The contributing factors for the cavitation in piezoelectric pumps areanalyzed, theoretically, and the device fitting for observing and recording is set up. With it theexperiments are carried out to observe the emerge...The contributing factors for the cavitation in piezoelectric pumps areanalyzed, theoretically, and the device fitting for observing and recording is set up. With it theexperiments are carried out to observe the emergence and the flowing of the cavitations in thepiezoelectric pumps. According to the statistic and the analysis to the data of the experiments, thepeculiar features are discovered. These features are composed of balls-amassing, center-more, andflow-out.展开更多
Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of t...Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of the effective blade sections.Effective blade sections are two-dimensional sections in two-dimensional flow which have the same chordwise loading distribution as the three-dimensional blade sections of a propeller.However,the design procedure is laborious in two aspects：finding an optimum blade section using the Eppler program requires much skill of the designer,and transforming the two-dimensional blade section into a propeller blade section in three-dimensional flow is complex.In this work,these two problems were coped with.A blade section design procedure was presented using an optimization technique and an alternative procedure for the effective blade section is developed using a lifting surface design method.To validate the method a benchmark model of a naval ship was used.This benchmark model was extended by new appendices and a reference propeller,and designed using conventional design methods.This reference propeller was optimized using the new design procedure and model tests were carried out.Special attention was given to the data of the model and the reference propeller,to make the configuration suitable for the Reynolds-Averaged Navier-Stokes（RANS）calculations.展开更多
文摘The contributing factors for the cavitation in piezoelectric pumps areanalyzed, theoretically, and the device fitting for observing and recording is set up. With it theexperiments are carried out to observe the emergence and the flowing of the cavitations in thepiezoelectric pumps. According to the statistic and the analysis to the data of the experiments, thepeculiar features are discovered. These features are composed of balls-amassing, center-more, andflow-out.
文摘Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of the effective blade sections.Effective blade sections are two-dimensional sections in two-dimensional flow which have the same chordwise loading distribution as the three-dimensional blade sections of a propeller.However,the design procedure is laborious in two aspects：finding an optimum blade section using the Eppler program requires much skill of the designer,and transforming the two-dimensional blade section into a propeller blade section in three-dimensional flow is complex.In this work,these two problems were coped with.A blade section design procedure was presented using an optimization technique and an alternative procedure for the effective blade section is developed using a lifting surface design method.To validate the method a benchmark model of a naval ship was used.This benchmark model was extended by new appendices and a reference propeller,and designed using conventional design methods.This reference propeller was optimized using the new design procedure and model tests were carried out.Special attention was given to the data of the model and the reference propeller,to make the configuration suitable for the Reynolds-Averaged Navier-Stokes（RANS）calculations.
