【作者】 孙琦；

【导师】 冀春俊；

【作者基本信息】 大连理工大学 ， 流体机械及工程， 2018， 博士

【摘要】 压缩机在运行过程中受气候影响及客户需求需要经常调节气体的流量,很多情况下通过在进口加装进口导向叶片的方法来控制流量,但目前由于进口导向叶片调节流量的能力普遍不足,导致在冬季由于气量过剩而排空浪费掉,最多的时候要浪费高达30%的气量,造成能源的浪费,目前国际先进水平最多仅需排空15%的气量,因此改进进口导叶的设计,开发出高效流量调节装置是我国目前压缩机行业急需解决的关键技术之一,对于提高我国压缩机设计技术,提升企业竞争力具有重要的意义,同时对于节能减排具有重大的现实意义。本文从进口导叶调节装置的结构、调节机理和对叶轮压缩功的影响等方面对导叶调节的基本理论做了详细论述,并以导叶自身的调节能力和对压缩机性能的影响两方面阐明了进口导叶调节装置的评价体系。介绍了应用于叶轮机械数值模拟技术的相关理论知识,建立了带进口导叶的压缩机实体模型,利用计算流体力学的方法对导叶不同开度下的流场分布规律做全面的研究与分析,揭示了导叶调节时的一些重要流动现象。导叶在绕其自身转轴旋转时为了避免与机匣端壁发生碰撞,会在导叶顶部留有圆弧状的间隙,部分气流从间隙处流过而得不到有效调节,并形成叶顶间隙泄漏涡,对主流造成影响,使压缩机性能下降。针对这一问题,本文提出了三种导叶通道结构形式的改进方案,有效地提高了导叶的调节能力,扩大了压缩机的稳定工况范围,减少了压缩机的功耗,提高了压缩机的效率。为了探究导叶叶片形状对导叶调节能力和压缩机性能的影响,本文分别对导叶叶片型面的厚度、弯曲度和最大挠度位置做系统的研究和分析,总结出这几项参数的变化对导叶调节性能影响的规律。为了找出调节性能最好的进口导叶叶片形状,本文采用现代优化方法对进口导叶的叶片型面进行三维的优化设计,主要的方法学思想是以人工神经网络对连续设计进行适应度评价,并用遗传算法进行全局寻优。经过优化后,导叶的调节性能有了显著的提高,大大增强了导叶的预旋能力,并减少了压力损失,使压缩机的流量和功率在导叶安装角较大时大幅减少,效率显著提高,同时使导叶通道内的流场有了明显改善,使原来的流场分布不均匀和流动分离等现象大幅减弱,甚至完全消失。最后,对本文所提出的三种改进后的叶顶通道结构形式和优化叶型的进口导叶装置进行试验测试,并与原始形式进行对比,结果证明了本文研究成果的可靠性。最终,应用改进优化后的进口导叶调节装置可使压缩机在冬季运行时减少20%左右的压缩气体排空浪费量,同时降低压缩机20%左右的功耗,并提高了压缩机的效率和稳定工况范围。此项课题的研究成果可应用到工业生产各个领域中的离心压缩机中,在压缩机进口处加装这种高效的流量调节装置可以使其在冬季运行时大幅减少压缩气体的排空浪费量及功耗,并提高压缩机的效率,提升能源的利用率,避免能源的浪费,因此具有很广阔的应用前景。更多还原

【Abstract】 In the process of operation,the mass flow of compressor should be always regulated according to climate change and customer needs.In many cases,the flow rate is controlled by VIGV(Variable Inlet Guide Vane).Currently,the inlet guide vane’s regulating capacity is not enough,resulting in excessive compressed gas would be exhausted in winter.Sometimes,the waste of compressed gas is up to 30%,causing a waste of energy,while the current international advanced technology can only waste 15%of that.Thus,the improvement of inlet guide vane and the development of high efficiency flow regulation device are the key technology in the compressor area in China.It is of great significance to enhance the competitiveness of enterprises,and has important practical significance for energy conservation and emission reduction.This paper discusses the basic theory of inlet guide vane regulation in detail,including the structure of inlet guide vane,regulation mechanism and the effect of impeller compression work,etc.The evaluation system of inlet guide vane regulation is expounded intwo aspects:the regulation ability of guide vane and the influence on compressor performance.Introduce the theory knowledge of the numerical simulation technology of turbomachinery.The solid model is established,using the CFD theory to study and analyze the flow field distribution under different guide vane setting angles.Some important flow phenomena of guide vane regulation are revealed.In order to avoid the collision between the guide vane and the end wall of the casing,a circular arc gap is arranged at the top of the guide vane,some of gas flows through the gap and cannot be effectively regulated,and the leakage vortex of the tip clearance is formed,which can affect the mainstream and decrease the performance of the compressor.To solve this problem,this paper proposes three improved schemes of inlet guide vane passage,they effectively improve the regulating ability of guide vane,and expand the stable operating range,reduce the power consumption,improve the efficiency of the compressor.In order to investigate the influence of guide vane shape on its regulating ability and compressor performance,the thickness,the curvature and the maximum deflection position of the vane cross sections are studied systematically.The influence of these parameters on the regulation performance of guide vane is summarized.In order to find the suitable shape of inlet guide vane with the best regulation performance,this paper adopts the modern optimization method to optimize the blade profile of the inlet guide vane.The main idea of the method is to use artificial neural network to evaluate the fitness of continuous design,and use genetic algorithm for global optimization.After optimization,the regulating performance of guide vane is improved significantly.It greatly improves the pre-rotation ability of the guide vane and reduces the pressure loss.The flow rate and the power of the compressor are greatly reduced when the installation angle of the guide vane is large,and the efficiency is improved obviously.At the same time,the flow field distribution in the guide vane channel is improved obviously.The original uneven flow field distribution and flow separation phenomenon is weakened,or even completely disappeared.At last,the three improved inlet guide vane channel structures and the inlet guide vane devices with optimized blade profile are tested and compared with the original ones.The results show the reliability of the research results in this paper.Finally,the application of the improved and optimized inlet guide vane regulation device can reduce about 20%of the compressed gas exhaustion when the compressor is running in winter,and reduce the power consumption of the compressor by 20%or so,and the efficiency and the range of stable working condition are increased.The research results can be applied to centrifugal compressors in various fields of industrial production.The high efficiency flow regulating device is installed at the inlet of compressor,which can greatly reduce the wastage of compressed gas and the power consumption of compressor in winter,and improve the efficiency of the compressor,enhance the utilization of energy,avoid the waste of energy,so it has broad application prospects.更多还原