Showing papers on "Axial compressor published in 1972"

The motion of a vortex filament with axial flow

Abstract: Infinitesimal waves on a uniform vortex with axial flow are studied The equation for the frequency of helical waves is obtained, and solved for the case of long waves which leave the internal structure almost unaltered A method is developed to obtain results for vortices of non-uniform structure and for displacements which are not necessarily small compared with the core radius The approach consists of balancing the Kutta—Joukowski lift force, the momentum flux due to the axial motion, and the ‘tension’ of the vortex lines A general equation for the motion of a vortex filament is obtained, valid for arbitrary shape and internal structure, and in the presence of an external irrotational velocity field When the axial flow vanishes, the method is equivalent to using the Biot—Savart law for the self-induced velocity, with a suitable cutoff The impulse of a vortex filament is discussed and its rate of change is given

Effect of grooved casing treatment on the flow range capability of a single-stage axial-flow compressor

Abstract: Comparisons of the results of testing a single-stage axial-flow compressor with a solid-wall casing and with grooved casings are presented. The depth, location, and number of circumferential grooves in the casing over the casing over the rotor tip were varied. The near-stall weight flow was lower than that with the solid-wall casing for all but one grooved configuration indicating an improvement in the stall margin. The greatest reduction in the near-stall weight flow was noted for the configuration with five grooves located over the blade midchord region.

Fixed blading of axial compressors

Abstract: Fixed blading for an axial compressor constituted by a succession of blades fixed on at least one annular wall and a method of operating the same. Fluid passing through a passage between adjacent blades is drawn into a suction opening and the pressure at the suction opening is maintained substantially equal to the flow static pressure in the passage.

Centrifugal separator having axial-flow vortex generator

Abstract: In a centrifugal separator having a hollow cylindrical casing with coaxial inlet and outlet zones through which a particleladen medium is flowed, airfoil means is provided in the inlet zone for creating a vortex in the casing to separate the particles from the medium. The airfoil extends radially into the inlet zone and has a leading edge facing upstream and a tip located centrally in the flow stream. As the medium flows at a high velocity across the airfoil a vortex is generated downstream of the tip and in the casing. A layer of porous material lines the inside of the casing to capture the particles which are separated from the medium by the centrifugal action of the vortex. A continuous helical vane extends between the inlet and the outlet to channel the swirling fluid in a helix as it flows through the casing. In one embodiment, a venturi-shaped insert is provided in the casing and an axial-flow fan is provided in the outlet zone for inducing a draft in the inlet zone to maintain the velocity of the medium in the inlet zone at a sufficiently high level to ensure generation of a vortex.

Compound brayton-cycle engine

Abstract: A system is disclosed incorporating a reciprocating-piston compressor and drive arrangement for converting a portion of the heat of a working fluid to attain a pressure increase, with the resulting working fluid supplied to a turbine. As disclosed, the reciprocating structure is a free-piston engine with the compressor piston and drive-engine piston an integral structure. The housing of the free-piston structure incorporates cooling structure, for example so that the reciprocating compressor may approach isothermal operation. As disclosed, working fluid is heated to drive the free-piston engine, exhausting to drive the turbine which supplies mechanical output power. Also as disclosed, the turbine drives a rotary compressor or supercharger, which supplies intake fluid to the free-piston compressor, the output of which supplies the heater.

Analytical correlation of centrifugal compressor design geometry for maximum efficiency with specific speed

Abstract: Centrifugal compressor performance was examined analytically to determine optimum geometry for various applications as characterized by specific speed. Seven specific losses were calculated for various combinations of inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, blade exit backsweep, and inlet-tip absolute tangential velocity for solid body prewhirl. The losses considered were inlet guide vane loss, blade loading loss, skin friction loss, recirculation loss, disk friction loss, vaneless diffuser loss, and vaned diffuser loss. Maximum total efficiencies ranged from 0.497 to 0.868 for a specific speed range of 0.257 to 1.346. Curves of rotor exit absolute flow angle, inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, head coefficient and blade exit backsweep are presented over a range of specific speeds for various inducer tip speeds to permit rapid selection of optimum compressor size and shape for a variety of applications.

