Abstract: A coolable housing wall for hot gas fluid flow engines, especially for a gas turbine of the air jet type, is provided on its radially inwardly facing surface with a carrier for a single cover layer forming a running-in coating. The cover layer is applied by thermal spraying to form a ceramic coating having a high heat and corrosion resistance. The single cover layer has a substantially uniform thickness and projects radially inwardly from the carrier, preferably by forming ridges facing the blade tips of a rotor in the housing. Such cover layer also has a high erosion resistance.

Abstract: A gas turbine engine is so constructed that the clearance or gap between the rotor and stator, especially at the outer diameter range of a radial flow end stage, is optimally maintained under all operating conditions. For this purpose the housing in the axial-flow/radial-flow compressor is constructed as a two shell housing. The outer housing shell is mounted as part of the engine structure, whereby the inner housing shell is exposed substantially only to forces or loads caused by compressor fluid flow. The material of the outer housing shell has a heat expansion coefficient in the axial direction of the rotational engine axis, which is distinctly lower than the heat expansion coefficient of the material of the compressor rotor. The heat expansion coefficient of the material of the inner housing shell is lower in the circumferential direction and approximately equal in the axial direction relative to the heat expansion coefficient of the rotor.

Abstract: A hot gas impinged turbine blade suitable for use under super-heated gas operating conditions has a hollow ceramic blade member and an inner metal support core extending substantially radially through the hollow blade member and having a radially outer widened support head. The support head has radially inner surfaces against which the ceramic blade member supports itself in a radial direction on both sides of the head. The radially inner surfaces of the head are inclined at an angle to the turbine axis so as to form a wedge or key forming a dovetail type connection with respectively inclined surfaces of the ceramic blade member. This dovetail type connection causes a compressive stress on the ceramic blade member during operation, whereby an optimal stress distribution is achieved in the ceramic blade member.

Abstract: In an arrangement of at least two discrete structural parts in package form which are spaced apart from each other, the individual structural parts are coated at least on one circumference of the structural part with a metal- or ceramic-powder collar. The powder collars serve as spacers between adjacent structural parts, are preferably sprayed on, and reliably prevent fretting corrosion between the structural parts.

Abstract: Titanium alloy test samples including welded samples of such alloys are tested for recognizing textural or structural faults or flaws in the form of segregations or liquations. To make these flaws visible by increasing the contrast between a flaw and the background, an etching method including two etching steps is used, which achieves especially marked contrasts. The method is based on the selective solution removal of a phase, a grain, or of an impurity of an alloy type. An especially good visual recognition of segregations, liquations or inhomogeneities of welded test samples is made possible by the resulting matte gray surface against which lustrous flaws are clearly visible.

Abstract: An apparatus for the electrolytic drilling of precision holes into a work piece surface which extends at an acute angle to the drilling direction, has one tubular electrode for each hole to be drilled. Each electrode directs an electrolyte stream in the desired direction. In order to assure a proper drilling and to protect the work piece outside the holes to be drilled, a covering body is located to cover the work piece surface through which the holes are to be drilled. The covering body has a surface which closely hugs or forms an interface with the work piece surface, and another surface which extends perpendicularly to the drilling direction so that the drilling begins through the covering body which then forms a guide for the electrode and for the return flow.

Abstract: Components, such as bearings, of gas turbine engines especially for aircraft are lubricated by a lubricant supply system including a main lubricant circulating circuit and an auxiliary lubricant circulating circuit for assuring a sufficient lubricant supply to the lubricating chamber or chambers under all operating conditions including those causing extremely rapid and locally differing displacements of the lubricant fluid in its supply tank. The main lubricant circulating circuit with its pumps, lubricating chamber or chambers, cooler, air separator and accumulator is operatively connected to the component being lubricated and is effective during normal and critical flight conditions. The auxiliary circulatory circuit with its lubricant supply tank and its pump is operatively connected to the main circulatory circuit for supplying lubricant into the main circuit.

