Taking the accelerometer installation errors into consideration, the attitude optimization algorithm of Gyro Free Inertial Meastement Unit （GFIMU） is studied in the high spinning condition in this paper. A ten-accel...Taking the accelerometer installation errors into consideration, the attitude optimization algorithm of Gyro Free Inertial Meastement Unit （GFIMU） is studied in the high spinning condition in this paper. A ten-accelerometer configuration is designed so as to establish a mathematical model to acquire the angular speeds in the case of installation errors. Precision of the algorithm is evaluated by using damping GaussNewton method. A large amotmt of sinmlation results show that ff the accelertlmter＇s angleinstallation errors main-tain small （〈5°）, the errors of attitude angles can be limited within ±1°. Hence, the algorithm has a great applicable value in engineering.展开更多
Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics.The purpose of this work is to investigate the influences of lean angle at the blade tip of the ...Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics.The purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller inlet.Four variations of lean angles,that is,8°,10°,15° and 20°,were made at first stage impeller.Reynolds Average Navier Stokes equation was used in simulation together with a shear?stress transport(SST) k-w turbulence model and mixing-plane approach,respectively.Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required.A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary flow.The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage,which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of impeller.The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.展开更多
基金supported by National Key Laboratory for Electronic Measurement and Technology(No.9140C120401080C12)
文摘Taking the accelerometer installation errors into consideration, the attitude optimization algorithm of Gyro Free Inertial Meastement Unit （GFIMU） is studied in the high spinning condition in this paper. A ten-accelerometer configuration is designed so as to establish a mathematical model to acquire the angular speeds in the case of installation errors. Precision of the algorithm is evaluated by using damping GaussNewton method. A large amotmt of sinmlation results show that ff the accelertlmter＇s angleinstallation errors main-tain small （〈5°）, the errors of attitude angles can be limited within ±1°. Hence, the algorithm has a great applicable value in engineering.
基金Project(NRF-2010-013-D00007) supported by the National Research Foundation of KoreaWork finacially supported by the 2010 Research Professor Fund of Gyeongsang National University,Korea
文摘Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics.The purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller inlet.Four variations of lean angles,that is,8°,10°,15° and 20°,were made at first stage impeller.Reynolds Average Navier Stokes equation was used in simulation together with a shear?stress transport(SST) k-w turbulence model and mixing-plane approach,respectively.Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required.A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary flow.The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage,which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of impeller.The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.
