某涡轮叶片热-机械疲劳寿命预测与试验验证

为了得到某燃气轮机涡轮叶片关键截面的真实寿命,设计并开展了涡轮叶片热-机械疲劳试验,获得了真实寿命数据,并基于试验结果提出了一种涡轮叶片低周疲劳与蠕变疲劳交互的寿命预测方法。首先,采用一维线弹性关系、修正公式以及循环应力应变关系3种名义应力应变处理模型计算获得了名义应变;然后,利用SWT寿命关系式预测模型预测了叶片的热-机械疲劳寿命;再将预测寿命与试验获得的真实寿命进行对比分析。研究表明：对于某型燃气轮机涡轮叶片,基于SWT预测模型的循环应力应变关系方法相比于一维线弹性关系和修正公式法预测精度最高,与试验寿命相比,预测误差在4倍分散带之内。     

舰用燃气涡轮叶片材料的蠕变寿命模型研究

本文在金属材料典型蠕变过程的基础上,分别研究了蠕变各个阶段的本构模型。针对金属材料在较高应力下没有蠕变稳定阶段的现象,提出了金属材料高低应力值的判定准则并根据高低应力的不同特点推导了不同的耦合损伤本构模型。通过对舰用燃气轮机涡轮叶片材料的蠕变试验结果与模型预测结果进行比较可以看出：本文提出的蠕变模型近似地模拟金属材料的蠕变全过程,准确地预测金属材料的蠕变寿命。     

涡轮叶片多轴低周疲劳／蠕变寿命研究

本文针对电厂用燃气轮机涡轮叶片工作环境,对Manson—Coffin多轴疲劳预测方程和WWT公式进行修正,同时采用尚德广多轴疲劳损伤参量,给出涡轮叶片新的疲劳寿命预测方法,以适应涡轮叶片高温变幅非比例加载下疲劳损伤情况。通过算例计算了某涡轮叶片疲劳寿命及10000工作小时的总损伤,与叶片实际疲劳破坏相吻合,验证该高温多轴疲劳损伤计算模型的准确性。     

汽轮机隔板高温蠕变寿命评估方法的研究

针对现役引进型机组高温蠕变现象难于正确评估的情况,提出了根据机组历次大修记录的变形数据和有限元计算相结合的方法得到材料蠕变参数.采用该方法对某电厂600 Mw机组T11 级隔板的高温蠕变变形问题进行了分析研究,并应用商用软件对隔板在继续运行中的变形和应力情况作出了预测和评估.结果表明:隔板最大应力产生的位置在隔板外环叶片的出汽侧,靠近中分面边缘叶根、叶片的出汽边处,其值为160 MPa,按每年连续运行8 000 h计算,隔板的使用寿命约为30年,与制造商提供的设计寿命一致,得出了机组在一个大修期内不必立即更换隔板的结论,节约了维修费用,为汽轮机或燃气轮机高温部件的蠕变寿命的评估提供了一种实用方法.     

燃气轮机透平叶片流-热-固耦合分析及蠕变寿命预测

本文采用流-热-固耦合方法,对某燃气轮机透平动叶的流场、温度场以及应力分布进行了计算分析,并据此对叶片的蠕变寿命进行了计算,得到了蠕变寿命云图,发现该叶片的寿命最短点与温度最高点、应力最大点不在同一位置。相较于传统的选取温度最高和应力最大的节点作为危险点进行寿命分析的方法,对叶片所有节点进行寿命计算,形成寿命云图的方法,能更加直观准确地找到寿命最短的位置,从而更好地评估设计方案。     

基于热力学方法的海上平台燃气轮机涡轮叶片热腐蚀影响评估研究

为了有效评估燃料气中H2S超标对燃气轮机涡轮叶片热腐蚀的影响,在腐蚀机理研究基础上结合燃机的运行参数条件,采用热力学模拟方法完成了对25 MW燃气轮机涡轮叶片热腐蚀风险评估分析。通过分析杂质含量变化及燃料类型对腐蚀产物露点曲线的影响,得出了碱金属含量是涡轮叶片热腐蚀的关键影响因子,在（Na+K）质量分数小于1×10-5%的条件下,即使当H2S体积分数达到0.01%时,涡轮叶片也不会面临热腐蚀风险。这将对海上平台用国产25 MW燃气轮机燃料中杂质含量目标控制和高温涡轮叶片防护涂层设计起到了一定的参考作用。     

