Microengines are regarded as the potential replacements for batteries.Aimed at the unsatisfactory thermal property of silicon used in the combustion chambers,ceramics are chosen as the construction material in this pa...Microengines are regarded as the potential replacements for batteries.Aimed at the unsatisfactory thermal property of silicon used in the combustion chambers,ceramics are chosen as the construction material in this paper.The fabrication process where alumina has been chosen as the microengine material is discussed.Vigorous FEA has been carried out,and it is found that the material satisfies the stress and deformation requirements of the design.Then the alumina fabrication process is described.Soft reusable polydimethylsiloxane(PDMS)moulds are produced from SU-8 resist masters,and alumina microengine parts are produced using the PDMS moulds.Images of the ceramic components show that the fabrication satisfies the design requirements.展开更多
This paper presents an application of global sensitivity analysis for system safety analysis of reciprocating aircraft engine. Compared with local sensitivity analysis results, global sensitivity analysis could provid...This paper presents an application of global sensitivity analysis for system safety analysis of reciprocating aircraft engine. Compared with local sensitivity analysis results, global sensitivity analysis could provide more information on parameter inter- actions, which are significant in complex system safety analysis. First, a deterministic aviation reciprocating engine thermody- namics model is developed and parameters of interest are defined as random variables. Then, samples are generated by Monte Carlo method for the parameters used in engine model on the basis of definition of factor distribution. Eventually, results from engine model are generated and importance indices are calculated. Based on the analysis results, design is improved to satisfy the airworthiness requirements. The results reveal that by using global sensitivity analysis, the parameters could be ranked with respect to their importance, including first order indices and total sensitivity indices. By reducing the uncertainty of parameters and adjusting the range of inputs, safety criteria would be satisfied.展开更多
The dominant feature of the work of many specialists on the design of the internal combustion engine is to achieve the possible lowest fuel consumption, which is the most convenient measure of the efficiency of the th...The dominant feature of the work of many specialists on the design of the internal combustion engine is to achieve the possible lowest fuel consumption, which is the most convenient measure of the efficiency of the thermodynamic cycle. From the very beginning of this heat machine, there are many of solutions that are better or worse fit to the global development trend. In this paper, the authors suggest the possibility closer to the optimal solution by introducing structural active zones, where the task is instantaneous(during one cycle) heat transfer to the skin layer on elements of the combustion chamber and to transfer part of the recovered heat to the next cycle, reaching a growth effect of the useful efficiency by 10% to 20%. The solution is different from the ones used by the fact that it is only partially insulating barrier, and the main goal is focused on supporting the next thermal cycle by which it is possible to affect as mentioned above. This paper describes the idea of the functioning of the active combustion chamber and pointed out the technical capabilities of its creation.展开更多
基金Sponsored by the Natural Science Foundation of Heilongjiang Province (Grant No.E2004-06)
文摘Microengines are regarded as the potential replacements for batteries.Aimed at the unsatisfactory thermal property of silicon used in the combustion chambers,ceramics are chosen as the construction material in this paper.The fabrication process where alumina has been chosen as the microengine material is discussed.Vigorous FEA has been carried out,and it is found that the material satisfies the stress and deformation requirements of the design.Then the alumina fabrication process is described.Soft reusable polydimethylsiloxane(PDMS)moulds are produced from SU-8 resist masters,and alumina microengine parts are produced using the PDMS moulds.Images of the ceramic components show that the fabrication satisfies the design requirements.
基金Innovation Plan of Aero Engine Complex System Safety by the Ministry of Education Chang Jiang Scholars of China (IRT0905)
文摘This paper presents an application of global sensitivity analysis for system safety analysis of reciprocating aircraft engine. Compared with local sensitivity analysis results, global sensitivity analysis could provide more information on parameter inter- actions, which are significant in complex system safety analysis. First, a deterministic aviation reciprocating engine thermody- namics model is developed and parameters of interest are defined as random variables. Then, samples are generated by Monte Carlo method for the parameters used in engine model on the basis of definition of factor distribution. Eventually, results from engine model are generated and importance indices are calculated. Based on the analysis results, design is improved to satisfy the airworthiness requirements. The results reveal that by using global sensitivity analysis, the parameters could be ranked with respect to their importance, including first order indices and total sensitivity indices. By reducing the uncertainty of parameters and adjusting the range of inputs, safety criteria would be satisfied.
文摘The dominant feature of the work of many specialists on the design of the internal combustion engine is to achieve the possible lowest fuel consumption, which is the most convenient measure of the efficiency of the thermodynamic cycle. From the very beginning of this heat machine, there are many of solutions that are better or worse fit to the global development trend. In this paper, the authors suggest the possibility closer to the optimal solution by introducing structural active zones, where the task is instantaneous(during one cycle) heat transfer to the skin layer on elements of the combustion chamber and to transfer part of the recovered heat to the next cycle, reaching a growth effect of the useful efficiency by 10% to 20%. The solution is different from the ones used by the fact that it is only partially insulating barrier, and the main goal is focused on supporting the next thermal cycle by which it is possible to affect as mentioned above. This paper describes the idea of the functioning of the active combustion chamber and pointed out the technical capabilities of its creation.
