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作为旨在改进251柴油机用增压器性能和可靠性的整个研制计划的一部分,人们已经确认,采用水冷式铸钢进气壳是涡轮性能不好的主要因素,其主要原因是气流在其通道中有很大的变形。通过将涡轮的原始性能参数与指标值或参考值进行比较后,便可确定出这类变形所产生的影响。所谓指标值或参考值(a traget or refenrence level)是通过在喷嘴环入口使具有理想的流动状态而得到的。喷嘴环入口处的理想流动状态是通过采用一个大的环形气道代替涡轮进气壳而实现的。比较结果表明,涡轮效率和通流能力的显著降低是由于涡轮进气壳引起的。我们制作了一个新的试验型无水冷涡轮进气壳。这是一种简单而轻便的钢板结构进气壳,为了降低进气流的不均匀度,对燃气流道进行了改进。所有试验结果都与涡轮效率的指标值和参考值进行了比较。涡轮效率损失从9.5%减少到3.5%。在柴油机上的初步试验表明,满负荷时,油耗降低了1.0%～1.5%。
As part of an overall development plan to improve the performance and reliability of the 251 diesel supercharger, it has been confirmed that the use of water-cooled cast steel intake housings is a major contributor to poor turbine performance due to the air flow in its passage In the great deformation. By comparing the original performance parameters of a turbine with an indicator or reference value, the effect of such deformation can be determined. The so-called index value or reference value (a traget or refenrence level) is obtained through the nozzle ring inlet with a desired flow state. The ideal flow condition at the nozzle ring inlet is achieved by using a large annular air passage instead of the turbine inlet shell. The comparison shows that the significant reduction in turbine efficiency and flow capacity is due to the turbine inlet shell. We made a new pilot-type, water-cooled turbine inlet shell. This is a simple and lightweight steel structure intake housing, in order to reduce the intake flow unevenness, the gas flow channel has been improved. All test results are compared with turbine efficiency indicator values and reference values. Turbine efficiency loss decreased from 9.5% to 3.5%. Preliminary tests on diesel engines show that at full load, fuel consumption is reduced by 1.0% to 1.5%.