Research On Lean Design And Its Application In Large Centrifugal Compressor Units

With the rapid development of modern industry, Large-capacity, efficient operation, structure complication, energy saving and noise reduction becomes inevitable trend of large scale compressor development. How to develop super large compressor with indigenous intellectual property rights and meet the demands of upgrade quality and product creativity with the guidance of scientific development view. When the demand of the nation’s economy and the people’s livelihood is ensured, how to decrease research-and-development cost, reducing product development cycles, improve development efficiency will become key problems in large scale compressor manufacturing.The dissertation studies implementation methods of modern design theory based on synthesis design theory created by professor Wen Bangchun in large scale complicated products. By making quality and benefit as objectives, lean technology as foundation and super-large compressor as research object, adopting nonlinear dynamics, structural mechanics, reliability and nonlinear aerodynamics, making development cost as constraint conditions, a lean design implementation method is presented based on system engineering thinking.High-level viewable optimization design method is put forward in the process of studying this method. Evaluation index and operation method of screening method of design object are determined. Lean filtration and high-level dynamic optimization method and high-level viewable optimization method are introduced. And aerodynamic performance analysis, technological properties, working performance and optimization design of impeller components assembly structure and combination property and optimization design of rotor system are performed in main function domain, auxiliary function domain and coupling domain of both. The main research contents are as follows:(1) Lean design concept is put forward by learning from successful experience of lean in product system. The detail meanings of "fine" and "benefit" of lean design are explained and basic frameworks of lean design are determined.(2) Implementation method of a complete super large compressor lean design is offered based on synthesis design theory. General planning, function deployment of whole unit, lean design in main and auxiliary function domains and coupling domain of both are carried out in the design process of super large compressor. Lean design tools are selected based on synthesis design theory and lean thinking in detail. Lean design implementation method considering cost control is presented when design, optimization and evaluation of product key systems and structures are fulfilled.(3) Four implementation tools for lean design are constructed in the process of studying the implementation method when design quality is improved and cost is controlled. These tools are as follows:function decomposition tool for system, lean screening tool of design object for reducing development cost, high-level dynamic tool and viewable tool for improving product design quality. These constructed tools include as follows:①8D overall plan model and its implementation framework are determined;②The concept of high-level viewable optimization method and its application method are presented;③Application scope of high-level dynamic optimization method is extended;④Lean design screening method is formed by constructing two evaluation indexes of quality contribute rate and cost influence ratio.(4) In the process of lean design in main function domain, firstly, adding-gas system is determined as the most important research object by design object lean screening. And aerodynamic performance research and conceptualization design work are performed by using high-level viewable design tool. Design defects of the former adding-gas structure are discovered and a new adding-gas structure with inlet turbine casing is presented by analysis of many kinds of pneumatic components and adding-gas structure. In the checkup process of design quality, firstly, evaluation works about the adding-gas structure affecting on surrounding pneumatic components is completed after computational fluid dynamics of whole channel model of (including adding-gas structure and its adjacent two module levels) is analyzed by mean of high performance computing platform.(5) In the lean design process of auxiliary function domain, making as objective and combining high-level dynamic optimization design method and high-level viewable optimization design method, key structure creation and detailed design method are completed. And CAX integrated environment is constructed on the basis of above method. By combining nonlinear contact theory and structure dynamic theory, technological property of impeller assembly structure and structure performance at operating condition are completed. Then the initial design proposal of new impeller hub is presented by using viewable optimization method. Technological property and structure performance optimization are performed by using high-level dynamic optimization design method. Finally, combining stochastic finite element method and nonlinear reliability method, reliability of initial and improved structures are computed and function effect on both is discussed for different random parameters. (6) In the lean design process of rotor system, detailed operation method and implementation flow for improving design quality are completed by using high-level dynamic optimization tools. Starting with system function analysis, synthesis performance optimization, trial run and working performance forecast, synthesis performance analysis, initial scheme determination and final structure detail design work of super large compressor rotor system are completed. The dynamic characteristics of every single cylinder and whole series rotor system are studied. Evaluation work is performed for lean design method by using trail run of prototype and forecast method of nonlinear transient dynamic for working performance.