Geometry of Screw Compressor Rotors and Their Tools
Screw compressor is a common type of machine used to compress gases.It consists of a pair of meshing rotors with helical grooves machined in them contained in a casing,which fits closely round them.The rotors and casing are separated by very small clearances.The rotors mesh like gears in such a manner that as they rotate the space formed between them and the casing is reduced progressively.Thus any gas trapped in this space is compressed.Although the principles of operation of helical screw compressors have been well known for more than 120 years,it is only during the past 40 years that they have become widely used.The main reasons for that were their poor efficiency and the high cost of manufacturing their rotors.Two main developments led to a solution to these difficulties.The first was the introduction of the asymmetric rotor profile approximately 35 years ago which substantially reduced the blow-hole area,which was the main source of internal leakage,and thereby raised the thermodynamic efficiency of these machines to roughly the same level as that of traditional reciprocating compressors.The second was the introduction of precise thread milling machine tools at approximately the same time which made it possible to manufacture accurately and economically items of complex shape,such as the rotors.From then on,as a result of their ever improving efficiencies,high reliability and compact form,screw compressors have taken an increasing share of the compressor market,especially in the fields of compressed air production,and refrigeration and air conditioning,and today,a good proportion of compressors manufactured for industry are of this type.This paper presents a method of general geometrical definition of screw machine rotors and its manufacturing tools.It describes the details of lobe shape specification and focuses on a new lobe profile which yields a larger cross-sectional area and shorter sealing lines resulting in higher delivery rates for the same tip speed.A well proven mathematical model was used to determine its optimum profile,size and the volume ratio and compressor ports to achieve the superior compressors.
Geometry of screw compressors Rotor lobe profile Cutting tools
Nikola Stosic Ian K Smith Ahmed Kovacevic Elvedin Mujic
Centre for Positive Displacement Compressors City University London,Northampton Square,London EC1V 0 Centre for Positive Displacement CompressorsCity University London,Northampton Square,London EC1V 0H
国际会议
第六届压缩机与制冷国际会议(The 6th International Conference on Compressor and Refrigeration(ICCR))
西安
英文
2-27
2008-09-25（万方平台首次上网日期，不代表论文的发表时间）