Experimental Study of the Flow Conditions and Pressure Drop of Steam-Water Mixtures at High Pressures in Heated and Unheated Tubes

The work described in the three parts of this paper was sponsored by the Water-Tube Boilermakers' Association and carried out in the Engineering Department of Cambridge University. In Part I are described the high-pressure experimental plant and its associated instrumentation. A description of the test circuit is followed by a detailed description of the construction and performance of the electrical low-frequency induction heaters specially developed to supply the power input to the test section. Auxiliary electrical resistance heaters are also described. The work required the development of special differential manometers and differential thermocouples suitable for the accurate measurement of small differences in pressure and temperature at high fluid pressures. Gamma-ray absorption equipment was used to make measurements of the apparent density of the two-phase mixture within a cross-section of the tube at the test-section outlet, from which estimates could be obtained of the relative or ‘slip’ velocit...