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Abstract

The constant-pressure heat capacity, Cp, and local forced convection heat transfer coefficient, h, for water-oxygen mixtures flowing inside horizontal smooth tubes were obtained experimentally. Data were obtained for pressures of 24 to 26 MPa; flow rates 0.636 to 1.27 l/min, average heat fluxes 34 to 160 kW/m², mass velocities 351 to 701 kg/m²s and temperatures from 330 to 430 °C. Oxygen flow was 2 to 8 weight percentage of the total mixture flow. For a given flow and heat supplied to the mixture, Cp is determined from the bulk temperature in a heated tube. The heat transfer coefficient, h is determined from the difference in bulk and wall temperatures. The temperature at which the maximum heat capacity occurs (Tpc) is lower for water-oxygen mixtures than for pure water. Another effect of oxygen addition is a reduction in magnitude of the maximum Cp and h. The enhancement near the critical point appears to be less at high heat flux.