涡轮叶片尾缘扰流柱通道流动换热计算

为了深入研究涡轮叶片尾缘扰流柱区域流动的工程计算方法,用开发的基于流体网络计算的一维工程算法,对工作叶片尾缘扰流柱通道进行了计算,并与实验结果进行了对比。计算结果表明:工程计算得出的弦向出流量分布、压力分布从规律和数值上与实验结果都吻合较好,工程算法能够比较准确地计算出扰流柱通道的流动;扰流柱区的气体流动方向基本为弦向,但也存在着一定的径向流动,所以有必要在流体网络计算中设置表示径向流动的流路。     

进口气流角对三维振荡涡轮叶片非定常流动影响的数值模拟研究

进一步发展了非定常雷诺平均N—S方程求解程序,并基于影响系数法,在三种不同振型下就进口气流角对三维涡轮振荡叶片绕流的影响进行了数值模拟研究。数值模拟结果表明,所发展的程序对振荡叶栅流动模拟具有较好的精度;进口气流角对振荡叶栅内部非定常流动以及叶片表面的非定常气动力有着较为重要的影响,且在不同模态下,进口气流角对振荡叶片非定常流动的影响规律表现不同。     

稠度和压比对叶栅反推器叶片反推性能的影响

建立了外涵叶栅反推器的轴对称计算模型;给出了内涵计算域的有效处理方法;利用数值模拟手段,研究了叶片稠度、外涵入口压比的变化对反推效率、流量系数等的影响规律;将计算结果与可能得到的试验结果的数据点进行了比较,结果表明计算结果与试验结果吻合,当叶片稠度小于1.59时,增大叶栅稠度可使流量系数和反推效率同时增大,但继续增大稠度,虽可使流量系数略有增大,但由于气流出口转向受到的影响不大,反推效率波动范围不大。     

Application of shear-sensitive liquid crystal coating to visualization of transition and reattachment in compressor cascade

The present paper aims at introducing Shear-Sensitive Liquid Crystal Coating (SSLCC) technology into compressor cascade measurement for the first time and serves as a basis for better understanding of the influence from the boundary layers. Optical path layout, which is the most significant difficulty in internal flow field measurement, will be solved in this paper by self-designed image acquisition device. Massive experiments with different Mach number and incidence are conducted at a continuous subsonic cascade wind tunnel to capture the boundary layer phenomenon. Image processing methods, such as Three-Dimensional (3-D) reconstruction and Hue conversion, are used to improve the accuracy for transition position detection. The analysis of the color-images indicates that complex flow phenomena including transition, flow separation, and reattachment are captured successfully, and the effect of Mach number and incidence on the boundary layer flow is also discussed. The results show that: the Mach number has a significant effect on transition position; the incidence has little effect on transition position, but it has a great impact on the transition distance and leading-edge separation; influenced by the end-walls, the reattachment occurs in advance under positive angle of attack conditions.     

Identification of crystal orientation for turbine blades with anisotropy materials

A novel approach to identify the crystal orientation of turbine blades with anisotropy materials is proposed. Based on enhanced mode basis, with the main advantages of its efficiency, accuracy and general applicability, the blade vibration mode of each order is linearly constructed by several specified mode shapes, which are obtained from the considered turbine blade with specified crystal orientations correspondingly. Then, a surrogate model based on Kriging method is introduced for constructing the condensed perturbed matrix of stiffness in order to improve the efficiency even further. The constructed surrogate model allows to perform the modal analysis of turbine blades with arbitrary crystal orientations in higher efficiency, due to the fact that the elements of condensed perturbed matrix of stiffness are considered in construction of the surrogate model rather than concerning the perturbation of all the elements of the initial stiffness matrix for the blade. Genetic algorithm is finally employed to optimize the defined fitness functions in order to identify the crystal orientation angles of turbine blades. Several corresponding examples demonstrated the accuracy, efficiency and general applicability of the proposed method.     

近零冲角下大折转角正弯叶栅壁面静压的实验研究

实验研究了近零冲角条件下叶片正弯曲对某大折转角扇形扩压叶栅壁面静压的影响。结果表明:直叶片吸力面静压系数等值线呈现明显的反"C"型分布,采用正弯叶片后反“C”型压力分布的强度逐渐增大;流道内静压被重新分布,其中流道内径向压力梯度的改变对附面层和损失发展影响最大;正弯叶片引起的叶展中部损失的激增是导致总损失增大的主要因素,其中15°正弯叶栅改善流动、减小损失的效果最好。     

基于扇形叶栅的畸变流场对压气机静叶气动性能影响研究

随着飞机适航要求的提高，进口畸变对燃气轮机的影响也逐渐被重视起来。而飞行过程中燃气轮机所遇到的进口畸变经过动叶的传递后，往往会严重影响静叶进口气流角分布的均匀性，并恶化静叶的通流能力。为研究气流角畸变对静叶流场的影响，针对带有可调导叶的扇形叶栅，通过单独调整一片导叶角度而其它导叶角度不变的方式制造静叶进口畸变流场，并开展实验与仿真研究，分析该方法制造的畸变流场结构及其对静叶气动特性的影响。研究表明，采用的8号导叶旋转6°而其它导叶角度不变的方法可以改变静叶进口气流角、轴向速度、静压等参数的周向均匀度，实现静叶进口畸变流场。与均匀进口相比，气流角畸变度为3.22，气流角畸变度增加了1.14，并增加了静叶S8吸力面根部下通道涡的损失与影响范围，而对叶顶与中径处的影响相对较小。此外，受畸变流场影响的静叶流道总压恢复系数较均匀条件下略有下降。     

高压涡轮工作叶片内部流场特性试验研究

为研究变工况特性下涡轮叶片内部通道流场特性，选取高压涡轮二级工作叶片内部通道作为研究对象，在5种不同的进口雷诺数（Re）工况下，利用TRPIV（时序PIV）技术对通道内的流场特性进行了试验研究。Re变化为32426～64700，模拟了飞行循环过程中的若干典型工况。在先进加工技术的辅助下，保留了真实叶型约束下的完整内冷三通道带肋结构，捕捉到一些不同于常规截面两通道模型等简化模型中的流动现象，包括：弯头区域不对称主流分离结构和非对称二次涡系。通过数据分析，明确了高、低雷诺数下流动特性的差异。在高Re工况条件下，弯头出口附近的冲击区域增大；对于第一通道内的二次流，在接近弯头位置处，横向速度分量会导致纵向涡对的强度被削弱，高Re工况下拥有更加剧烈的影响，极有可能削弱吸力面的换热强度。     

Optimization of cooling structures in gas turbines:A review

Attempts for higher output power and thermal efficiency of gas turbines make the inlet temperature of turbine to be far beyond the material melting temperature. Therefore, to protect the airfoil in gas turbine from hot gas and eventually prolong the lifetime of the blade, internal and film cooling structures with better thermal performance and cooling effectiveness are urgently needed.However, the traditional way of proceeding involves numerous simulations, additional experiments,and separate tr...     

Heat transfer characteristics in a narrow confined channel with discrete impingement cooling

Heat transfer characteristics in a narrow confined channel with discrete impingement cooling were investigated using thermal infrared camera. Detailed heat transfer distributions and comparisons on three surfaces with three impact diameters were experimentally studied in the range of Reynolds number of 3000 to 30000. The experimental results indicated that the strong impingement jet leaded to a high strength heat transfer zone in the ΔX=±2.5D_j range of the impact center,which was 1.3–...