Mutellip Ahmat

Nonlinear dynamics modeling and analysis of transmission error of wind turbine planetary gear system

In this paper, a type of planetary gear system in the wind turbine was studied by taking into account the actual conditions where the planetary gear system works. A nonlinear multi-gap planetary gear system finite element method model was established, and the engagement stress, the displacement, and the velocity curve with time of nodes of the planetary gear system were obtained by using explicit dynamic solution method. Under different speeds and different load, the variation of planetary gear system dynamic transmission error was then studied combined with the theory of gearing. The results showed that it is different from the dynamic transmission error of planetary gear system and planetary gear. Time-varying mesh stiffness of sun gear and the ring gear are also different along with their speed change. There are some correlation among time-varying mesh stiffness, meshing impact stress, and dynamic transmission errors. Therefore, it is suggested that the meshing stiffness and impact stress effect on the dynamic transmission error should be considered in the study of transmission error of wind turbine planetary gear system.

Experimental Analysis and Modeling of Thermal Error for the Spindle of Machining Center

In this paper, the spindle components of the TH635 0 Machining Center (MC) and its chief heat sources are analyzed, and the temperature field of th e MC and the thermal error of the spindle are measured. The temperature variation curve of the spindle system and the thermal displacement curves of the spindle are obtained. The thermal error model of the spindle is s t up by using the multivariable regression analy sis , and the model is analyzed and optimized by using the fu zzy cluster analysis (FCA) and the stepwise regress ion method(SRM). 1.Introduction Thermal error makes up 40~70% of the total error of mach ine tool [1]. So how to reduce the thermal error of machine tool has become concerning focus to manufactu ring industry in the world. For the indeterminacy of thermal boundaries and the complicated of heat t ransmission ,the research on thermal error of machi ne tool always remains in the qualitative stage. Now machin e manufacturing technology becomes more intelligent and efficient, develops at higher speed and accurac y, so thermal error is also received more attention tha any time before. Due to the rapid development of the co mputing and the error measurement technology, the modeling of the thermal error and the error compens ation have become possible [1,2,3,4,5]. The main purpose of this research is to measure the t mperature field of the MC and the thermal error of the spindle of the MC; to establish a functional re lation between the temperature field of the MC and the thermal error of the spindle by based on the experi mental data; to set up the thermal error model of t he spindle of the MC for base of the improving deign, the FEM analysis and the error compensation of the MC. The spindle is the primarily heat source and has a major effect to the precision of the MC, so the eff ct that heat of the spindle components produces to the prec ision of the MC is the focus of the research. In the study, an experimental system based on the v irtual instruments technology is presented,thirty-t wo thermocouple sensors are set on the spindle parts o f the MC to measure the thermal field of it, and fi ve electric vortex sensors are used to measure the the rmal rror of the spindle by five-point method. The thermal error model of th e spindle of the MC is set up by applying the multivariable regression ana lysis technology. Due to the altitudinal collinearity among the temperature variables, the FCA and the SRM are used to select the temperature variables in order to eliminate the effects of the collinearity to the model, and the e ff cts of the two methods are contrasted. 2.Experimental system design 2.1 Experimental object analysis Fig.1 shows the 3-D model of the TH6350 Machining C enter. Fig.1. The 3-D model of the MC Key Engineering Materials Online: 2003-07-15 ISSN: 1662-9795, Vols. 243-244, pp 177-182 doi:10.4028/www.scientific.net/KEM.243-244.177

Experimental Analysis and FEM Calculation of the Thermal Deformation for the Spindle System of Machining Center

In this study, the chief heat sources of the spindle system for the TH6350 Machining Center are analyzed, and an experimental system based on the virtual instruments technology is presented, thirty-two thermocouple sensors are set at the spindle system of the machining center to measure the thermal field, and five electric vortex sensors are used to measure the thermal error of the spindle by five-point method. The FEM modeling of the thermal deformation of the spindle system is built up by based of I-DEAS, the temperature field and the thermal deformation of it are calculated, and the calculated values of the model tallies with the experimental values.The researching results provide a theoretical foundation for the improving designtemperature controlling and the error compensation to the machining center.

