of the theoretical and experimental results is generally quite satisfactory.

30 citations


Journal ArticleDOI
TL;DR: In this article, the passage of distorted flow through an annular axial compressor rotor or stator is analyzed in the actuator disk limit, and the resulting analysis yields an overall description of the blade row performance in the presence of inlet flow defects.
Abstract: The passage of distorted flow through an annular axial compressor rotor or stator is analyzed in the actuator disk limit. In such a description the flow is steady in absolute coordinates. The resulting analysis yields an overall description of the blade row performance in the presence of inlet flow defects. The present (actuator-disk) analysis is compared successfully with Dunham’s earlier three-dimensional analysis as well as with recent experimental data. In addition, comparison with a recent theory by Greitzer, employing an alternative approach, is made. The analysis shows that at least two important distinct types of vorticity arise, the one being directly analogous to the trailing vorticity (shed circulation) of classical wing theory, and the second being analogous to the vorticity occurring in “secondary flow” theory. The latter arises directly as a result of inlet distortion. The resulting varying flow angles produce spanwise variation in blade loading, and consequent trailing vorticity (Beltrami Flow). The two types of vorticity are therefore interrelated. The static pressure field is also affected by this coupling in agreement with experiment. This problem provided a striking example for which three-dimensional and two-dimensional analyses disagree qualitatively. The vorticity as viewed in coordinates fixed in the rotor is discussed in the Addendum.

Journal ArticleDOI
TL;DR: In this article, an experimental investigation into the way in which compressor exit conditions influence the performance of two optimum combustor-dump diffusers was conducted. But the results were limited to a single diffuser with fully developed flow at inlet.
Abstract: Results are presented of an experimental investigation into the way in which compressor exit conditions influence the performance of two optimum combustor-dump diffusers. In an optimum system nearly all of the pressure rise occurs in a relatively long prediffuser which is designed to produce a symmetrical outlet velocity profile at the design flow split. One diffuser was tested downstream of a seven-stage axial flow compressor and, for comparative purposes, retested with fully developed flow at inlet. The second diffuser was tested downstream of an annular tandem cascade which could be sited at a number of positions relative to diffuser inlet. The overall performance, measured when the wakes from the outlet guide vanes had decayed considerably, was the same as that achieved with fully developed inflow.

Proceedings ArticleDOI
H. Mishina1, I. Gyobu1
09 Apr 1978
TL;DR: An experimental investigation concerning the optimum relative velocity distribution within impellers, the optimum diffusion ratio of vaned diffusers and the optimum circumferential area distribution, sectional shape of scrolls was carried out using high specific speed shrouded impellers with backward leaning blades as discussed by the authors.
Abstract: An experimental investigation concerning the optimum relative velocity distribution within impellers, the optimum diffusion ratio of vaned diffusers and the optimum circumferential area distribution, sectional shape of scrolls was carried out using high specific speed shrouded impellers with backward leaning blades. A performance design procedure based on loss analysis and quasi-three-dimensional flow analysis was also developed and modified by introducing experimental results. The design procedure was applied to a 7900-kw four-stage air compressor to demonstrate the usefulness. Field test results of the complete machine showed that the maximum isothermal efficiency was 75 percent with the pressure ratio of 5.96 and the flow rate of 29.3 m3/s.Copyright © 1978 by ASME



Patent
20 Dec 1978
TL;DR: A gas turbine plant including a compressor section and a turbine section housed within a multipart casing with the shafts of each section co-axial, the compressor section including a double-sided low-pressure radial compressor, a high pressure radial compressor and an intercooler, while the turbine stage includes a first stage axial turbine on the same shaft as the compressor and at least an additional turbine stage; a heat exchanger or regenerator being included in the turbine exhaust.
Abstract: A gas turbine plant including a compressor section and a turbine section housed within a multipart casing with the shafts of each section co-axial, the compressor section including a double-sided low pressure radial compressor, a high pressure radial compressor and an inter-cooler, while the turbine stage includes a first stage axial turbine on the same shaft as the compressor and at least an additional turbine stage; a heat exchanger or regenerator being included in the turbine exhaust.

