Optimization Study on a Single-cylinder Compressed Air Engine

The current research of compressed air engine（CAE） mainly focused on simulations and system integrations. However, energy efficiency and output torque of the CAE is limited, which restricts its application and popularization. In this paper, the working principles of CAE are briefly introduced. To set a foundation for the study on the optimization of the CAE, the basic mathematical model of working processes is set up. A pressure-compensated valve which can reduce the inertia force of the valve is proposed. To verify the mathematical model, the prototype with the newly designed pressure-compensated intake valve is built and the experiment is carried out, simulation and experimental results of the CAE are conducted, and pressures inside the cylinder and output torque of the CAE are obtained. Orthogonal design and grey relation analysis are utilized to optimize structural parameters. The experimental and optimized results show that, first of all, pressure inside the cylinder has the same changing tendency in both simulation curve and experimental curve. Secondly, the highest average output torque is obtained at the highest intake pressure and the lowest rotate speed. Thirdly, the optimization of the single-cylinder CAE can improve the working efficiency from an original 21.95% to 50.1%, an overall increase of 28.15%, and the average output torque increases also increases from 22.047 5 N · m to 22.439 N · m. This research designs a single-cylinder CAE with pressure-compensated intake valve, and proposes a structural parameters design method which improves the single-cylinder CAE performance.

Performance Comparisons of Five Different SPF Mouse Transport Containers

[Objectives]This study aimed at providing gist for selecting qualified transport containers by comparing the performance of common SPF mouse transport containers at home and abroad,and laying a foundation for subsequent improvement of transport containers.[Methods]In this study,5 different transport containers were selected,and their microbial filtration performance,ventilation,sterilization method and flux,and other related design and construction were analyzed.[Results]The results showed all 5 SPF mouse transport containers can provide enough air for the survival of mouse and protect them from bacterial infections.Transport container B and D are superior to others on one-time sterilization flux and deformation degree after autoclaving.Furthermore,taking into account the related design and construction of these transport containers,such as viewing window and carrying handle,the result of comprehensive comparison is that the transport container D>A>E>C>B.[Conclusions]In summary,the 5 SPF transport containers tested in this study can all satisfy the basic demand of SPF mouse transportation,but each transport container has its own advantages and disadvantages on storage space,deformation degree after autoclaving and other aspects.Thus,SPF mouse transport containers should be selected by different demand.