Experiments, to measure the heat transfer from dry saturated steam to rotating plain cylindrical surfaces on which the steam is condensing, were carried out with specially built apparatus. The range of pressure of the steam was from 20 to 80 psia., and three plain cylindrical nickel-plated mild-steel specimens were employed having diameters of 4, 8, and 10 inches, rotating at various speeds from 0 to 1500 r.p.m. The axial speed of the steam was small. The heat fluxes attained varied from 20,000 to 80,000 B.Th.U/ft.2hr. and the heat transfer coefficients varied between 1,000 wild 4,000 B.Th.U/ft.2hr.°F. For centrifugal accelerations up to 2 g the heat transfer coefficients were similar to the stationary-cylinder values, but above 2 g them; was an increase in these. Photographs of the rotating cylindrical surface taken during the experiments showed that the condensate forms a complete film on the surface and protrusions of condensate occur, towards which the condensed water flows. Eventually the protrusions become drops large enough to be thrown off the rotating surface by centrifugal force. These protrusions covered only a small amount of the surface, and it was calculated that the flow of the condensate between protrusions was laminar. Existing laminar-film condensation theory was adapted to rotational conditions. The theory used assumes laminar flow of condensate towards a protrusion under the influence of the components of centrifugal force acting along the condensate surface. The relations between the heat transferred and other variables are presented in the report both graphically and in the form of equations using; standard dimensionless factors. The results of the present experiments are compared with previous work in this field, and extensions of the results of the present work to a wider range of conditions are considered.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602250 |
| Date | January 1963 |
| Creators | Matthews, Derek Harcourt |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/13420 |
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