离心叶轮变工况气动性能计算及CFD验证

发布时间：2018-03-20 10:11

本文选题：离心压缩机　切入点：变工况　出处：《天津大学》2012年硕士论文　论文类型：学位论文

【摘要】：在离心压缩机基本级的损失预估过程中,应较全面考虑叶轮、扩压器等各个元件中的所有流动损失,并建立损失模型,如:叶片表面摩擦损失、叶片载荷损失、间隙损失、尾迹混流损失、回流损失以及扩压器内流动损失等。本文在已有的离心压缩机变工况性能预测基础上,建立贴近真实情况的损失模型,选择贴近真实情况的修正参数计算公式,运用FORTRAN语言和VISUAL BASIC语言编写程序进行离心叶轮变工况气动性能计算处理。运用已有的离心压缩机最佳工况点的数据参数作为变工况程序的初始值,给定变转速的数值及个数,得到变转速变流量条件下的气动参数值,最终得到某转速下的性能曲线,程序还可以预测喘振与阻塞现象发生点,为压缩机的安全运行提供保障。采用Eckardt经典叶轮进行离心压缩机变工况性能预测程序的准确性验证。运用计算软件,生成叶轮和无叶扩压器几何模型,计算得到变工况条件下的性能参数等值,然后运行本文编制程序,得到变工况条件下的性能参数及气动性能曲线。通过对比两者变工况条件下的整机效率、叶轮效率以及压比等参数,分析预测值与实验值之间的误差程度与影响原因。由于目前离心压缩机性能预测方法主要采用由实验结果归纳得到的关系式,不可避免造成性能预测数据与真实值之间一定范围内的差距。本文变工况计算程序也是一个需要不断验证的过程,需要结合更多更丰富的数值与实验结果不断完善计算方法与修正参数。本文意义在于在设计阶段基本了解压缩机的性能情况,在离心压缩机的总体设计中缩短设计的周期,提高设计的效率。
[Abstract]:In the process of estimating the loss of basic stage of centrifugal compressor, all flow losses in impeller, diffuser and other components should be considered comprehensively, and a loss model should be established, such as: loss of friction on blade surface, loss of load on blade, loss of clearance, etc. Wake mixed flow loss, reflux loss and flow loss in diffuser. On the basis of the performance prediction of centrifugal compressor under different working conditions, this paper establishes a loss model close to the real situation, and selects the formula for calculating the modified parameters close to the real situation. The FORTRAN and VISUAL BASIC programs are used to calculate and process the aerodynamic performance of centrifugal impeller under different working conditions. The data parameters of the best working point of centrifugal compressor are used as the initial value of the program, and the value and number of variable speed are given. The aerodynamic parameters under the condition of variable rotational speed and variable flow rate are obtained, and the performance curve at a certain speed is obtained. The program can also predict the occurrence point of surge and blockage, which provides a guarantee for the safe operation of the compressor. The Eckardt classic impeller is used to verify the accuracy of the program for predicting the performance of centrifugal compressor under different working conditions. The geometric model of impeller and vaneless diffuser is generated by using the calculation software, and the equivalent of performance parameters under the condition of variable working condition is obtained. Then run the program in this paper to get the performance parameters and aerodynamic performance curves under the condition of variable working conditions. By comparing the whole machine efficiency, the impeller efficiency and the pressure ratio, etc. The degree of error between the predicted value and the experimental value and the cause of its influence are analyzed. As the current centrifugal compressor performance prediction methods are mainly based on the experimental results summarized from the relationship, It is inevitable to cause the gap between the performance prediction data and the real value in a certain range. The off-condition calculation program in this paper is also a process that needs to be continuously verified. It is necessary to combine more and more abundant numerical and experimental results to improve the calculation method and the revised parameters. The significance of this paper is to understand the performance of the compressor in the design stage and to shorten the design period in the overall design of the centrifugal compressor. Improve the efficiency of the design.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH452

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