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为了探讨离心压气机性能随雷诺数的变化规律,对带蜗壳的全周流道流场进行数值模拟,分析雷诺数对内部流场结构的影响。结果表明:压气机工作于Re=5.7×104和Re=1.3×104下的最高效率比Re=1.4×105分别下降了4.5%和8.5%,所有工况在10%叶高附近效率最高。受到蜗壳的影响,全周流道计算所得压气机的效率值和工作范围均小于单流道计算结果。低雷诺数时,气流抗逆压梯度能力迅速减弱,叶顶泄漏流向下游发展过程中,会绕过相邻叶片前缘或顶部间隙进入其他流道;叶片表面约化静压沿径向的梯度增加,从而造成更严重的二次流动;前缘激波强度、附面层厚度和尾迹宽度均增加,流道内出现激波,压气机性能严重恶化。
In order to investigate the variation of centrifugal compressor performance with the Reynolds number, the numerical simulation of the flow field around a full-circle flow channel with a volute is carried out to analyze the effect of Reynolds number on the internal flow field structure. The results show that the maximum efficiency of compressor operating at Re = 5.7 × 104 and Re = 1.3 × 104 is 4.5% and 8.5% lower than that of Re = 1.4 × 105, respectively. The efficiency of compressor is the highest at 10% leaf height. Affected by the volute, the efficiency value and working range of the compressor calculated by the full-circle runner are all smaller than those calculated by the single runner. When the Reynolds number is low, the ability of the airflow to resist the adverse pressure gradient decreases rapidly. During the development of the tip leakage flow to the downstream, it will bypass the leading edge of the adjacent blade or the top clearance to enter other flow paths. The blade surface reduces the radial gradient along the radial direction Which leads to a more serious secondary flow. The strength of the front shock wave, the thickness of the overlay and the width of the wake increase. The shock wave appears in the flow channel and the performance of the compressor deteriorates seriously.