Wang C.,University of Jinan |
Gao C.-Q.,University of Jinan |
Jia H.-T.,No.703 Research Institute of China Shipbuilding Industry Corporation
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2012
A new method was proposed to calculate the sliding friction power losses in double helical gears by considering the geometry and load contact characteristics of double helical gears based on three-dimensional high contact ratio conjugate meshing theory. Firstly, the paths of contact points on tooth surface were obtained from tooth contact analysis (TCA) of double helical gears. Secondly, the normal force of discretized points on the major axis of instantaneous contact ellipse and the loaded transmission errors of instantaneous contact points were calculated from loaded tooth contact analysis (LTCA) of double helical gears. Then, the normal force of discretized points and the loaded transmission errors were transformed into the normal force and relative sliding speed of instantaneous contact points, respectively. Multiplying these two with the friction coefficient causes the sliding friction power losses of instantaneous contact points. Finally, the sliding friction power loss from gear-in to gear-out is obtained by fitting and integrating the power losses of instantaneous contact points.
Yu G.,Harbin University of Science and Technology |
Yu G.,Harbin Institute of Technology |
Chen J.,Harbin University of Science and Technology |
Li J.,Harbin University of Science and Technology |
And 3 more authors.
Energy and Fuels | Year: 2014
Large eddy simulation (LES) of the gas-second order moment (SOM) of particles model based on the two-fluid method coupled with the subgrid-scale (SGS) reaction submodel is applied to investigate SO2 and NO x emissions in circulating fluidized bed (CFB) combustors. The SGS reaction submodel based on the eddy dissipation concept (EDC) model is developed considering the effect of particles to calculate the SGS reaction rates. The predicted results by the model are in good agreement with the experimental data. The flow characteristics including concentration and SOM of particles are analyzed. The simulation results show the particles including coal particles and desulfurizer particles are mixed sufficiently. The velocity fluctuation of particles is enhanced for the combustion process, and the velocity fluctuation in the axial direction is about 2 times higher than that in the radial direction. The reaction characteristics including the molar fraction of species and the distribution of chemical reaction rates with concentrations are also obtained. It can be found that the SGS reaction rates not only improve the homogeneous reactions of gas but also influence the heterogeneous reactions. © 2014 American Chemical Society.
Wang Y.,Harbin Institute of Technology |
Wu S.,Harbin Institute of Technology |
Chen M.,No. 703 Research Institute of China Shipbuilding Industry Corporation |
Cao Q.,Harbin Institute of Technology |
And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2011
The atomization characteristics of a gas/liquid coaxial swirling nozzle in pressurized space were investigated. Under different background pressures, the Sauter mean diameter (SMD) affected by the background pressure, the relative velocity of atomization gas to oil and the oil velocity were studied through measuring the size distribution of the droplets with 70 mm to the exit orifice by Phase Doppler Particle analyzer (PDPA). The results show that when the relative velocity of atomization air to oil and oil velocity are fixed, SMD decreases as the background pressure increases; when the background pressure and oil velocity are fixed, SMD decreases as the relative velocity of atomization air to oil increases; under the condition of fixed atomization air pressure and background pressure, the affection rule of the oil velocity on the SMD has an inflexion. SMD increases firstly and decreases lately as oil velocity rises. Based on the experiments, the inflexion value is 9.91 m/s. Correlations between SMD and background pressure, relative velocity of atomization air to oil and oil velocity were analyzed according to the examination data. © 2011 Chinese Society for Electrical Engineering.
Jiang J.-K.,Northwestern Polytechnical University |
Fang Z.-D.,Northwestern Polytechnical University |
Jia H.-T.,No. 703 Research Institute of China Shipbuilding Industry Corporation
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015
A method based on the minimization of LTE amplitude, axis force and vibration were proposed to reduce the vibration of double helical gears. The modified tooth surfaces were represented by the sum of two vector functions, describing respectively the theoretical tooth surface and the deviation surface. A 10-DOF vibration model was established considering the excitations of time-varying meshing stiffness, corner meshing impact and axial motion based on TCA and LTCA. An improved algorithm was applied to optimize the parameters of modified pinion for getting the best performance. The results show that the loads will tend to be uniform when taking the measures of gear modification and axial motion. Besides, torsional vibration mainly results from corner meshing impact and meshing stiffness excitation which have little effect on axial vibration. The axial motions excitation contribute to both axial and swing vibrations. In brief, the vibration decreases greatly because of smaller excitations by modified double helical gears. ©, 2015, Chinese Vibration Engineering Society. All right reserved.
Zhang R.,Harbin Engineering University |
Zhang R.,Dalian Nationalities University |
Yin L.,Harbin Engineering University |
Gu H.,No. 703 Research Institute of China Shipbuilding Industry Corporation
Jisuanji Yanjiu yu Fazhan/Computer Research and Development | Year: 2013
It is necessary for AUV to real-time perceive the influence degree of current uncertain events of ocean environment, AUV status and mission executive on the task, and to provide trigger condition to re-planning during mission. An environment perception for AUV in uncertain ocean environment is proposed. Environment perception makes use of the idea that heterogeneous real-world data of different types must be processed by uncertain event detection layer and uncertain event recognition layer. The uncertain event detection method is based on ontology reasoning and fuzzy logic, and the uncertain event recognition method is based on Bayesian network. The results of uncertain event detection and uncertain event recognition are used to the update uncertain environment ontology mode extended by probability description. In this way, environment perception method for AUV in uncertain ocean environment extends the ability of uncertainty presentation and reasoning in ontology. Navigation experimental results show the effectiveness of environment perception method for AUV in uncertain ocean environment.