Journal ArticleDOI
TL;DR: In this article, the mean velocity profiles, turbulence intensities and shear stresses, and limiting stream-line angles are measured at various radial and chordwise locations, using rotating triaxial hotwire and conventional probes.
Abstract: Three-dimensional boundary layer and turbulence measurements of flow inside a rotating helical channel of a turbomachinery rotor are described. The rotor is a four-bladed axial flow inducer operated at large axial pressure gradient. The mean velocity profiles, turbulence intensities and shear stresses, and limiting stream-line angles are measured at various radial and chordwise locations, using rotating triaxial hot-wire and conventional probes. The radial flows in the rotor channel are found to be higher compared to those at zero or small axial pressure gradient. The radial component of turbulence intensity is found to be higher than the streamwise component due to the effect of rotation. Flow near the annulus wall is found to be highly complex due to the interaction of the blade boundary layers and the annulus wall resulting in an appreciable radial inward flow, and a large defect in the mainstream velocity. Increased level of turbulence intensity and shear stresses near the midpassage are also observed near this radial location.

Patent
09 Aug 1978
TL;DR: In this article, an exhaust device for a condensable-fluid axial-flow turbine, comprising an annular diffuser with an axial input situated at the output of the last stage of the turbine and a substantially radial output leading to a condenser which is divided into two zones, in one of which the pressure is lower than in the other, is presented.
Abstract: An exhaust device for a condensable-fluid axial-flow turbine, comprising an annular diffuser with an axial input situated at the output of the last stage of the turbine and a substantially radial output leading to a condenser which is divided into two zones, in one of which the pressure is lower than in the other, the outer wall of the diffuser with respect to the input flow into the duct having a circumferential suction slot which removes a fraction of the flow in the diffuser towards the lower-pressure part of the condenser, said wall further having a shape such that the pressure gradient measured at its surface in the flow direction is negative or zero at all points.


Patent
01 Aug 1978
TL;DR: In this paper, a wheel having an outer rim serving as a brace between two adjacent compressor disks and centripetal blading is used to accelerate the air through openings formed in the rim, to accelerate it and discharge it into a space surrounding the axis of the compressor.
Abstract: A device for moving air from the jet flow of an axial compressor of a gas rbine group, to be conducted along the axis of the group to the turbine to be cooled. The air is moved by a wheel having an outer rim serving as a brace between two adjacent compressor disks and centripetal blading which moves the air through openings formed in the rim, to accelerate it and discharge it into a space surrounding the axis of the compressor.

01 Nov 1978
TL;DR: In this paper, an analytical model was developed for predicting the onset of supersonic stall bending flutter in axial flow compressors based on two-dimensional, compressible, unsteady actuator disk theory.
Abstract: An analytical model was developed for predicting the onset of supersonic stall bending flutter in axial-flow compressors. The analysis is based on two-dimensional, compressible, unsteady actuator disk theory. It is applied to a rotor blade row by considering a cascade of airfoils. The effects of shock waves and flow separation are included in the model. Calculations show that the model predicts the onset, in an unshrouded rotor, of a bending flutter mode that exhibits many of the characteristics of supersonic stall bending flutter. The validity of the analysis for predicting this flutter mode is demonstrated.

Journal ArticleDOI
TL;DR: In this paper, a physical model for axial flow of dry powders through inclined rotating cylinders under conditions of open-ended discharge is presented, and the model has been solved numerically for a wide range of operating conditions.

