共查询到19条相似文献,搜索用时 156 毫秒
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提高军用燃气涡轮发动机的性能的关键是提高涡轮前燃气温度,涡轮前燃气温度受到材料和冷却技术的制约。探索新的高效冷却方法对于提高涡轮前燃气温度有重要的作用。本文分别采用圆环和球壳模型,对具有重要应用前景的涡轮叶片新型冷却方法的泡沫多孔结构及细微冷却通道周边区域的应力进行具体的分析,对该结构的强度可行性进行了初步的论证,为这一新型冷却方法的进一步研究奠立结构强度分析的基础。 相似文献
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针对燃气轮机中涡轮的设计,介绍了杭汽燃气涡轮气动设计体系,并阐述了冷却涡轮掺混损失计算方法和几种效率定义方法。通过一维热力设计和S2流面完全径向平衡方程设计,设计出了三级燃气涡轮。应用计算流体力学软件CFX对所设计的涡轮进行了不带冷气的性能分析,应用源项法对带冷气的涡轮进行了性能分析。通过三维计算,得到了新设计的三级涡轮的折合流量、折合转速、效率的特性曲线;并为涡轮的进一步气动优化设计和强度振动校核打下了基础。计算结果显示:设计的涡轮气动性能良好,变工况性能宽,基本达到了设计要求;不带冷却涡轮效率91%,带冷却的涡轮效率89.7%。 相似文献
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在我国制造业的进一步发展之下,对于整机发电效率的要求也越来越高,因此,人们开始尝试通过提升燃气轮机涡轮中燃气的进口温度,以有效实现燃气轮机的性能优化。而在此过程中,燃气涡轮导叶冷却结构则直接影响着燃气轮机的实际运行,基于此,本文尝试对燃气涡轮导叶冷却结构设计及数值模拟进行简要分析研究。 相似文献
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综述了近年来重型燃机透平冷却结构、冷却剂、涂层和材料、新技术等在冷却技术中的发展,分析发现通过改进这些因素能逐步满足日益增长的透平进口温度要求,同时阐述了目前透平冷却技术中各种方法对流动和换热的影响,各种因素综合考虑将是今后工作的重点。 相似文献
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针对镍基高温合金切削过程中存在的过热烧伤问题,提出采用定向内冷切削方法提高冷却液在切削区的换热效率。采用FLUENT软件建立定向内冷车刀的流场与温度场模型,分析微流道结构对刀具换热性能的影响,对刀具微流道结构进行设计,研制了定向内冷式切削系统。采用相同的切削加工参数,在干切削、外部浇注切削和定向内冷切削三种冷却环境下进行镍基高温合金切削对比试验,分析了冷却方式对切削力、切削温度、加工表面粗糙度和表面微观形貌的影响规律,结果表明:定向内冷方法可有效减小切削力并降低切削温度,获得表面粗糙度更小、纹理更为规整的加工表面。 相似文献
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Rapid casting of turbine blades with abnormal film cooling holes using integral ceramic casting molds 总被引:2,自引:2,他引:0
Haihua Wu Dichen Li Xiaojie Chen Bo Sun Dongyang Xu 《The International Journal of Advanced Manufacturing Technology》2010,50(1-4):13-19
Film cooling is an important cooling method to decrease the turbine blade surface temperature, and its average cooling efficiency is mainly dependent on the cooling structures of internal passageways and the shapes of film cooling holes. Compared with standard cylindrical film cooling holes, abnormal film cooling holes have higher average cooling efficiency. But it is difficult to manufacture these holes using traditional machining methods. In this paper, a novel process was developed to fabricate turbine blades with abnormal film cooling holes by combining stereolithography (SL) technology with gelcasting technology. To decrease the drying shrinkage, the freeze-drying technique was applied to treat the wet ceramic casting mold green body surrounded by the SL mold, and the proper sintering process parameters were determined for lowering the sintered shrinkage. Finally, the integral ceramic casting mold was obtained, and a turbine blade with converging–diverging film cooling holes was rapidly cast to verify the feasibility of the proposed process. 相似文献
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介绍了M701F燃机透平冷却系统技术要求,总结了冷却系统典型故障对机组运行的影响并提出了相应的对策措施。同时,研究了透平冷却空气对燃气轮机的影响机理,对机组的安全运行及维护具有重要借鉴意义。 相似文献
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Junsik Lee Jin Sub Kim Hyungsoo Lim Je Sung Bang JeongMin Seo Jeong Lak Sohn Jungho Lee 《Journal of Mechanical Science and Technology》2017,31(11):5113-5121
Effusion cooling can be one of the attractive methods of cooling in a current high-efficiency gas turbine which has a very hot gas temperature above 1600 °C. For higher effectiveness of the air cooling for a gas turbine vane and blade, the air-cooled flow through effusionholes should not overshoot into the mainstream flow but still remain within the mainstream boundary layer. The present study is intended to examine flow structure of a microscale effusion cooling for gas turbine applications through flow visualization which is highly effective to obtain better understanding of the flow physics. The air flow through effusion-holes can be visualized with an oil atomized droplets, a laser-sheet and a high-speed CCD imaging system. The qualitatively visualized results show their flow patterns and characteristics with different effusion hole size and blowing ratio for effusion cooling. A series of vortical structure can be observed within the boundary layer along the microscale effusion flat plate which provided that the effusion cooling can be a plausible candidate up to the effusion-hole size of 0.7 mm. 相似文献
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Gas/steam combined cycle is synergetic combination of Brayton cycle based topping cycle and Rankine cycle based bottoming cycle, which have capability of operating independently too. Combined cycle performance depends on the constituent cycles and it can be reasonably improved by enhancing gas cycle performance using gas turbine blade cooling. Amongst different cooling techniques the transpiration cooling offers effective utilization of coolant as compared to film cooling because of better shrouding of blade surface as the coolant is discharged from entire blade surface. The present work deals with evaluation of performance enhancement of combined cycle by using steam transpiration cooling of gas turbine blades. The combined cycle performance parameters e.g. overall efficiency and specific power output etc. have been compared for air transpiration cooling and steam transpiration cooling. The results revealed that for the specified conditions the steam is superior coolant in comparison to air and the combined cycle performance can be enhanced by applying transpiration cooling in gas turbine blades with steam as coolant. With a turbine inlet temperature of 1800 K and compressor pressure ratio of 23, the combined cycle efficiency with steam transpiration cooling of gas turbine blades is higher by 1.94 percent approximately as compared to the efficiency of combined cycle with air transpiration cooling of gas turbine blades. 相似文献
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在概述了金属切削液及其发展的基础上,指出了目前冷却方法即使用切削液过程中存在的主要问题;列举了当前国内外在探索新的冷却方法方面的进展,提出在世界性环境意识提高的大背景下,少、无切削液加工技术将是制造业未来发展的一个重要趋势。 相似文献
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切削加工冷却方法的现状与发展 总被引:4,自引:0,他引:4
在概述了金属切削液及其发展的基础上,指出了目前冷却方法即使用切削液过程中存在的主要问题;列举了当前车内外在探索新的冷却方法方面的进展,提出在世界性环境意识提高的大背景下,少、无切削液加工技术将是制造业未来发展的一个重要趋势。 相似文献