The Quantitative And Accurate Calculation For Flow Passage Performance Of Steam Turbine Based On Characteirstic Flow Area

The performance of steam turbine flow passage can affect the operation economicalefficiency of the unit. It is highly significant to evaluate it exactly in operation. The definitionand calculation method of the characteristic flow area which based on Flügel Formula aremainly expound in this thesis. Using the method calculate and analysis the flow passageperformance of the units quantificational, the model which could meet the realistic accuracyin the steam turbine’s flow passage performance accurate calculation by the improvedcomputing method of steam parameter. This model can be applied to the power plant steamturbine flow passage monitoring.First of all, the characteristic flow area of steam turbine is calculated through derivationand evolvement of Flügel Formula. On the basis of original data, calculating and analyzingcharacteristic flow area, characteristic flow area deviation, specific characteristic flow area oftwo representative units, proving the formula through utilizing case of project. The resultsshow that high off-design condition calculation accuracy and good performance totally meetsthe project requirements. It is feasible to apply in the field of variable characteristic flow areacalculation，monitoring and diagnosis of steam turbine. it is feasible to apply in the field ofimproved design of the flow passage, variable characteristic flow area calculation, monitoringand diagnosis of steam turbine.Secondly, this paper elaborates the state of water vapor in low pressure steam zone ofsteam turbine and IAPWS-IF97 formula, by analyzing the process of calculating water andsteam, putting forward relevance formula which can gain the steam parameter accurately,proving and analyzing by definite data, combine the formula and calculate method ofcharacteristic flow area, and then reduction, can get the new expression, using this expression,we can obtain the practical change of steam turbine flow passage by calculating the change ofcharacteristic flow area.Finally, on the basis of the IAPWS-IF97 formula, calculation software of characteristicflow area for steam turbine flow passage under the Visual Basic software platform wasdeveloped, introducing the software boundary and processing simply and by taking the600MW supercritical units made in China as the research object. It can calculate and analysisthe characteristic flow area for steam turbine under off-design condition.