Patent
19 Jul 1978
TL;DR: A gas turbine power plant has a gas turbine including both high-pressure and low-pressure turbine sections and a compressor with both high pressure and low pressure compressor sections, which are arranged on each of a pair of twin-shafts with a closed circulation system flowing through the compressor and gas turbine sections.
Abstract: A gas turbine power plant has a gas turbine including both high-pressure and low-pressure turbine sections and a compressor including both high-pressure and low-pressure compressor sections. One gas turbine section and one compressor section are arranged on each of a pair of twin-shafts with a closed circulation system flowing through the compressor and gas turbine sections. A nuclear reactor supplies heat to a working gas of the circulation system. Various by-passes for the working gas are provided which are controlled in response to operating conditions. In this way, the pressure of the working gas within the nuclear reactor and between the low and high pressure gas turbine sections is maintained substantially constant.

Patent
10 May 1978
TL;DR: In this article, a turbine-impeller pump is used for geothermal pumping with axial flow driving assemblies, and a lubrication system is provided for lubricating the thrust bearing assembly.
Abstract: A turbine impeller pump particularly for use in a geothermal pumping system has a casing with a hollow cylindrical stator or axle fixedly connected in the longitudinal axis thereof which stator or axle defines a flow passage for motive fluid and enables a rotor assembly to be rotatably mounted thereon. The rotor has spaced composite impellers which lie in assembled position in medially disposed pumping chambers in the casing having a suction inlet for fluid to be pumped and a discharge outlet for pumped fluid. The rotor further has first and second multi-stage axial flow driving assemblies disposed on opposite sides of the spaced composite impellers so that the motive fluid for driving the same can be passed to the respective adjacent composite impellers and delivered with the fluid being pumped. The oppositely disposed driving assemblies are positioned to substantially balance the axial forces acting across the rotor and a thrust bearing assembly is operatively associated with the rotor for overcoming any residual axial forces acting along the rotor during operation of the turbine-impeller pump. A lubrication system is provided for lubricating the thrust bearing assembly. Additionally, a geothermal pumping system utilizing a turbine-impeller pump as above described includes, a recirculating pumping assembly for recirculating a portion of the fluid being pumped to provide motive fluid for operating the respective first and second multi-stage axial flow driving assemblies. The lubrication system is preferably located at a point remote from the turbine-impeller pump.

Patent
06 May 1978
TL;DR: In this paper, a plurality of guide vanes are positioned circumferentially just before the non-inlet portion of the high pressure first stage nozzle 30 so as to align the flow from the noninlet part with that from the inlet portion, solving the mismatching problem.
Abstract: PROBLEM TO BE SOLVED: To improve the flow of steam entering from a speed governing stage nozzle to a high pressure first stage nozzle and enhance the performance of axial flow turbines used in steam turbines and gas turbines SOLUTION: High temperature and high pressure steam expands in a speed governing stage nozzle 10, flows through a speed governing stage moving blade 20 to work, flows from a chamber 7 into a high pressure first stage nozzle 30, works on a high pressure first stage moving blade 40, enters into a high pressure second stage nozzle 50, then similarly works on a high pressure second stage moving blade 60, to rotate a turbine rotational axis 80 The speed governing stage nozzle 10 has a circumferential nozzle with an inlet portion and a non-inlet portion for steam The steam flowing from the non-inlet portion is mismatched with the flow direction of the high pressure first stage nozzle 30, to degrade performance Therefore, a plurality of guide vanes 100 are positioned circumferentially just before the non-inlet portion of the high pressure first stage nozzle 30 so as to align the flow from the non-inlet portion with that from the inlet portion, solving the mismatching problem, making steam flow into the high pressure first stage nozzle 30, and thereby preventing degraded performance

01 Oct 1978
TL;DR: In this article, the overall blade element performances and the aerodynamic design parameters are presented for a 1.35-pressure-ratio fan stage, which was designed for a weight flow of 32.7 kilograms and a tip speed of 302.8 meters per second.
Abstract: The overall blade element performances and the aerodynamic design parameters are presented for a 1.35-pressure-ratio fan stage. The fan stage was designed for a weight flow of 32.7 kilograms per second and a tip speed of 302.8 meters per second. At design speed the stage peak efficiency of 0.879 occurred at a pressure ratio of 1.329 and design flow. Stage stall margin was approximately 14 percent. At design flow rotor efficiency was 0.94 and the pressure ratio was 1.360.

