Abstract: The invention relates to a device for mixing two fluid flows, initially guided separately from one another, in a two-circuit reaction engine, a mixing tube which encloses a hot core stream being provided, along the outer shaped lateral surface of which a cold bypass flow flows. The mixing tube is designed in the form of a truncated cone narrowing in the direction of flow and has openings arranged at the downstream end in the circumferential direction of the mixing-tube lateral surface in a cross-sectional plane lying perpendicularly to the longitudinal axis of the mixing tube. The hot core stream flowing through the mixing tube penetrates through the openings into the cold bypass flow flowing around the mixing-tube lateral surface. The openings have passage areas of elliptical shape with a major axis and a minor axis, the major axis of the passage areas running on the lateral surface of the mixing tube in the direction of flow of the fluids and the minor axis running perpendicularly thereto.

Abstract: The invention relates to a device for mixing two fluid flows, initially guided separately from one another, in a two-circuit reaction engine, a mixing tube which encloses a hot core stream being provided, along the outer shaped lateral surface of which a cold bypass flow flows. The mixing tube is designed in the form of a truncated cone narrowing in the direction of flow and has openings arranged at the downstream end in the circumferential direction of the mixing-tube lateral surface in a cross-sectional plane lying perpendicularly to the longitudinal axis of the mixing tube. The hot core stream flowing through the mixing tube penetrates through the openings into the cold bypass flow flowing around the mixing-tube lateral surface. The openings have passage areas of elliptical shape with a major axis and a minor axis, the major axis of the passage areas running on the lateral surface of the mixing tube in the direction of flow of the fluids and the minor axis running perpendicularly thereto.

Abstract: The invention relates to a friction welding process for mounting blades of a blade carrier (1) of a flow machine as well as a shielding gas shower for supplying gas to welding surfaces. To achieve this, a plurality of longitudinally extending welding surfaces (5a) are provided on the circumference of the blade carrier (1), are oriented at a blade angle &bgr; relative to the rotation axis (R) of the blade carrier (1), and are respectively welded together with a welding surface (5b) of a blade (2). The welding temperature necessary for joining the bodies (blade carrier (1), blade (2)) is achieved by pressing together the welding surfaces (5a,b) and simultaneous oscillating relative motion (P) of the bodies (1, 2) in the welding plane (E), whereby a shielding gas (S) flows around the welding surfaces (5a,b) during the relative motion (P). The shielding gas flow S follows the contour of the blade carrier and the blade and thus serves to provide a closed shielding gas curtain for protecting the welding surface.