【作者】 海洋；

【导师】 谢蓉；

【作者基本信息】 大连理工大学 ， 动力机械及工程， 2009， 硕士

【摘要】 微型燃气轮机作为广泛用于小型分布式发电的动力装置,具有较为灵活、安全、洁净的优点,是一种廉价的发电和热电联供方式,符合国家对能源供给多样化的发展要求;而且微型燃气轮机可以用于我国缺水地区,这符合我国21世纪可持续发展的战略思想。但是由于微型燃机体积小、通流结构尺寸相对窄小,造成燃机元件的效率不高。针对这一现象,本文对某公司WD095型微型燃机的主要组成元件——离心压气机的通流结构和设计工况下的性能进行研究,以减少损失、进一步提高其效率。本文围绕离心压气机两大核心部件叶轮和扩压器开展了一系列研究。叶轮方面,主要完成了“半开式离心叶轮的叶顶间隙研究”和“离心叶轮分流叶片的偏置设计研究”。利用流场模拟计算软件NUMECA和有限元分析软件ANSYS,结合气动理论和结构分析理论,对离心叶轮通流结构展开详细研究。针对本文所研究的半开式离心叶轮,推荐了较为合适的叶顶间隙值为0.2mm。研究发现:合理地周向偏置分流叶片可以有效抑制流道横截面内的二次流动,明显改善叶轮流道内的流动状况;当分流叶片进口居中,而其出口与长叶片压力面之间的周向距离是两相邻长叶片之间的周向距离的44.4%时,叶轮性能最好。扩压器方面,从附面层控制技术出发,完成了两种叶型的错排叶栅扩压器的设计及性能初探。在一维热力设计的基础上,利用NUMECA分别计算分析了原设计叶型相似缩小和NACA-65叶型两种错排设计扩压器内的流动情况,得出:错排叶栅扩压器可以有效抑制扩压器内气流分离,减少损失,提高效率。目前,本文所研究的压气机叶轮和扩压器连算结构的效率较原设计结构可以提高2个多百分点,这说明错排叶栅扩压器具有较大的研究价值,有必要进行更为深入的研究。更多还原

【Abstract】 The micro gas turbine（MGT） is a type of low-cost and combined heat and power generation,widely used in minitype distributed power generation,for its advantages of more agility,safety and low emission.It meets the great diversified demand of the development of our country’s energy supply.Moreover,the MGT can be used in the water-scarce area,which accords with the strategy of 21^st sustainable development.But owing to its compactness and relatively small size of the through-flow structure,the efficiency of the components of MGT is relatively low.Thus,this paper is mainly focused on the research and the performance under designed conditions of a centrifugal compressor of high pressure ratio and high rotating speed,a pivotal component of WD095 micro gas turbine,with the purpose of reducing flow loss and further advancing efficiency.In this paper,a series of investigations were carried out with regard to the impeller and the diffuser,two core parts of the centrifugal compressor.For the unshrouded impeller,the size of blade tip clearance and the circumferential position of splitter blades were studied and analyzed.Based on the aerodynamics and the structure analysis theory,the through-flow structure was investigated numerically in detail,by using the CFD software-NUMECA and the finite-element analysis software-ANSYS.According to the numerical results,0.2mm tip clearance was recommended for this impeller.The investigation also shows that:reasonable circumferential position of splitter blades can availably restrain the secondary flow in the through flow cross section,and apparently improve the internal flow condition in the impeller. The performance of the impeller is the best in all design projects,while the circumferential distance of the splitter blade trailing edge between splitter blade and the pressure side of main blade is 44.4%of the distance between two main blades,and its leading edge is located in the middle of two main blades.Then two types of staggered arrangement cascade diffusers were designed respectively with the similarly reduced blade profile of the initial design and NACA-65.The internal flow condition was numerically simulated and analyzed for the two types of diffusers respectively with the similarly reduced blade profile of the initial design and NACA-65.The simulation results indicate that the staggered arrangement cascade diffusers can restrain the flow separation effectively,decrease flow loss and increase efficiency.And the efficiency of the combining structure of the impeller and the staggered arrangement cascade diffuser is increased by more than 2 percentage points compared with the initial design.It is shown the staggered arrangement cascade diffuser is worth to further study.更多还原