Performance of tandem-bladed transonic compressor rotor with tip speed of 1375 feet per second

Abstract: The design and experimental performance of a 20-inch diameter tandem-bladed axial-flow transonic compressor rotor is presented. Radial surveys were made of the flow conditions. At design speed the peak efficiency was 0.88 and occurred at an equivalent weight flow of 63 pounds per second. At peak efficiency the total pressure and total temperature ratios were 1.77 and 1.20, respectively. The stall margin at design speed was 10 percent based on weight flows and total pressure ratios at peak efficiency and near stall.

Turbomachinery and method of manufacturing diffusers therefor

Abstract: A radial flow compressor is described which includes a diffuser having an annular entrance chamber surrounding the circumferential discharge of the impeller of the compressor. Diffuser channels extend from this annular chamber to an axial flow diffuser from which the compressed air is discharged into a collection chamber. The annular chamber is provided with contoured nodes from which the channel diffusers respectively extend at relatively low angles, tangentially in relation to the periphery of the impeller.

Tangential Flow Development for Laminar Axial Flow in an Annulus with a Rotating Inner Cylinder

Abstract: The numerical finite-difference procedure of Gosman et al. (1969) is used to predict the growth of the tangential velocity profile and boundary-layer displacement thickness across an isothermal laminar axial flow through a concentric annulus when the inner cylinder is rotated at speeds which are insufficient to generate Taylor vortices. Solutions are obtained for fully developed and for developing axial flow over the ranges 0.05 $

Power modulation of a thermal generator

Abstract: A process for modulating the power of a gas turbine by variation of the inlet temperature of the working fluid in a compressor located upstream of a turbine. The compressor and turbine are each staged and the working fluid is cooled at least before the last compressor stage by gasification of a liquefied gas. A portion of the cooling energy produced by expansion of the liquefied gas can be returned to the liquefied gas in storage to cool the latter.

Axial flow hydraulic turbine generator installation

Abstract: A hydraulic turbine generator installation wherein the turbine rotor is supported centrally within a water confining tube and the generator rotor is supported by a ring connected to the radially outer ends of the turbine blades and rotates with the turbine blades. The blades are supported by the ring and a hub located in the tube to permit pivotal movement thereof. Hydraulic servomotors or the like are also supported by the ring and are connected to the blades to pivot the blades. A single power source for the servomotors is located on a stationary portion of the installation and connected by conduits through the turbine blades.

An Approximate Analysis of the Unsteady Lift on Airfoils in Cascade

Abstract: An approximate analysis is presented for determining the unsteady lift on airfoils in moving cascades, subject to disturbances in the inlet axial flow. The equations of motion are averaged across the pitch, and the mean pressure in each channel and the pressure difference across it are obtained. The lift on a reference blade dividing two blade channels is then estimated. The analysis is limited to flows in which the frequency parameter based on blade pitch is small, and to blading of low lift coefficient. Comparisons are given with earlier analyses, for flow past isolated airfoils (Sears), for quasi-steady flows through cascades (Gearhart, et al.), and for flow through an actuator disk of small blade chord and flow through cascades of flat blades (Whitehead).

Boundary Layers on Rough Compressor Blades

Abstract: Blades of axial flow compressors are often roughened by corrosion or erosion. There is only scant information about the influence of this roughening on the boundary layers of the blades and thereby on the compressor efficiency. To obtain detailed information for calculating the efficiency drop due to the roughness, experimental investigations with an enlarged cascade have been executed. The results enabled to develop new formulas for a modified friction coefficient in the laminar region and for the laminar-turbulent transition and the separation points of the boundary layer. Thus, together with the Truckenbrodt theory, it was possible, to get a good reproduction of the experimental results.Copyright © 1972 by ASME

Blade transition for axial-flow compressors and the like

Abstract: A transition of improved design for joining the merging surfaces of the airfoil and platform of an axial-flow compressor blade of the cantilevered type The transition as viewed in profile is a line comprising (a) an essentially straight major portion diverging outwardly from and faired into the airfoil and (b) an outwardly concave minor portion extending along and faired into the platform

The characteristics of axial flow electric arcs subject to pressure gradients

Abstract: Theoretical calculations are presented for the steady-state characteristics of electric arcs in accelerating axial flows having a stagnation point at the origin. The calculations are based on laminar flow heat transfer processes, and show good agreement with published measurements on nitrogen and air arcs in nozzle flow extending up to power gradients of 45×104 kW m−1.

