Resumo

ZIPFEL, T.  e  KROGER, D.G.. Flow loss coefficients at air-cooled condenser finned tube inlets. R&D j. (Matieland, Online) [online]. 1997, vol.13, pp.62-67. ISSN 2309-8988.

In a typical air-cooled steam condenser of a power generating plant, the turbine exhaust steam flows via a distribution pipe or dividing header into numerous finned tubes or laterals. The steam flow distribution in air-cooled condensers must be quantified to assure a sufficiently high steam flow rate into every lateral to avoid the accumulation of non-condensable gases in the lower section of any lateral. The flow through a lateralis, amongst others, a function of the flow resistance at the lateral inlet which can be expressed in terms of a loss coefficient. The magnitude of the lateral inlet loss coefficient as found in a typical air-cooled condenser is investigated experimentally. It is found that the inlet loss coefficients of the individual laterals vary, with the first lateral (upstream lateral) experiencing the greatest value. Furthermore it is observed that the inlet loss coefficients are a function of the dividing header flow velocity. A reduction in inlet loss coefficient can be obtained by placing a backward facing step or a small wedge-like ramp upstream of the first lateral or by installing a suitable grid near the lateral inlets.

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