Research On Transportation Technique Of Three-phase Liquid In Pipeline

The pipeline is being applied more and more broad. On winch-suction dredgers, slurry is just transported by it. At present, this kind of dredgers can't carry slurry too long by two-phase liquid. Three-phase liquid piping is a new technique. The research purpose is to apply this technique to winch-suction dredgers, prolonging their transportation distance.Three-phase liquid piping is injecting compressed air into two-phase pipeline, and its resistance-decreasing and assistant thrust are utilized to prolong transportation distance. The theory on three-phase liquid piping is firstly researched in this thesis. The equation about pressure drop of three-phase liquid in a pipeline has been derived from the primary equations of invariable uniform liquid, and the equation has been calculated. The result indicates that the injected air will not change the pipe pressure much. In addition, the feasibility and superiority have been analyzed to prolong transportation distance with three-phase liquid piping.It is necessary to make model research on a test-platform in order to know the radical law of three-phase liquid piping. Based on flow state in pipeline of the dredger, the thesis analyzes the similarity relationship between the original model and analogue model. The conclusion is induced that resistance similarity is primary in pipeline similarity. It is the base to design test-platform and instruct model experiment.A computer data sampling system has been developed in the thesis. This system is consisted of aptitude meters and the supervising software developed with Visual C++. It has been applied to the experiment successful.Because the state of the air injected to pipeline will affect the flow form, the key problem to be solved in the research is to quest for appropriate air-injecting method. For the purpose of ensuring that the resistance won't increase, a few nozzles have been designed to experimentize. At last the water-air revolving spray ejecting air-ejecting mode as research emphasis is selected. A great deal of experiment has been made with water-air revolving spray nozzle. Reasonable air-ejecting parameters have been induced according to processing and analyzingthe experiment data.Based on the outcome of model experiment and similarity relationship, the air-injecting device applied to dredger has been designed. The application experiment of three-phase liquid piping has been made on 400m3/h winch-suction dredger with it. The experiment data have been processed and analyzed, and the result indicates that it is effective and applied to prolong transportation distance by three-phase liquid piping. The research is successful.