闭式离心压缩机几何建模对数值预测结果的影响

发布时间：2018-01-08 01:02

本文关键词：闭式离心压缩机几何建模对数值预测结果的影响　出处：《中国科学:技术科学》2017年06期 　论文类型：期刊论文

【摘要】：实验测试了一台闭式离心压缩机的整体性能,采用部件叠加的方法构造了不同的压缩机数值模型,研究了闭式离心压缩机堵塞流量及数值预测准确性的影响因素,提出并验证了采用等效叶片厚度替代叶片端壁圆角的压缩机结构修正方法.本研究的主要目的在于评估各种细微几何结构和简化处理对具有闭式叶轮的离心压缩机总体性能的影响,以此归纳出针对闭式离心压缩机合理的数值模拟策略.实验测得压缩机峰值等熵效率为80.28%,经等效叶片厚度修正后压缩机数值模拟所得等熵效率峰值为82.02%.研究结果表明轮盖间隙及其密封、叶片端壁圆角以及叶片加工误差是影响闭式离心压缩机性能的3个主要几何结构因素.闭式叶轮轮盖间隙泄漏流减小了叶轮的有效喉部面积,使堵塞流量减小,流道中部流体加速,叶轮扩压能力下降;一定的背压下,闭式叶轮的堵塞流量随叶片相对厚度的增加呈线性关系减小.在数值模拟时,采用等效叶片厚度修正闭式压缩机端壁圆角,可以使压缩机在保持小流量工况性能基本不变的同时,提高大流量工况的数值模拟准确性.
[Abstract]:The whole performance of a closed centrifugal compressor is tested experimentally. Different numerical models of compressor are constructed by means of superposition of components. The factors influencing the clogging flow rate and the accuracy of numerical prediction of closed centrifugal compressor are studied. This paper presents and verifies the modification method of compressor structure by using equivalent blade thickness instead of end wall circular angle of blade. The main purpose of this study is to evaluate various fine geometry structures and simplify centrifugal compression with closed impellers. The impact of the overall performance of the machine. A reasonable numerical simulation strategy for the closed centrifugal compressor is concluded. The experimental results show that the peak Isentropic efficiency of the compressor is 80.28%. The isentropic efficiency peak value of the compressor is 82.02 after the equivalent blade thickness is corrected. The results show that the clearance of the wheel cover and its seal. The angle of the end wall of the blade and the machining error of the blade are the three main geometric structure factors which affect the performance of the closed centrifugal compressor. The leakage flow of the clearance of the closed impeller cover reduces the effective throat area of the impeller and the blocked flow rate. In the middle of the passage, the fluid accelerates and the diffusing capacity of the impeller decreases. Under certain back pressure, the clogging flow of closed impeller decreases linearly with the increase of blade relative thickness. In numerical simulation, the end wall corner of closed compressor is modified by equivalent blade thickness. The compressor can keep the performance of small flow condition unchanged and improve the accuracy of numerical simulation of large flow condition.
【作者单位】：西安交通大学能源与动力工程学院流体机械及压缩机国家工程研究中心;
【基金】：国家自然科学基金(编号:51236006)资助项目
【分类号】：TH452
【正文快照】： 1引言随着计算流体力学(computational fluid dynamics,CFD)和高性能计算机的发展,对压缩机/压气机性能进行精确地数值预测成为可能.过去对压缩机的数值模拟,综合考虑时间成本、建模和计算收敛难度等因素,常常忽略或者简化了密封、叶片与盘盖制造中形成的圆角、盖盘侧空腔等细

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