基于热力学方法的海上平台燃气轮机涡轮叶片热腐蚀影响评估研究

为了有效评估燃料气中H_2S超标对燃气轮机涡轮叶片热腐蚀的影响,在腐蚀机理研究基础上结合燃机的运行参数条件,采用热力学模拟方法完成了对25 MW燃气轮机涡轮叶片热腐蚀风险评估分析。通过分析杂质含量变化及燃料类型对腐蚀产物露点曲线的影响,得出了碱金属含量是涡轮叶片热腐蚀的关键影响因子,在(Na+K)质量分数小于1×10~(-5)%的条件下,即使当H_2S体积分数达到0.01%时,涡轮叶片也不会面临热腐蚀风险。这将对海上平台用国产25 MW燃气轮机燃料中杂质含量目标控制和高温涡轮叶片防护涂层设计起到了一定的参考作用。     

涡轮机叶片磨损测量技术试验研究

1前言涡轮机叶片的磨损直接影响涡轮机的性能、可靠性和寿命。船用燃气轮机叶片涂层磨损后,叶片的基体材料在燃气轮机高温烟气产生的近1 000℃的环境中所引起的高温腐蚀和高温蠕变会严重影响机组的可靠性和寿命。船用汽轮机工作在高湿度蒸汽中的叶片,长期受水滴的高速冲蚀,极易     

整圈连接叶片高温蠕变与松弛特性分析

随着汽轮机叶片进口参数越来越高,叶片对材料的高温力学性能提出了更高的要求,在高温下材料的力学特性远低于其在常温下的所承受的范围,在高温下材料会发生蠕变和应力松驰现象,应用"characteristic strain"蠕变模型来分析高温叶片的蠕变和应力松弛行为,该蠕变模型是阿尔斯通叶片专家J.Bolton将诺顿蠕变模型优化后得到的,该蠕变模型相比于诺顿蠕变模型大大提高了计算效率。本次高温叶片有限元蠕变计算,评估了叶片在高温下的安全性及机械设计完整性,良好地指导了叶片结构设计,且得到了高效、精确的高温蠕变计算方法。     

大功率汽轮机高温叶片蠕变特性数值研究

近年来汽轮机朝着大功率、高参数方向快速发展,汽轮机进口蒸汽温度不断提高,导致叶片的工作环境进一步恶化.叶片作为汽轮机的核心部件,其安全性直接影响汽轮机机组的运行状况,因此研究高温条件下叶片的强度和蠕变特性非常重要.以某大功率汽轮机高温叶片为例,构造了叶片和叶轮三维有限元模型,采用商用有限元软件ANSYS分析了离心力和温度场共同作用下的叶片热弹性应力及变形;然后,应用诺顿模型分析了该叶片经历100 000 h蠕变历程的应力和应变.建立了完整的汽轮机叶片蠕变特性分析数值模型,研究工作为汽轮机叶片的静强度和蠕变特性研究提供了具体的方法,所得结论对于高温叶片设计具有指导意义.     

Maisotsenko循环在燃气轮机进气冷却中的应用研究

采用基于Maisotsenko循环的露点间接蒸发式冷却作为进气冷却的手段,研究了不同环境条件下其对燃气轮机性能的提升效果。建立了针对某9E级燃气轮机的热力循环过程的计算模型,并利用该热力模型分析了进气温度变化对燃机出力的影响。基于Maisotsenko循环的原理,以温降为指标对露点间接蒸发冷却器的性能进行了分析。以功率和效率作为指标,对燃气轮机性能随环境条件的变化情况做了数值模拟,对露点蒸发式冷却与无进气冷却、直接喷雾式冷却对燃机性能的影响进行了计算分析。结果表明,在高温低湿度的条件下,露点间接蒸发式冷却能有效提升燃机性能。     

汽轮机叶片表面状况对疲劳寿命的影响

汽轮机叶片的疲劳操作和疲劳寿命除与交变应力、平均应力、材料的强度和循环性能、运行条件等有关外,在相当大程度上与叶片表面状况（应力集中、加工状况、强化、腐蚀介质、微动磨损等）有关。本文深入研究了叶片表面状况对疲劳寿命的影响,采用改进的局部应力应变法对实际叶片进行的相应计算、对比和分析表明,叶片的疲劳寿命对表面状况很敏感。研究工作对叶片状况、制造、运行及故障分析有着现实的理论和工程应用价值。     

双层壁叶片的模型化方法与冷却设计流程研究

提出了一种适用于双层壁叶片的冷却设计流程。沿叶片的叶高和流向抽象提取出简单冷却单元,对其建立一维管网模型并进行多次管网计算,得出各个单元最优的冷却结构方案。将设计好的冷却单元映射回实际叶片中,并对叶片建立一维管网模型,经过多次冷却结构调整与计算迭代,得到叶片初步的冷却结构。对该叶片进行三维气热耦合计算,只需要局部冷却结构微调和少量的CFD计算,就可以得出最终的冷却设计方案。最终设计的叶片CFD计算得到的平均温度为1 049 K,总冷气量为0.288 kg/s,与管网计算结果1 059 K和0.337 kg/s相近。该设计流程方法简便,准确性高,人工工作量和仿真计算量小,优于传统的涡轮冷却设计流程。     