Performance of a 1380-foot-per-second-tip-speed axial-flow compressor rotor with a blade tip solidity of 1.3

Abstract: Aerodynamic design parameters are presented along the overall and blade element performance, of an axial flow compressor rotor designed to study the effects of blade solidity on efficiency and stall margin. At design speed the peak efficiency was 0.844 and occurred at an equivalent weight flow of 63.5 lb/sec with a total pressure ratio of 1.801. Design efficiency, pressure ratio, and weight flow 0.814, 1.65, and 65.3(41.1 lb/sec/sq ft of annulus area), respectively. Stall margin for design speed was 6.4 percent based on the weight flow and pressure ratio values at peak efficiency and just prior to stall.

Four vane elliptical rotary air conditioning compressor

Abstract: A rotary hermetically sealed refrigerant electric compressor having an elliptically shaped compression chamber in which a symmetrical rotating rotor, keyed on the drive shaft in an axially slidable manner, includes opposed pairs of sliding vanes providing an inherently balanced bearing loading. The shear forces caused by the compressor rotor revolving against the lower bearing plate are reduced by incorporating a thrust element between the electric motor rotor and stationary hub portion of the upper bearing plate allowing limited movement of the compressor rotor on the shaft in an axial direction to provide for out of squareness dimensional tolerances between the compressor rotor, the shaft and the compression chamber.

Analytical Studies of Aircraft Trailing Vortices

Abstract: : The effects of turbulent mixing and buoyancy on the motion and persistency of a trailing vortex wake behind an aircraft are considered. A model for the characteristics of a turbulent vortex, based on an analogy to a turbulent boundary layer, is presented. A theory of trailing-vortex characteristics behind an aircraft is presented. A theory of trailing-vortex characteristics behind an aircraft is presented based on considerations of the angular and linear momentum of the vortex and the total pressure variation along the axis. The turbulent shear of the axial flow is analyzed and the model of a buoyant vortex wake is presented.

Composite variable oil pressure relief and compressor unload valve assembly

Abstract: An axially shiftable piston is pressure biased by screw compressor oil pressure to a position closing off communication between the intake and the discharge sides of an axial screw compressor but is biased to the unload position by the compressor discharge and a biasing spring acting on the same. The piston carries a fixed or variable oil pressure relief valve to vary the compressor oil pressure with change in compressor thrust load which, in turn, varies with the compressor discharge pressure.

Apparatus for cooling an electrical generator

Abstract: A gas driven turbo-generator set including a compressor for the working medium fed to the turbine to drive the generator and compressor and wherein the generator is cooled by circulating the working medium through it from an extraction point on the compressor.

Axial flow unit

Abstract: An axial flow unit is provided having a cylindrical rotor with impeller blades extending radially inwardly from the inside wall of the rotor and terminating in an elongated knife-like cutting edge. The radial distance of the cutting edge of each blade from the inside rotor wall progressively increases from one end of the blade toward its opposite end. The blades are arranged in helical symmetrical relation about the major longitudinal axis of the rotor, and a blade profile in a plane normal to that axis provides a projection with each blade in spaced relation to an adjacent blade.

Computer program for preliminary design analysis of axial-flow turbines

Abstract: The program method is based on a mean-diameter flow analysis. Input design requirements include power or pressure ratio, flow, temperature, pressure, and speed. Turbine designs are generated for any specified number of stages and for any of three types of velocity diagrams (symmetrical, zero exit swirl, or impulse). Exit turning vanes can be included in the design. Program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, blading angles, and last-stage critical velocity ratios. The report presents the analysis method, a description of input and output with sample cases, and the program listing.

Axial flow reversible fan

Abstract: The axial-flow reversible fan disclosed consists of a sectional housing mounting impellers which produce an air flow during the operation of the fan Disposed steamwise inside the housing is a device for straightening and guiding the air flow equipped with rotaty guide blades The latter have a concavo-convex aerodynamical profile in the passage section and have a trapezoidal shape in the non-passage section, the major base of said trapezium being made along the radius of the fan, while the chords are equal to 2 pi R/Z, where R is the radius varying within the length of the rotary guide blade and Z is the number of these blades The rotary guide blades through their tails are connected to the mechanism which provides for turning the blades through an angle close to 180*