Patent
27 Apr 1978
TL;DR: In this article, the authors describe an engine with an air inlet (1) and an exhaust gas outlet (2), where the exhaust flows through two turbines in parallel and the flow is controlled by valves in the exhaust pipe.
Abstract: The engine (1) has an air inlet (2) and an exhaust gas outlet (3). Branches (17, 18) from the exhaust lead to two turbines (11, 8). The exhaust flows through these in parallel and the flow is controlled by valves (19, 20) in the exhaust pipe (3). Each turbine drives a compressor (5, 10) which delivers air to the engine inlet. The air flows through the two compressors in series. The second stage compressor (10) is smaller than the first stage compressor and its driving turbine (11) is smaller than the other turbine (8). Each turbine and therefore each stage of the compressor can thus be controlled independently.

Patent
30 Jan 1978
TL;DR: A discharge assembly for an axial flow compressor which places a diffuser which extends radially outwardly and axial outwardly adjacent the last row of rotatable blades to efficiently convert the swirl energy of the fluid into pressure energy without utilizing one or more arrays of stationary blades to straighten the flow before it enters the diffuser is described in this article.
Abstract: A discharge assembly for an axial flow compressor which places a diffuser which extends radially outwardly and axially outwardly adjacent the last row of rotatable blades to efficiently convert the swirl energy of the fluid into pressure energy without utilizing one or more arrays of stationary blades to straighten the flow before it enters the diffuser.

Proceedings ArticleDOI
09 Apr 1978
TL;DR: In this article, the authors investigated the propagation of a non-uniform upstream flow field through a rotating blade row using classical pneumatic instrumentation and hot wire anemometry, which allows one to determine the average flow values as well as the instantaneous blade-to-blade flow field.
Abstract: The aim of the investigation is to study the propagation of a non-uniform upstream flow field through a rotating blade row. The flow is investigated using classical pneumatic instrumentation and hot wire anemometry. The latter allows one to determine the average flow values as well as the instantaneous blade-to-blade flow field. These measurements were performed upstream and downstream of a low-speed axial compressor stage rotor. A triangular inlet total pressure distortion was generated with a grid system, movable in the circumferential direction. The hot-wire data were processed with a periodic sampling and averaging technique to obtain the three-dimensional blade-to-blade flow downstream of the rotor at mid-span. The modification of the blade wakes and the existence of large absolute flow angle fluctuations are evidenced for different relative positions of the distortion and stationary hot wire.Copyright © 1978 by ASME

Patent
02 Sep 1978
TL;DR: In this article, the authors proposed an approach to permit enlargement of the surge margin without reducing the maximum stage efficiency by arranging such that part of fluid on the high pressure side is introduced to an inducer tip portion of a vane wheel at an instant when the working point of the compressor reaches a point right before the surge point or in the neighborhood of a stall point.
Abstract: PURPOSE: To permit enlargement of the surge margin without reducing the maximum stage efficiency by arranging such that part of fluid on the high pressure side is introduced to an inducer tip portion of a vane wheel at an instant when the working point of the compressor reaches a point right before the surge point or in the neighborhood of a stall point. CONSTITUTION: When the working point of the compressor reaches a point right before the surge point or the neighborhood of a stall point, this is detected, and at the same time part of the high pressure fluid extracted from a high pressure section of the compressor is led through a duct 14 and an on-off valve 13 to a header section 13, and is injected as a high speed jet from jet ports 12a of an injection ring 12 into an inducer tip section 9c. In consequence, instable low speed fluid over a vane surface 8 is given energy to increase the insensity of turbulence, whereby the boundary layer is prevente from being peeled-off or re-attached. In this way, an effect of enlarging the surge margin is reliably obtained to permit stable operation. COPYRIGHT: (C)1980,JPO&Japio