Aeroelastic multidisciplinary design optimization of a swept wind turbine blade

Mitigating loads on a wind turbine rotor can reduce the cost of energy. Sweeping blades produces a structural coupling between flapwise bending and torsion, which can be used for load alleviation purposes. A multidisciplinary design optimization (MDO) problem is formulated including the blade sweep as a design variable. A multifidelity approach is used to confront the crucial effects of structural coupling on the estimation of the loads. During the MDO, ultimate and damage equivalent loads are estimated using steady‐state and frequency‐domain–based models, respectively. The final designs are verified against time‐domain full design load basis aeroelastic simulations to ensure that they comply with the constraints. A 10‐MW wind turbine blade is optimized by minimizing a cost function that includes mass and blade root flapwise fatigue loading. The design space is subjected to constraints that represent all the necessary requirements for standard design of wind turbines. Simultaneous aerodynamic and structural optimization is performed with and without sweep as a design variable. When sweep is included in the MDO process, further minimization of the cost function can be obtained. To show this achievement, a set of optimized straight blade designs is compared to a set of optimized swept blade designs. Relative to the respective optimized straight designs, the blade mass of the swept blades is reduced of an extra 2% to 3% and the blade root flapwise fatigue damage equivalent load by a further 8%.     

限功率控制下风电机组叶片疲劳损伤研究

基于叶素-动量理论计算风电机组叶片气动载荷,建立其疲劳载荷模型;将叶片简化为悬臂梁,采用雨流计数法、Goodman经验公式和Miner线性累计损伤理论计算风力机叶片疲劳损伤和等效疲劳载荷;根据2种限功率控制策略计算不同限功率水平和湍流强度下风力机叶片单位时间的疲劳损伤量,分析限功率运行工况对叶片疲劳损伤的影响。结果表明,新型限功率控制策略可减少变桨系统的动作频率和动作幅度,但其稳定运行状态对叶片的疲劳损伤量大于传统限功率控制策略。最后通过三维函数拟合得到疲劳损伤函数,可应用于限功率条件下风电场优化调度。     

An experimental investigation of the heat transfer in a ribbed triangular cooling channel

One of the most challenging aspects of gas turbine cooling is the cooling of the first stages of turbine blades. Here the highest external heat load is seen at the leading edge of the blade. The present study investigates the internal cooling in a triangular channel with a rounded edge as a model of a leading edge cooling channel for a gas turbine blade. A transient liquid crystal method is used to measure the heat transfer. Experimental results are reported for a number of new 3D rib configurations for Reynolds numbers between 50 000 and 200 000. From the experimental results it has been found that 60 deg. ribs provide in general higher heat transfer enhancements than 45 deg. ribs. However, this results in extremely high friction factors for the 60 deg. ribs. Taking the local and mean distributions of the heat transfer coefficients (as well as the increase in friction factors) into consideration, it was found that the most promising rib arrangement for leading edge cooling is a 3D rib with 45 deg. angle and double-sided fully overlapped ribs in the arc area. These ribs provide uniform heat transfer in the arc area as well as a high level of the heat transfer coefficients in the channel. The resulting friction factors are in an acceptable range for these ribs.     

Structural investigation of composite wind turbine blade considering various load cases and fatigue life

This study proposes a structural design for developing a medium scale composite wind turbine blade made of E-glass/epoxy for a 750 kW class horizontal axis wind turbine system. The design loads were determined from various load cases specified at the IEC61400-1 international specification and GL regulations for the wind energy conversion system. A specific composite structure configuration, which can effectively endure various loads such as aerodynamic loads and loads due to accumulation of ice, hygro-thermal and mechanical loads, was proposed. To evaluate the proposed composite wind turbine blade, structural analysis was performed by using the finite element method. Parametric studies were carried out to determine an acceptable blade structural design, and the most dominant design parameters were confirmed. In this study, the proposed blade structure was confirmed to be safe and stable under various load conditions, including the extreme load conditions. Moreover, the blade adapted a new blade root joint with insert bolts, and its safety was verified at design loads including fatigue loads. The fatigue life of a blade that has to endure for more than 20 years was estimated by using the well-known S–N linear damage theory, the service load spectrum, and the Spera's empirical equations. With the results obtained from all the structural design and analysis, prototype composite blades were manufactured. A specific construction process including the lay-up molding method was applied to manufacturing blades. Full-scale static structural test was performed with the simulated aerodynamic loads. From the experimental results, it was found that the designed blade had structural integrity. In addition, the measured results of deflections, strains, mass, and radial center of gravity agreed well with the analytical results. The prototype blade was successfully certified by an international certification institute, GL (Germanisher Lloyd) in Germany.