With increasingly stringent requirements for the airtightness of high-speed train bodies,determining appropriate airtightness levels has become critically important.To calculate the airtightness of high-speed train bo...With increasingly stringent requirements for the airtightness of high-speed train bodies,determining appropriate airtightness levels has become critically important.To calculate the airtightness of high-speed train bodies more accurately,based on one-dimensional isentropic flow theory,this study derives cabin pressure calculation models for both positive and negative pressure conditions during static airtightness tests of high-speed train bodies.Since the flow coefficient,which is closely related to the leakage characteristics of the carriage,is influenced by multiple factors including operating pressure conditions(positive/negative),leakage path cross-sectional shape,and size,a flow coefficient calibration method is proposed to achieve high-precision and efficient calibration of the flow coefficient for trains with varying leakage properties.This method generates a series of flow coefficient values for circular and square cross-sectional shapes under both positive and negative pressure conditions across various cross-sectional areas.Furthermore,functional relationships between flow coefficient and leakage path area under positive/negative pressure are established through curve fitting.Using these functional relationships and the cabin pressure calculation model,the pressure variation curves for a static airtightness test are simulated.Specifically,for circular cross-sectional shapes,the theoretical curves under positive and negative pressure conditions exhibited R^(2) values of 0.9936 and 0.9931,respectively,when compared to experimental data,and for square cross-sectional shapes,the corresponding R^(2) values are 0.9928 and 0.9932,validating the accuracy of the proposed theoretical model.The proposed theoretical model effectively evaluates the airtightness of high-speed train bodies with varying performance levels during static airtightness tests,providing a robust theoretical reference for optimizing high-speed train airtightness design.展开更多
基金Projects(52372402,U2568224)supported by the National Natural Science Foundation of China。
文摘With increasingly stringent requirements for the airtightness of high-speed train bodies,determining appropriate airtightness levels has become critically important.To calculate the airtightness of high-speed train bodies more accurately,based on one-dimensional isentropic flow theory,this study derives cabin pressure calculation models for both positive and negative pressure conditions during static airtightness tests of high-speed train bodies.Since the flow coefficient,which is closely related to the leakage characteristics of the carriage,is influenced by multiple factors including operating pressure conditions(positive/negative),leakage path cross-sectional shape,and size,a flow coefficient calibration method is proposed to achieve high-precision and efficient calibration of the flow coefficient for trains with varying leakage properties.This method generates a series of flow coefficient values for circular and square cross-sectional shapes under both positive and negative pressure conditions across various cross-sectional areas.Furthermore,functional relationships between flow coefficient and leakage path area under positive/negative pressure are established through curve fitting.Using these functional relationships and the cabin pressure calculation model,the pressure variation curves for a static airtightness test are simulated.Specifically,for circular cross-sectional shapes,the theoretical curves under positive and negative pressure conditions exhibited R^(2) values of 0.9936 and 0.9931,respectively,when compared to experimental data,and for square cross-sectional shapes,the corresponding R^(2) values are 0.9928 and 0.9932,validating the accuracy of the proposed theoretical model.The proposed theoretical model effectively evaluates the airtightness of high-speed train bodies with varying performance levels during static airtightness tests,providing a robust theoretical reference for optimizing high-speed train airtightness design.
