Investigation of heat transfer from condensing steam-gas mixtures and turbulent films flowing downward inside a vertical tube

This research experimentally investigates the local heat transfer from condensation of steam in the presence of noncondensable gases and from condensation of pure vapor in turbulent films at high Reynolds numbers. A novel experimental apparatus was designed and constructed for accurately measuring local heat fluxes. This research was performed as part of an effort to support the design of the Passive Containment Cooling System Condensers and Isolation Condensers of the General Electric's Simplified Boiling Water Reactor.; Forty-two test runs with pure steam condensation were performed with liquid films in the laminar range. Using the classical Nusselt solution as the reference state, a correlation for laminar film condensation was obtained using hydrodynamic calculations to determine the interfacial shear effect on film thinning, and using data to correlate the waviness effect against the film Reynolds number. Seventy-one runs with steam-air mixtures and 24 with steam-helium mixtures were performed to investigate condensation phenomenon in the presence of noncondensable gases. Three different correlations, one implementing the degradation method, initially proposed by Vierow and Schrock, a second diffusion layer theory initially proposed by Peterson et al., and a third fundamental mass transfer conductance model, are presented.; Approximately 300 test runs were performed to evaluate the film Reynolds number and interfacial shear effects on turbulent film local heat transfer. An extended data base for film Reynolds number and interfacial shear was generated. A phenomenologically-based approach was developed to treat heat transfer in the near-wall and near-interface regions separately, and to combine the two thermal resistances in series. A "two-layer thermal resistance model" was developed using theoretical and empirical methods. Without interfacial shear, heat transfer coefficients in the near-wall layer were theoretical determined using an integral analysis. The heat transfer coefficients in the near-surface layer were correlated from the experimental data. In the presence of interfacial shear, the ratios of local Nusselt numbers between sheared and unsheared flows were then correlated by curve fit to the data, using the scaling parameters obtained from the surface eddy renewal theory.