Siemens Aktiengesellschaft

Gerd Urban

Heinrich Opitz

Bernhard Montag

Gert Mages

Wilfried Turk

The invention relates to a method and apparatus for heat exchange, especially for cooling at solid surfaces. At the solid surfaces, a locally uniform convective heat exchange is achieved. According to the invention, a sink flow is superimposed on a circular flow of a fluid in a flow chamber (1) at a surface of a heat-conducting solid wall (9) by means of a distributor, forming a vortex sink flow. The heat exchange surface of the component (9) to be cooled is at the same time the base plate (8) of a flow chamber (1).

Method and apparatus for heat exchange at solid surfaces

For the recording of local boundary-layer flow-line directions in liquid media by means of a photographic layer,

Method for recording local boundary-layer flow-line directions in liquid

The disclosed method relates to a method for recording flow boundary layers in liquid media by photochemical means. According to the invention, surfaces which can be developed in a plane and to which a photographic film sheet is cemented are exposed under steady-state conditions to the flow of a liquid medium containing a dissolved agent reacting with the photo gelatin layer. The liquid medium may contain agents furnishing HS-ions or agents capable of dissolving silver halide or reducing silver halide. If a photographic film sheet is used, the silver ions of which are reduced to silver, the flow exposure is performed with an agent having oxidizing and dissolving action. With the method disclosed, half-tone photograms of flow boundary layers in liquids can be recorded.

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Erlangen, Germany

Gerd Urban