The Research On Dynamic Characteristics And Simulation Of Scroll Compressor

As a new high efficiency, low noise, positive displacement compressor, the scroll compressor has an irreplaceable advantage compared with other types of compressors and are widely used in refrigeration, air conditioning, power engineering and other fields. The area of application also been expanded by the development in the direction of the volume of the atmosphere and high power currently. With the development of science and technology, especially the development of petrochemical industry in recent years, scroll compressors in various sectors of the national economy become one of key equipments as the pressure is applied more broadly. With the improvement of computer development and manufacturing, more broad application area of scroll compressor development. Because of the structural characteristics of scroll compressor, its potential advantages have not been fully excavated. Therefore, investigation of scroll compressor with high quality is of great importance in practice. Funded by NSCF funding of "Study of coupling friction and dynamics in oil-free twin-wrap compressor" and "Investigation of friction and rotor dynamics performance in variable volume scroll compressor", the present work is aimed at developing geometrical model, leakage model and heat transfer and dynamic model based on the circle involute theory. Scroll compressor virtual prototype model has been obtained by using the three dimensional entity built die software. By analyzing the subsystem die state, crankshaft shell coupling dynamics of rotor, rotor balance characteristics and dynamic characteristics analysis considering kinematic pair clearance mechanism, a theoretical basis has been developed for reliability design and high performance of scroll compressor.First, the motion simulation for virtual prototype of scroll compressor was finished, including its solid models of parts, parts of the virtual Assembly and motion simulation of the machine and parts. By Building the solid models of parts, the positional relationship between the various parts have been described with considering the structural characteristics of scroll compressor under the physical prototype, then the relative spatial locations of the parts in a virtual environment has been determined, and virtual prototyping can be assembled. Check for the reasonable, reliable, relevant parts of movement coordination and whether there is interference in the campaign process of the scroll compressor design.Based on the scroll compressor virtual modeling, the dynamic characteristics of the scroll compressor rotor system were studied, the displacement and tilt of each node spindle system were analyzed according to the equations of motion units and rotor modal analysis theory; the dynamic coefficients of spindle bearings were obtained based on the rotor kinetic theory, and spindle bearings at two analytical models, a rigid support system and spring- damping system,were been established. The two scroll compressor rotor shaft models were analyzed under two conditions support system by using the finite element software, and obtained two vibration modes, the bearing stiffness impacted on its rotor dynamic characteristics also were analyzed at the spring-damper system.Using the finite element method and multi-body dynamics theory, the scroll compressor rotor and the shell modal were analyzed to obtain the natural frequency of the scroll compressor rotor and the frame and modes such as modal parameters. Based on multi-body models, the scroll compressor shaft topology configuration and flexible multi-body model of the spindle system were established. By analyzing the crankshaft system multi-body dynamics, the gas load and bearing loads under flexible body were obtained, and the dynamics of the frame in response to the problem under load were also analyzed.According to cut suffered crank pin radial force is about four times the size of the force,suffered through a balanced crank pin size of the average tangential force method to analyze the impact of the crank pin tangential force imbalance residual amount of spindle bearings; By analyzing the scroll compressor shaft and the shell, the force shaft housing and the torque balance equation were established, as design variables, the stress and load bearing spindle housing were used to analyze the impact of the counterweight mounting angle of the spindle bearing loads in the case that force under optimal conditions, to arrive at a balance of high quality and the phase angle and other parameters.Considering dimensional errors, clearance between turning pairs and wear gap exists, the scroll compressor cannot fully meet the ideal conditions for parallel four-bar, based on the virtual prototyping of scroll compressors, the rotor system of multi-body dynamics model and vector model of pairs with clearances with considering kinematic pair clearance were built, and the clearance model of contact-impact force and friction force model were embedded in ADAMS to carry out dynamics simulation. Simulation results can accurately predict the clearance between turning pairs on dynamic characteristics of scroll compressor, which provide reference and basis for the design of scroll compressors.By dynamic balance test and prototype performance test, verify the good performance and reliability of scroll compressor, the feasibility and necessity of dynamic balance test for high performance of scroll compressor of the research and development has laid a solid foundation.