| This paper combined with experimental research and theoretical analysis to probe the reason that liquid converted to two-phase flow in vacuum pipe.And the flow patterns were classified,the reason that measured value of flow and pressure drop were different from the theoretical value was analyzed,and then combined with test data to deduce the calculation formulas which applyed to obvious pseudo-cavitation,installation height less than 8m of flow and pressure drop of non-hump siphon.Experimental research included that flow patterns of two-phase flow were classified, pseudo-cavitation in vacuum tube was revealed. The change laws of flow and pressure drop by testing were obtained,and the theoretical analysis was combined to find the difference between measured value and theoretical value.Theoretical analysis included that calculation formulas on different flow patterns were deduced of flow and pressure drop. Validation results showed that: relative error was controlled into ±5% and ±7% which calculated by formula derived of flow and pressure drop of horizontal pipes, relative error was controlled into ±6% which calculated by formula derived of vertical pipes.The errors were too smaller to illustrate the formulas were suitable. |
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