Wall and film temperature
Wall and film temperature
(OP)
Hi Guys, I'm just wondering how experts measure the wall and film temperature of let's say boiler tube. Did they measure it using instruments or theoretical approach? If I arrived at a particular value how would I know If I am close to the actual?
Thanks
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RE: Wall and film temperature
RE: Wall and film temperature
The latest laboratory measurents conducted by Siemens KWU ( Erlangen- Prof Keiffer, Kohler, Hein)used single, unfinned tubes heated by induction heating coils and controlled the heat flux- the tubes had installed chordal thermocouples every 3 " along the tube lenght. Teh occurrence of DNB and dryout was deermined, and the correlatios of KonKov and Dorishchuck were confirmed for smooth bore tubes.
For modern large furnaces, numerical modeling of the furnace combuston chanmber's fluid flow and heat transfer is conducted using a Galerkin method ( see Woody Fiveland's papers- B+W) and the expected radiation flux across teh furnace perimeter is estimated. The Siemens KWU correlations are used to confirm adequate water circulation to avoid DNB and dryout does not occur. The metal temperature is calculated over the tube's circumference using standard finited element models.
Currently