The rotating disk cavity is an important part of the cooling-air system of the aero engine,and it has obviously significance to study the internal flow and heat transfer characteristics of the disc cavity,which will b...The rotating disk cavity is an important part of the cooling-air system of the aero engine,and it has obviously significance to study the internal flow and heat transfer characteristics of the disc cavity,which will be helpful to improve the efficiency of the aero engine.This paper summarizes the existing research results of domestic and overseas.The present work considers the test methods and calculation methods of the flow and heat transfer characteristics of the rotating disc cavity of the aircraft engine.It points out that,the main factors which affect the heat transfer characteristics are the disc chamber speed,the intake volume,the design of the disc cavity pre-rotation/despin structure,and the type of disc cavity system.The influence of these factors on the characteristics of flow heat transfer is summarized.Based on these factors,the disc cavity structure can be optimized and designed,which provides suggestions for reducing the weight of the turbine,improving the thrust-to-weight ratio of the aero engine,and improving the cooling efficiency.展开更多
The construction of shield tunneling method, there are often phenomena such as tool wear, breakage and collapse of shield tunneling machine, which lead to downtime and affect the construction period. In this paper, ba...The construction of shield tunneling method, there are often phenomena such as tool wear, breakage and collapse of shield tunneling machine, which lead to downtime and affect the construction period. In this paper, based on the actual situation of two large diameter mud and water shield tunneling machine entering the warehouse and changing the tool, the amount of tool wear is counted, calculated, analyzed and optimized design. Conclusion: 1. the rationality of tool alloy height;2. the importance of cutting tool layering and reasonable arrangement;3. increase the number of tools on the same track as much as possible;4. the wear limit of the tool is reasonably determined by calculation to provide theoretical support for the frequency and reasonable tool change time of warehousing;5. reasonable arrangement of cutter head tool to avoid the phenomenon of tool waste.展开更多
文摘The rotating disk cavity is an important part of the cooling-air system of the aero engine,and it has obviously significance to study the internal flow and heat transfer characteristics of the disc cavity,which will be helpful to improve the efficiency of the aero engine.This paper summarizes the existing research results of domestic and overseas.The present work considers the test methods and calculation methods of the flow and heat transfer characteristics of the rotating disc cavity of the aircraft engine.It points out that,the main factors which affect the heat transfer characteristics are the disc chamber speed,the intake volume,the design of the disc cavity pre-rotation/despin structure,and the type of disc cavity system.The influence of these factors on the characteristics of flow heat transfer is summarized.Based on these factors,the disc cavity structure can be optimized and designed,which provides suggestions for reducing the weight of the turbine,improving the thrust-to-weight ratio of the aero engine,and improving the cooling efficiency.
文摘The construction of shield tunneling method, there are often phenomena such as tool wear, breakage and collapse of shield tunneling machine, which lead to downtime and affect the construction period. In this paper, based on the actual situation of two large diameter mud and water shield tunneling machine entering the warehouse and changing the tool, the amount of tool wear is counted, calculated, analyzed and optimized design. Conclusion: 1. the rationality of tool alloy height;2. the importance of cutting tool layering and reasonable arrangement;3. increase the number of tools on the same track as much as possible;4. the wear limit of the tool is reasonably determined by calculation to provide theoretical support for the frequency and reasonable tool change time of warehousing;5. reasonable arrangement of cutter head tool to avoid the phenomenon of tool waste.