Analysis of Carrying Capacity and Friction Torque of Friction Pair Fluid-Film for High Parameter Bellows Mechanical Seal

The friction pair for bellows mechanical seal as a friction element is one of the key components for it. In this research, by based on the computational fluid dynamics (CFD) numerical theory, using the Fluent software, corresponding model and parameters, the fluid-film between the clearance of the sealing ring friction pair for the bellows mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions is numerically simulated, the relationship between the carrying-capacity of the fluid-film and the temperature, the viscosity of the fluid-film, the relationship between friction torque of the fluid-film and the speed, viscosity of the fluid-film, the influence factor of leakage are obtained. The researching results provide the scientific basis for the optimization designing of the high parameter bellows mechanical seals.

Two-phase Flow Field Characteristics Analysis on Seal Cavity for Bellows Mechanical Seal under Variable Operating Conditions

This research based on the vapor-liquid two-phases flow theory and methods, by using the CFD mix-multiphase flow model, the seal cavity vapor-liquid two-phases flow field for the bellows cartridge mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions was numerically simulated and analyzed, then the characteristics of the complex three-dimensional flow field of seal cavity caused by the rotation of the sealing ring were obtained by the different position of the injected coolant, and the different cooling effects were contrasted, then the best cooling position were found by analysis. The researching results provide a theoretical basis for the structural optimization design of the high parameters bellows cartridge mechanical seal devices.

Analysis of the Pressure and Carrying Capacity of the Friction Pair Fluid-Film for the High Parameter Bellows Mechanical Seal

In this research, by based on the computational fluid dynamics (CFD) numerical theory, using the Standard-Turbulence model and the Standard-Wall function, the fluid-film between the clearance of the sealing ring friction pair for the bellows mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions was numerically simulated, the pressure fluid and the relationship of the carrying-capacity of the fluid-film between the pressure inlet of seal cavity and the width of the fluid-film, and the results of the numerical analysis was compared with the theoretical value. The researching results provide the scientific basis for the optimization designing of the high parameter bellows mechanical seals.

The Parametric Modeling and Contact Strength Analysis for the Wind Power Increasing Gear

In this paper, the precise 3D model of the wind power increasing gear was set up by based on the parametric designing method of Pro/Program, then the contact strength of the gear was analyzed by the FEM and the Hertz theoretical value was calculated, the FEM and the Hertz results were contrasted in order to confirm the applicability of the numerical analysis in wind power gear contact analysis. Finally, the corresponding analysis conclusion was received.The researching results offered a effective theoretical basis for the optimization design and analysis of the wind increasing gear.

Experimental Test and Numerical Simulation of Torsional Strength for Welded Metal Bellows

In this research, the numerical simulation of torsional strength for single and double layer of high parameter welded metal bellows mechanical seal is carried out and the stress-strain diagram is obtained. Besides, the torsional strength is tested by experiment and the result of it is compared with the simulating results, and the feasibility and availability of numerical simulation have been proved. The result provides a guide for the structural optimization and the calculation of torsional fatigue failure of welded metal bellows.

Contact Analysis of Sealing Rings for Welding Bellows Mechanical Seal

In this research, the FEM models of sealing rings for welding bellows mechanical seals were established by applying both isolation and integral contact method, and the displacement and stress of sealing ring’s were calculated. The result shows that a wedge-shaped was appeared on the seal face under the medium pressure and spring force. It can be seen that the integral contact analysis effectively illustrated that the convergence and divergence of the wedge-shaped deformation will be occurred in the contact face. The researching results provide a theoretical basis for the furthermore analysis of the deformation and frictional wear and structure optimization of sealing rings for welding bellows mechanical seal.

Study on the Field Dynamics of the Seal Cavity Flow Field for High Parameters Bellows Mechanical Seal

Based on the computational fluid dynamics (CFD) theory and numerical simulation methods, the seal cavity flow field for the bellows mechanical seal under such the high temperature, high pressure, high-speed as complex working conditions was numerically simulated, and the temperature field, velocity field, pressure field, turbulent kinetic energy and the flow field vorticity distribution of the medium of the seal cavity were obtained, the three-dimensional fluid flow in the seal cavity, the heat transfer characteristics and the impact on the sealing performance were analyzed in this researching.