Characteristics of turbocharger.
Characteristics of turbocharger.
Turbocharger, that is, the engine intake supercharger, compresses the air before entering the engine cylinder through the supercharger to improve the air density, so that more air is filled into the cylinder, thereby increasing the engine power. The engine equipped with turbocharger can not only output larger takeoff power, but also improve the altitude characteristics of the engine.
For a long time, China's marine turbocharger turbine technology has mainly relied on technology introduction and imitation manufacturing. The market share of domestic products is not large. The domestic marine turbocharger market is basically monopolized by foreign turbocharger companies such as abb. With the further implementation of emission regulations, there is an urgent need for domestic supercharger products to meet the supercharging matching needs of diesel engine manufacturers after developing new products, and to break the unfavorable situation that the marine diesel engine supercharger market is monopolized by foreign brands.
According to the supercharging matching requirements of medium and low-speed marine diesel engines, the use environment and process manufacturing problems, the technology development unit has promoted the turbocharger turbine technology for heavy vehicles to the marine field, and can develop a new generation of turbocharger that is equivalent to the current international advanced products and meets the emission requirements of IMO phase III.
Key technology breakthrough.
(1) Matching characteristic analysis of marine diesel engine turbocharger
The working process model of marine environmental diesel engine is established, and the influence of the performance of marine engine and the performance change of supercharging system is analyzed; Establish a three-dimensional model of the supercharged intake and exhaust system, and use one / three-dimensional coupling simulation to study the mechanism of three-dimensional flow coupling effect on the matching of various components, which lays a foundation for the design of high-performance marine superchargers.
(2) Optimization analysis of compressor performance.
Use conceptsnrec software to carry out the preliminary design of the compressor impeller, diffuser and volute. Use one-dimensional and quasi three-dimensional flow analysis technology to preliminarily analyze the speed and pressure distribution of the compressor, adjust the modeling law, and meet the reasonable gas flow parameter distribution. The three-dimensional transonic flow analysis method of the compressor is used to carry out the full three-dimensional CFD calculation of the impeller, diffuser and volute under all working conditions, optimize the geometric structure, reduce the flow loss, improve the aerodynamic performance of the compressor and the optimal matching of the full working condition range.
The problem that the flow range in the high pressure ratio working area is too narrow is solved by flow control, and the performance of the compressor is improved by matching and performance optimization of the vaned diffuser. Through the strength calculation and reliability analysis of the compressor impeller, the structural optimization design is carried out to reduce the weight on the premise of meeting the reliability requirements.
(3) Manufacturing process analysis of key parts.
On the basis of the original process plan, the compressor impeller milling mainly uses CAD / CAM technology to carry out computer three-dimensional modeling, overall milling process analysis and research, five axis NC programming and three coordinate measurement verification; Further optimize the machining process, solve the problems of tool and workpiece vibration and complex surface machining error in the machining process, improve the machining accuracy and shorten the machining time.
Aiming at the casting process of superalloy materials for turbocharger turbine, combined with the research results of existing superalloy materials, the solidification process and the detection of crystal structure are analyzed and studied, and the effects of part structure, chemical composition, cooling rate, liquid phase temperature and so on on on the solidification process and crystal structure are found, so as to more accurately grasp the solidification front state and crystal structure state. Determine the turbine casting tooling system and process parameters, and control the solidification mode of the casting to obtain the grain growth orientation and distribution required by the process.
