Experimental And Numerical Study On Film Flow Behavior On Large Scale Flat Plate

The safety performance of nuclear power plant is of great significance forlong term development of nuclear power. Many countries are buildingadvanced nuclear power plant of generation III. China is constructing theWestinghouse AP1000. AP1000containment utilizes passive containmentcooling system (PCCS) to provide the ultimate heat sink for decay heatremoval and to ensure the integrity of the containment. Based on AP1000technologies, the large advanced pressurized water reactor CAP1400is nowbeing designed in China with larger containment size and larger containmentcooling tank. The present study will provide theoretical foundations andtechnical supports for the design of PCCS of CAP1400through a deepunderstanding of mechanisms involved in water film behavior.Aiming at the research status, this paper conducts experimental studies onwater film behavior on large scale flat plate. Some reliable empirical relationsof parameters of film flow are obtained. The best practice guideline is giventhrough three dimensional numerical simulations. Based on the results of theexperimental data and simulation calculations, some primary suggestions onPCCS application are made.The main tasks of the present study consist of four parts, as summarizedbelow:1. Experimental study on water film behavior on large scale flat plate.The experimental facility is designed and constructed. The effect ofReynolds number, plate inclination, count-current air flow, surfacecharacteristics, and entrance condition on the film behavior is studied,such as film thickness; surface wave characteristics and film break up. Based on experimental data empirical correlations describing film flowparameters are developed2. Three-dimensional numerical simulation on water film behavior.A numerical model is established to simulate water film behavior on flatplate. The water film characteristics and break up behavior with andwithout count-current air flow are investigated. Numerical results arecompared with experimental data. The numerical study providescomplementary information to experimental data.3. Numerical study on flow and heat transfer behavior of surface wave.Numerical model is established to simulate flow and heat transfer behaviorin the solitary wave of the falling water film. The flow and temperaturefield inside the solitary wave provides evident to understand the effect ofsolitary wave scale and count-current air flow on the flow and heat transferperformance inside solitary wave.4. Application to PCCS.Based on both experimental and numerical studies, proposals are made onimprovement of heat removal capability of PCCS, such as surface coatingmaterial and geometric structure of entrance section, including distributionunit, of the falling water injection.This thesis is devoted to investigate flow and heart transfer characteristics offalling water film of PCCS. The effects of different factors are investigatedexperimentally and numerically. Based on comparison with experimental data,the applicability of the numerical approach used is proved. The resultsachieved in the thesis contribute significantly to a better understanding ofimportant mechanisms involved in water film flow of PCCS, and provideuseful knowledge to the establishment of mathematical and numerical modelsfor future investigation on PCCS related phenomena.