Numerical Analysis of Density Wave Oscillations in the Horizontal Parallel Tube Paths of the Evaporator of a Natural Circulation Heat Recovery Steam Generator
نویسنده
چکیده
The paper presents the results of a theoretical stability analysis on a vertical type natural circulation heat recovery steam generator. The evaporator of the boiler consists of four parallel horizontal tube paths, which are connected at both ends with headers. For different operation pressures and geometries the dynamic instability and in particular the density wave oscillation (DWO) was analysed. The investigations show that the stability of the boiler can be improved by increasing the system pressure. A faster decay of the DWO can be achieved by the implementation of an orifice at the tube inlet of the evaporator (single phase flow), whereas the installation of an orifice at the tube outlet (two phase flow) results in a more unstable behaviour. Key-Words: Density wave oscillation, Dynamic instability, Natural circulation, Horizontal parallel tubes, Heat recovery steam generator
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