【作者】 高怡秋；

【导师】 刘学义；

【作者基本信息】 哈尔滨工程大学 ， 轮机工程， 2008， 硕士

【摘要】 涡轮是燃气轮机的主要部件,其功用是将来自燃烧室的高温、高压燃气中的部分热能和压力能转换成机械功。船舶燃气轮机的特点为功率大、燃气温度高、转速高、效率高,同时对尺寸、重量有严格的要求。而对涡轮气动设计理论与设计方法的研究,以及对涡轮的数值模拟和性能优化一直是国内外叶轮机械气动热力学领域关注的重点。本文以给定涡轮设计要求为依据,对某型船舶燃气轮机动力涡轮第一级进行叶型设计,分别采用等环量以及等α₁扭曲规律对涡轮进行了三维气动设计,根据所得参数,运用参数化法生成叶型。应用商业软件NUMECA,对所生成的叶型进行了数值模拟,比较了两种扭曲规律的不同以及优劣,并将数值模拟结果与设计值进行对比,以验证数值模拟的正确性。着重对等环量叶片进行了分析,包括S₁、S₂流面分析、叶栅通道中涡系的研究、二维非定常流场特性的分析。分析了设计叶型的不足以及叶片载荷分布对气动性能的影响,通过对比压力分布,及其对总压损失系数、绝热效率的影响,确定改进方案;根据二次流损失机理,尝试对静叶、动叶采用不同弯角的弯叶片,通过数值模拟得出结论:叶片的弯曲可以控制径向压力梯度,并能够改变级的反动度沿叶片高度的分布,有效改善叶栅流场;并对静叶、动叶分别采用不同弯曲角度的多种组合模型方案进行数值模拟,提出静叶、动叶在采用弯曲叶片后由于气流角、马赫数等参数变化而引起的匹配问题,得出在采用匹配合理的静叶、动叶后,可有效提高效率;最后,对涡轮叶片采用了不同的轴向间距,并分析其对气动性能的影响。经过对叶片载荷分布、叶片弯曲、轴向间距三个方面的分析以及改进,涡轮绝热效率提高了1.84%,表明本文对涡轮的性能优化以及改进方案是降低损失、提高效率的有效手段。更多还原

【Abstract】 Turbine is a main component of a gas turbine engine, by which part of the thermal energy in the high-temperature and high-pressure gas from the combustion chamber, can be converted to the mechanical kinetic energy. A marine gas turbine is characterized with high power, high temperature, high rotating speed and high efficiency ,as well as size and weight restricted by strict rules. For these years, scholars in aerodynamics field have attached great importance on the theories and methodologies of turbine design as well as numerical simulation and performance optimization.Following the prescribed instruction of a turbine design, in this thesis, a blade shape is created for the first stair of the certain marine gas turbine. On the basis of constant circulation and iso-α₁ twisted laws, the blade shape is made by a three-dimensional aerodynamic design, and produced by parameterization. Applying NUMECA, a commercial software, the produced blade shape is simulated, the differences of two twist laws are explored, and the validity is testified by making a comparison between the outcome and the theoretical value. Then a series of analyses on constant circulated blade are conducted, which include analyses of the S₁ stream surface and the S₂ stream surface, discussions of the vortices in the cascades, analyses of the features in two-dimensional unsteady flow field, etc.After that, it is found that the defects of the designed blade shape exist, and the influences of load distribution on the aerodynamic performance. Then some improvements can be managed after considering the profile pressure distribution, as well as the total pressure loss coefficient and adiabatic efficiency which is influenced by the profile pressure distribution. According to the secondary flows loss theory, several trials are conducted on stator blade and rotor blade by different curve angles, and the conclusion can be draw after numerical simulation: the curved blade can control the radial pressure gradient, change the distribution of the reactionary degrees over the blade height and promote the flow field in cascade. This is followed by various compound models with different curve angles on stator blade and rotor blade, and consequently a matching question about caused by several parameters such as flow angle, Mach number is discussed, which can be solved by deploying proper ones. Finally, different blade axial intervals between the stator and the rotor are tried to observe the influences on aerodynamic performance.After the speculation and promotion, turbine’s adiabatic efficiency is raised by 1.84%, which proves the effectiveness of the optimizing and improving approaches of this project in decreasing loss and lifting efficiency.更多还原