Numerical Investigation of Tandem-Impeller Designs for a Gas Turbine Compressor
Numerical Investigation of Tandem-Impeller Designs for a Gas Turbine Compressor
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DOI：
10.1115/1.1413472
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发表时间：
2001-06
影响因子：
1.7
通讯作者：
D. A. Roberts;S. C. Kacker
中科院分区：
文献类型：
--
作者：
D. A. Roberts;S. C. Kacker
串联叶片叶轮离心压缩机，它可以提供潜在的空气动力学效益超过传统的设计，很少采用在生产气体涡轮机应用。传统的叶轮设计通常是有利的，因为考虑到与串联配置相关的显著的性能损失和增加的制造成本。此外，许多关于串联叶轮特性的现有文献是不确定的，有时是矛盾的。由于串联叶轮的稀缺性，其设计规则几乎不存在。此外，诱导轮/诱导轮时序对串联叶轮性能和出口流动特性的影响还没有完全了解。在本研究中，进行了数值研究，以研究气体涡轮机压缩机（目标叶轮PR t-t 3.0）后级的串联叶轮设计的气动特性。为了探讨诱导轮/诱导轮同步对叶轮性能和出口流动品质的影响，对串列叶轮的诱导轮/诱导轮同步进行了参数研究。因为串联叶轮被设计成可针对现有的常规叶轮进行改造，所以还将其与基线常规设计的预测进行比较。研究结果表明，串联叶轮的效率低于传统的设计为所有的时钟配置研究。发现串列叶轮叶片时序对预测的压力比、温度比、效率和滑移系数有显著影响;这些参数的最大值预测用于直列串列配置。最小预测串联叶轮等熵效率发生在50%的时钟分数处，比直列情况低3.8个点。虽然串联叶轮的性能被预测为减少叶片时序增加，叶轮出口速度分布的均匀性显着改善进行了观察。叶轮出口处的总压和旋流分布表明，与传统设计相比，串联叶轮设计可以提供更好的扩压器恢复和失速裕度。
The tandem-bladed impeller centrifugal compressor, which may offer potential aerodynamic benefits over conventional designs, is rarely employed in production gas turbine applications. Conventional impeller designs are often favored because of concerns for both significant performance losses and increased manufacturing costs associated with tandem configurations. In addition, much of the available literature concerning the characteristics of tandem-impellers is inconclusive, and at times contradictory. Because of the scarcity of tandem-impellers, rules for their design are nearly nonexistent. Also, the effects of inducer/exducer clocking upon tandem-impeller performance and exit flow characteristics are not fully understood. In the present study, a numerical investigation was performed to investigate the aerodynamic characteristics of a tandem-impeller design for the rear stage of a gas turbine compressor (target impeller PR t-t 3.0). A parametric study of tandem-impeller inducer/exducer clocking was performed in order to explore its effect upon performance and exit flow quality. Because the tandem impeller was designed to be retrofittable for an existing conventional impeller, it was also compared to predictions for the baseline conventional design. Results of the study indicated that the tandem-impeller was less efficient than the conventional design for all clocking configurations studied. Tandem-impeller blade clocking was found to have a significant effect upon predicted pressure ratio, temperature ratio, efficiency, and slip factor; the maximum values for these parameters were predicted for the in-line tandem configuration. The minimum predicted tandem-impeller isentropic efficiency occurred at a clocking fraction of 50 percent, falling 3.8 points below that of the in-line case. Although the tandem-impeller performance was predicted to diminish as blade clocking was increased, significant improvements in the uniformity of impeller exit velocity profiles were observed. Profiles of both total pressure and swirl at impeller exit indicated that the tandem-impeller design may offer both improved diffuser recovery and stalling margin over the conventional design.