Steam Release into Buildings: The Modelling of Steam Condensation

摘要

A lumped-parameter code, HOTSTM, has been developed to model the thermal transient resulting from a steam jet discharging into a large ventilated building, typical of CEGB power plant installations. The code is designed to deal with high pressure steam jets whose typical dimension is small compared with that of the building, so that there is good good mixing within the building. An important factor in limiting the temperature rise of the air/steam mixture is heat transfer to the internal surfaces of the building, the temperatures of which are significantly affected by condensation. A detailed description is given of the method used in HOTSTM to calculate condensation and evaporation on internal building surfaces. The method exploits the well-known analogy between heat and mass transfer, together with correction factors derived from a simplified analytical solution. The validity of the approximations inherent in the method is estimated to affect predictions of bulk gas temperature by only a few degrees. A complete listing of the code, as used for calculating thermal transients in Bradwell Turbine House, is appended to the Report. This is intended as a record of the calculational route used in that work, not as a user's guide to the program. (ERA citation 13:018099)