Jiang J.,Northwestern Polytechnical University |
Fang Z.,Northwestern Polytechnical University |
Jia H.,No. 703 Research Institute of China Shipbuilding Industry Corporation
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2014
An approach based on CNC grinding machine for diagonal modified helical gear is proposed to reduce vibration and grinding errors. The deviations curve is designed and deviations surface of diagonal modified helical gear is fitted by 3 B-Spline based on tooth surface grid data established by the deviation curve. A Free-Form flank topographic correction method based on a six-axis CNC gear profile grinding machine with flat wheel is established according to principle of rack-cutter generated involutes gear and the kinematic relationships of the axes are derived based on equivalence of rack and flat wheel. An error correction model based on a sensitivity analysis is determined. Besides, each axis of the grinding machine are formulated as a six-degree polynomial and a disturbed polynomial coefficients on the topographic flank errors is developed by estimating whether the wheel contacts with the pinion. Using minimum squared error as the objective function, the particle swarm optimization algorithm are introduced to solve equations of the corrections, and the polynomial coefficients are ascertained, and this method of calculating results are stable and high precision. The result shows that slight variations in pressure angle, helix angle and generating angle along longitudinal tooth can get some specific diagonal modified tooth respectively, besides, diagonal modified tooth can then be efficiently ground by slightly adjusting six-axis movement according to the solved corrections and the validity of this method is numerically demonstrated using the six-axis CNC gear profile grinding machine, which effectively reduces grinding errors. The correctness of the theory and algorithm are supported by the sensitivity analysis of machine tool motion. © 2014 Journal of Mechanical Engineering
Wen J.,Harbin Engineering University |
Tan S.,Harbin Engineering University |
Fu X.,Harbin Engineering University |
Meng T.,Harbin Engineering University |
Song Y.,No.703 Research Institute of China Shipbuilding Industry Corporation
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2016
Experimental study of bubble velocity characteristics under sway motion is carried out. An experimental system is designed and manufactured. A fast camera is used to record the behavior of the bubbles. By tracking the path of the bubbles, movement parameters of the bubble are obtained under different motion conditions. It is found that the horizontal velocity, vertical velocity and path of bubbles are all obviously influenced by the inertial force and sloshing of free surface which are both induced by sway motion. The longer the sway motion period is, the greater the peak horizontal velocity is, and the sharper the path is and the shorter the vertical velocity is. Compared with inertial force, sloshing of free surface has a greater impact on the horizontal velocity. © 2016, Yuan Zi Neng Chuban She. All right reserved.
Yang M.,Harbin University of Science and Technology |
Wu L.,Harbin University of Science and Technology |
Shi H.,No. 703 Research Institute of China Shipbuilding Industry Corporation
Proceedings of 2013 2nd International Conference on Measurement, Information and Control, ICMIC 2013 | Year: 2013
In the application of some embedded systems such as the ship-borne routers, ATM machines and so on, many low-power embedded CPU needs connection with PCI-104 bus. However, these low-power embedded CPUs don't have the bus interface of PCI-104 (PCI). In order to solve this problem, this paper designs FPGA-based PCI-104 bus interfaces of the low-power embedded CPU. Through the analysis of PCI-104 bus protocol and the corresponding interface signal sequence, the method of Top-Down is applied to the modeling of the seven functional modules of PCI-104 bus interface such as the configuration register module, base address check module, state machine module, etc. Besides, in consideration that these CPUs can also be taken as the coprocessors, the master and target device interfaces of PCI-104 bus are programmed with the utilization of Verilog language, and the finite-state machine of the master device and the target device is structured in detail. Through the Modelsim simulation verification, it has been proved that the interface can meet the timing requirements of the PCI-104 bus specification, so as to connect these low-power embedded CPUs with PCI-104 bus expansion board. It also can realize to upgrade CPU on the PCI-104 bus board. © 2013 IEEE.
Yang M.,Harbin University of Science and Technology |
Zhao X.,Harbin University of Science and Technology |
Zhao S.,No. 703 Research Institute of China Shipbuilding Industry Corporation
Proceedings - 5th International Conference on Instrumentation and Measurement, Computer, Communication, and Control, IMCCC 2015 | Year: 2015
For the low accuracy of the spectrum sensing of the single node, this paper discusses several popular cooperative spectrum sensing technology. It also proposes a clustering double threshold cooperative spectrum sensing algorithm does two threshold detection based on the double threshold cooperative spectrum sensing algorithm. This algorithm applies or data fusion rule to realize the combination of the data among clusters on the basis of the improvement of the double threshold detection technology. The simulation results show that this algorithm can effectively reduce false alarm rate and undetected rate, and it can improve the overall detection performance. © 2015 IEEE.
Chen J.,Harbin University of Science and Technology |
Hu T.,No.703 Research Institute of China Shipbuilding Industry Corporation |
Li J.,Harbin University of Science and Technology
Applied Mechanics and Materials | Year: 2013
Flow behavior of gas and particles is predicted by the large eddy simulation of gas-second order moment of solid model (LES-SOM model) in the simulation of flow behavior in CFB. This study shows that the simulated solid volume fractions and velocity along height using a two-dimensional model are in agreement with experiments. The second-order moments of particles are computed. © (2013) Trans Tech Publications, Switzerland.