DE1045178B - Three-shaft jet engine - Google Patents

Description

Three-shaft jet engine The invention is based on three-shaft jet engines with two axial compressors with a high number of stages working in countercurrent to one another and arranged one behind the other on concentric shafts, the axial compressors each having low or high pressure parts. In the known engines, which have only axial stages, the air drawn in must be deflected twice through 180 ' , once before the axial high-pressure stage and once after it. Deflection losses and also unfavorable, relatively large external radial dimensions of the engine must therefore be accepted. In order to remedy this, a double-flow radial compressor wheel known per se is arranged in the middle between the axial compressors as a further high-pressure stage, which conveys the combustion air into the annular combustion chamber or coherent combustion chambers arranged in a known manner around the rear axial compressor.

In a known engine design with a double-flow radial compressor processes this air sucked in directly from the environment and must therefore to achieve the required pressure ratio with a relatively large Diameter are executed.

Compared to a well-known arrangement, consisting of an axial The low-pressure part and the downstream single-flow radial part result from the object the invention has the advantage of greater performance without significantly increasing the entire engine length, because here in the otherwise rarely used space between the radial stage and turbines, the axial stages working in countercurrent to the front half of the engine are housed. In the upstream in front of the double-entry radial wheel between which is of course in diameter according to this directed cell wall and the outer wall of the axial part located annulus can easily add the additional and auxiliary devices can be arranged without the need for an additional magnification the frontal area and thus the frontal resistance of the aircraft had to become.

In a further development of the invention, use can be made of the known measure are made, after which the individual compressor high and low pressure parts mechanically independently of one another via the inner shaft or this enclosing hollow shaft, respectively are driven by different turbine stages, the high pressure parts a have a higher speed than the low pressure parts. According to the invention, this is considered to be constructive and proposed in an aerodynamically particularly advantageous manner, the two axial high-pressure parts and to arrange the double-flow centrifugal compressor on a common hollow shaft, driven by a turbine stage consisting of one or two turbine wheels will.

The invention is explained below with reference to the schematic representation an exemplary embodiment explained in more detail in the drawing.

The stages of each of the two compressors, which are coaxially arranged one behind the other and flow through in countercurrent to one another, are each combined to form a high-pressure and low-pressure group a and b . The two high-pressure groups a in the middle of the engine are followed by a double-flow radial compressor wheel c, in which both air flows, the one coming from the front and the one coming from the rear by deflection, are combined and fed to the outside via elbows d to the combustion chambers e.

The high-pressure axial parts a, a of both compressors together with the double-entry radial impeller d located in the middle form a mechanical unit which, according to known flow conditions, must rotate somewhat faster than the low-pressure parts.

The three groups are driven by turbine wheels at the rear, the front wheel f driving the low-pressure part of the rear compressor via an outer shaft g , the second wheel or second and third wheel h and i the combined high-pressure parts a, a driving it via a central shaft Shaft k and the rearmost wheel ni. the front low-pressure part b of the front compressor drives via an inner shaft n.

In the drawing are the fixed blades of the axial compressors, furthermore, the outer edge of the floors r is not drawn. The outer contour of the drawing corresponds to the inner contour of the housing.

The combustion chambers e are rotationally symmetrical to the longitudinal axis of the engine around. these arranged around. One can also use the drawn combustion chamber cross section e as the cross-section of an annular combustion chamber arranged coaxially to the engine longitudinal axis watch.

Claims (2)

PATENT CLAIMS: 1. Three-shaft jet engine with two axial compressors working in countercurrent to each other and arranged one behind the other on concentric shafts with a high number of stages, the axial compressors each having low and high pressure parts, characterized in that in the middle between the axial compressors as a further high pressure stage, a double-flow radial compressor known per se is arranged, which conveys the combustion air into the annular combustion chamber or agitated combustion chambers arranged in a manner known per se around the rear axial compressor. 2. Engine according to claim 1, in which the individual compressor high or low pressure parts are driven mechanically independently of one another by means of the inner shaft or the hollow shaft surrounding it, in each case by different turbine stages, the high pressure parts having a higher speed than the low pressure parts, characterized in that - eichnet that the two axial high pressure parts and the Doppelflutige Radialkonipressor are arranged on a common hollow shaft, which from one of one. or two turbine wheels existing turbine stage is driven. Considered publications: German Patent Specifications No. 875 282, 818 277; Swiss patents No. 263 472, 263 383; British Patent Nos. 659 151, 617 152; U.S. Patent No. 2,409,177; "Zeitschrift des VDI", Vol. 93 (1951), No. 31, p. 975; "The Airplane", Vol. 85 (1953), No. 2199, p. 376; Vol. 82 (1952), No. 2128, pp. 530, 531.