| Scroll compressors are widely used in refrigeration,air compression and other fields due to their small size,high reliability and stable operation.After nearly a century of development,the traditional oil-filled single-scroll scroll compressor can basically meet the needs of actual work.However,in some occasions where large displacement is required and the compressed air must be clean air,the traditional oil-filled single-scroll scroll compressor obviously cannot meet the needs.In view of the fact that it is difficult for the traditional oil-filled single-scroll scroll compressor to achieve the requirements of large displacement and oil-free compression at the same time,an oil-free double-scroll scroll compressor with a large displacement has been developed,and its mathematical model is established.In-depth study of thermal characteristics.The main research contents of this paper are as follows:(1)First,the profile equation of the scroll tooth of the double-wrap scroll compressor is given.From this,the geometric model of the scroll is established and the basic geometric parameters of the scroll tooth,the volume of the volume cavity and the exhaust after the tooth head are modified are derived.The calculation method of the angle;the value range of the starting angle of the vortex profile of the double scroll body that can be correctly meshed is analyzed under the condition of the base circle radius unchanged,and the influence of the occurrence angle and the base circle radius on the double scroll circle is discussed.The influence of the basic geometric parameters of the scroll compressor.(2)On the basis of the geometric model,combined with the first law of thermodynamics,the law of conservation of mass and the equation of state of gas,a thermodynamic model suitable for oil-free double scroll scroll compressors under actual working conditions is established.The model includes suction heating model,Heat transfer model and leakage model,and calculate the heat transfer area,leakage line length,power,efficiency and exhaust volume.(3)Compared with the single-scroll scroll compressor,the leakage process of the double-scroll scroll compressor is more complicated.In this paper,after an in-depth analysis and research on the leakage mechanism,the leakage process is modeled.The model is numerically solved,and the gas mass leakage through each leakage line changes with the rotation angle of the spindle,and the changes of the leakage and the pressure in the working chamber with the rotation speed and gap value of the spindle are analyzed.The 4th-order Runge-Kutta method is used to solve the established thermodynamic model,and the thermodynamic parameters of the compressed medium in the working cavity at any time of compression under the coupled action of heat transfer and leakage are obtained,and the thermodynamic parameters are compared with those in the working cavity under ideal conditions.The thermodynamic parameters of the compressed medium are compared and analyzed,and the influence of heat transfer and leakage on the thermodynamic parameters of the compressed medium in the working cavity is obtained.(4)An oil-free double-scroll scroll compressor performance test platform was built,and the discharge volume,discharge temperature and shaft power at different speeds and different discharge pressures were obtained through experimental measurements,and the measured experimental data and simulation values were carried out.By comparison,it is concluded that the established thermodynamic model can accurately reflect the working process of the oil-free double scroll scroll compressor.The thermodynamic model of the oil-free double scroll scroll compressor including heat transfer and leakage established in this paper can accurately simulate the working process of the oil-free double scroll scroll compressor under actual working conditions.It is an oil-free double scroll scroll compressor.The performance prediction of the rotary compressor provides a reference. |
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