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首页> 外文学位 >Effect of self recirculation casing treatment on the performance of a turbocharger centrifugal compressor.
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Effect of self recirculation casing treatment on the performance of a turbocharger centrifugal compressor.

机译：自循环套管处理对涡轮增压器离心压缩机性能的影响。

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摘要

Increase in emission regulations in the transport industry brings the need to have more efficient engines. A path followed by the automobile industry is to downsize the size of the internal combustion engine and increase the air density at the intake to keep the engine power when needed. Typically a centrifugal compressor is used to force the air into the engine, it can be powered from the engine shaft (superchargers) or extracting energy contained into the hot exhaust gases with a turbine (turbochargers). The flow range of the compressor needs to match the one of the engine. However compressors mass flow operating range is limited by choke on the high end and surge on the low end.;In order to extend the operation at low mass flow rates, the use of passive devices for turbocharger centrifugal compressors was explored since the late 80's. Hence, casing treatments including flow recirculation from the inducer part of the compressor have been shown to move the surge limit to lower flows. Yet, the working mechanisms are still not well understood and thus, to optimize the design of this by-pass system, it is necessary to determine the nature of the changes induced by the device both on the dynamic stability of the pressure delivery and on the flow at the inlet.;The compressor studied here features a self-recirculating casing treatment at the inlet. The recirculation passage could be blocked to carry a direct comparison between the cases with and without the flow feature. To grasp the effect on compressor stability, pressure measurements were taken in the different constituting elements of the compressor. The study of the mean pressure variations across the operating map showed that the tongue region is a limiting element. Dynamic pressure measurements revealed that the instabilities generated near the inducer when the recirculation is blocked increase the overall instability levels at the compressor outlet and propagating pressure waves starting at the tongue occurred, different in nature from rotating stall. The flow velocity was also measured at the inlet of the compressor by means of planar PIV measurements. The case without recirculation showed strong back flow occurrence at low MFR on the shroud of the inlet passage due to tip recirculation. With recirculation, this back flow was significantly reduced improving the overall stability. However, with the current recirculation channels design, there is an efficiency penalty and the recirculated flow introduces non-homogeneities in the mixing region.;Finally, to explore experimentally the effect of variations of the casing treatment, several different designs were tested. It was seen that modifications of the supporting rib shape impacted the efficiency. Also, improvements on the surge line were obtained with flow reinjection near the inducer in the direction of the main flow at low speeds and with induced counter swirl for all speeds.
机译：运输行业排放法规的增加带来了对更高效发动机的需求。汽车工业遵循的途径是减小内燃机的尺寸并增加进气口的空气密度，以在需要时保持发动机功率。通常，使用离心压缩机将空气压入发动机，它可以由发动机轴（增压器）提供动力，或通过涡轮机（涡轮增压器）提取包含在热废气中的能量。压缩机的流量范围需要匹配发动机之一。然而，压缩机的质量流量运行范围受到高端扼流圈和低端喘振的限制。为了扩大低质量流量的运行范围，自80年代末以来，人们一直在探索使用无源设备制造涡轮增压器离心式压缩机。因此，已经显示出包括从压缩机的进气口部分进行再循环的套管处理，可以将喘振极限移至较低的流速。然而，工作机制仍未得到很好的理解，因此，为了优化该旁路系统的设计，有必要在压力输送的动态稳定性和压力的变化方面确定设备引起的变化的性质。此处研究的压缩机在入口处具有自循环式套管处理功能。再循环通道可以被阻塞以在具有和不具有流动特征的情况之间进行直接比较。为了掌握对压缩机稳定性的影响，在压缩机的不同组成元件中进行了压力测量。对整个操作图上平均压力变化的研究表明，舌头区域是一个限制因素。动态压力测量显示，当再循环受阻时，在诱导器附近产生的不稳定性会增加压缩机出口处的整体不稳定性，并且会发生从舌头开始传播的压力波，这与旋转失速本质上有所不同。还通过平面PIV测量在压缩机的入口处测量了流速。没有再循环的情况显示，由于尖端再循环，在入口通道的护罩上以低MFR发生了强烈的回流。通过再循环，该回流明显减少，从而改善了整体稳定性。然而，在当前的再循环通道设计中，存在效率损失，并且再循环流在混合区域中引入了不均匀性。最后，为了实验地探索套管处理的变化的效果，测试了几种不同的设计。可以看出，改变支撑肋形状会影响效率。同样，通过在低速下沿主流动方向在诱导器附近重新注入气流，并在所有速度下均产生反向涡流，可以改善喘振线。

著录项

  • 作者

    Gancedo, Matthieu.;

  • 作者单位

    University of Cincinnati.;

  • 授予单位 University of Cincinnati.;
  • 学科 Aerospace engineering.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 250 p.
  • 总页数 250
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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