Abstract: The present axial-flow turbine blade has two cooling channels extending radially through the blade. These radial channels communicate with each other through impingement cooling ducts or holes (3) extending substantially axially through the blade. One channel (1) supplies cooling fluid through the holes (3) into the other channel (2) which is located nearer the leading edge (8) of the blade and extends substantially in parallel to the leading edge (8). The cooling fluid impacts on the wall of the other channel (2) and is laterally blown out at a side wall of the blade. For optimal cooling, especially of the leading edge of the blade, which is subject to severe thermal loads, this edge is penetrated by cooling elements (4) in the form of pins or wires in axial alignment with the impingement cooling holes or ducts (3). These cooling pins or wires (4) reach into the channel (2) nearer the leading edge with their tapered end (5) and are made of a highly thermally conductive material.

Abstract: A blade for a fluid flow engine, especially a gas turbine, has a protective coating against injurious attack by the propellant or working medium. A metal blade having a diffusion layer or a sprayed coating for inhibiting corrosion is known. Such coating renders the blade highly resistant against heavily erosive and corrosive attack, especially by pulverized coal combustion gas or similar agents. The present blade is made of ceramic material, especially a dense ceramic material with a surface layer of at least one of the following materials: TiN, TiC, B.sub.4 C, BN and titanium carbon nitride. These materials are easy to apply and provide a good bond with the ceramic material. If the ceramic materials are silicon carbide (SiC) or silicon nitride (Si.sub.3 N.sub.4) an especially good bond is achieved. This coating strongly resists removal, as it does oxidation and heat. Local removal down to the ceramic material, as it may result from rather long service, is recognizable immediately.

Abstract: A piezoelectric vibration exciter for generating mechanical vibrations for the purpose of destructive material or specimen testing has two equally sized disk stacks, each with an even number of piezoceramic disks. A vibration armature serving as a clamping device for the test specimen is arranged between the two disk stacks in a stiff clamping frame having a bail and a base plate. The assembly containing the disk stacks and the vibration armature is clamped in position in the stiff clamping frame. The piezoceramic disks are energized with an AC voltage so that one disk stack will axially contract in phase with the voltage, while the other disk stack will axially expand. As a result, the vibration armature and the test specimen arranged between the disks reciprocate at the frequency of the AC voltage input.

Abstract: A bath or electrolyte for the galvanic deposition of a metal matrix layer having embedded therein particles of a non-metallic substance, comprises a stabilizer for keeping such non-metallic substances uniformly suspended in the bath for the duration of the electrolysis. The suspension stabilizer is a cation active imidazole derivative satisfying the general formula ##STR1## wherein R.sup.1 is preferably a monovalent, saturated or unsaturated hydrocarbon radical having at least four aliphatically bound C-atoms, R.sup.2 is a methylene (carbene), or ethylene, or propylene or isopropylene group, and wherein X is selected from --NH.sub.2, --NHR.sup.3, --NR.sup.3 R.sup.4, --OH, or OR.sup.5, whereby R.sup.3, R.sup.4 and R.sup.5 are methyl, ethyl, or propyl or polyglycolether radicals having up to five --O--CH.sub.2 --CH.sub.2 groups.

Abstract: A bladed flow duct, for example in an axial flow turbo engine, is defined between two adjacent blades and the respective duct floor. In order to reduce secondary flow losses, the flow duct is provided with an arched zone (13, 13') projecting from the duct floor (10, 10') and extending along a portion of the suction side of the adjacent blade wall for producing a pressure rise or a reduction in the transverse pressure gradient over a relatively long forward and/or central portion of the duct as viewed in the flow direction (17) from the entrance end (21) to the exit end (22) of the duct. For this purpose the arched zone (13, 13') has a number of sections in the flow direction (17). A first section (23) starting in the entrance side of the duct is substantially or completely concave for causing said pressure rise. A second or central section (24) forms a convex peak and particularly a duct throat near the exit side of the duct. A third section (25) slopes down to the exit end (22).

Abstract: Disclosed is a variable flow divider for a turbomachine having a gas flow channel, comprising a stationary annular casing member located within the exhaust gas flow channel of the turbomachine, thereby defining an inner flow duct and an outer, annular flow duct; a plurality of flaps pivotally mounted in the flow channel on a stationary portion of the turbomachine, including a plurality of primary flaps and a plurality of secondary flaps adapted for rotation with the primary flaps, each of these flaps rotating about an axis which is arranged at a right angle to the central axis of the turbomachine; and means, located substantially entirely within the annular casing, for rotating said flaps to vary the respective sizes of said inner and outer flow ducts in relation to one another.