Experimental and numerical studies are carried out on a 6-cell tile-shaped aerospike nozzle, a 6-cell aerospike nozzle with round-to-rectangle primary nozzles and a 1-cell linear aerospike nozzle. Good altitude compen...Experimental and numerical studies are carried out on a 6-cell tile-shaped aerospike nozzle, a 6-cell aerospike nozzle with round-to-rectangle primary nozzles and a 1-cell linear aerospike nozzle. Good altitude compensation capacities and high efficiencies are obtained in the tests. The efficiencies of 6-cell tile-shaped aerospike nozzle and 1-cell linear aerospike nozzle at design altitude approach to 100 %, and that of 6-cell aerospike nozzle with round-to-rectangle primary nozzles in the same condition is about 95 % due to the imperfect cell contour and manufacturing defects. Numerical results are in good agreements with test data. The effects of ambient pressure on exhaust and then on base behavior are analyzed, The effects of variation in the amount of base bleed on performance are also examined in the tests.展开更多
基于某4缸带外部废气再循环(exhaust gas recycle,EGR)功能的自然吸气汽油机,采用1D热力学和3DCFD耦合仿真的方法研究了部分负荷工况各缸EGR分配的均匀性,并在性能台架上研究了EGR分配不均对各缸燃烧速度的影响。研究结果表明:缸内实际...基于某4缸带外部废气再循环(exhaust gas recycle,EGR)功能的自然吸气汽油机,采用1D热力学和3DCFD耦合仿真的方法研究了部分负荷工况各缸EGR分配的均匀性,并在性能台架上研究了EGR分配不均对各缸燃烧速度的影响。研究结果表明:缸内实际EGR均匀性不仅与EGR系统设计有关,同时也受到各缸进气的均匀性的影响;EGR的不合理分配会导致各缸燃烧速率不均,继而增大燃烧循环波动率。基于所建立的1D/3D耦合分析方法,对EGR分配孔板结构进行了详细仿真优化,EGR分配均匀性得到显著改善。在随后的试验中,各缸燃烧一致性明显改善。展开更多
文摘Experimental and numerical studies are carried out on a 6-cell tile-shaped aerospike nozzle, a 6-cell aerospike nozzle with round-to-rectangle primary nozzles and a 1-cell linear aerospike nozzle. Good altitude compensation capacities and high efficiencies are obtained in the tests. The efficiencies of 6-cell tile-shaped aerospike nozzle and 1-cell linear aerospike nozzle at design altitude approach to 100 %, and that of 6-cell aerospike nozzle with round-to-rectangle primary nozzles in the same condition is about 95 % due to the imperfect cell contour and manufacturing defects. Numerical results are in good agreements with test data. The effects of ambient pressure on exhaust and then on base behavior are analyzed, The effects of variation in the amount of base bleed on performance are also examined in the tests.
文摘基于某4缸带外部废气再循环(exhaust gas recycle,EGR)功能的自然吸气汽油机,采用1D热力学和3DCFD耦合仿真的方法研究了部分负荷工况各缸EGR分配的均匀性,并在性能台架上研究了EGR分配不均对各缸燃烧速度的影响。研究结果表明:缸内实际EGR均匀性不仅与EGR系统设计有关,同时也受到各缸进气的均匀性的影响;EGR的不合理分配会导致各缸燃烧速率不均,继而增大燃烧循环波动率。基于所建立的1D/3D耦合分析方法,对EGR分配孔板结构进行了详细仿真优化,EGR分配均匀性得到显著改善。在随后的试验中,各缸燃烧一致性明显改善。
