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Data mining optimization of laidback fan-shaped hole to improve film cooling performance

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Journal of Central South University 2017年第5期24卷 1183-1189页

作者： WANG Chun-hua zhang jing-zhou zhou Jun-hui College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Collaborative Innovation Center of Advanced Aero-Engine Beijing 100191China

To improve the cooling performance, shape optimization of a laidback fan-shaped film cooling hole was performed. Three geometric parameters, including hole length, lateral expansion angle and forward expansion angle, were selected as the design parameters. Numerical model of the film cooling system was established, validated, and used to generate 32 groups of training samples. Least square support vector machine(LS-SVM) was applied for surrogate model, and the optimal design parameters were determined by a kind of chaotic optimization algorithm. As hole length, lateral expansion angle and forward expansion angle are 90 mm, 20° and 5°, the area-averaged film cooling effectiveness can reach its maximum value in the design space. LS-SVM coupled with chaotic optimization algorithm is a promising scheme for the optimization of shaped film cooling holes.

关键词： gas turbine laidback fan-shaped film cooling holes optimization support vector machine (SVM) chaotic optimization algorithm

Application of Grey Situation Decision-Making Theory in Site Selection of a Waste Sanitary Landfill

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Journal of China University of Mining and Technology 2006年第4期16卷 393-398页

作者： CAO Li-wen CHENG Yun-huan zhang jing zhou Xiao-zhi LIAN Cui-xia College of Mineral Resource and Earth Science China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

An application of an unequal-weighted multi-objective decision making method in site selection of a waste sanitary landfill is discussed. The eight factors, which affected possible options, were: size and capacity of the landfill, permeability of the stratum, the average difference in elevation between the groundwater level and the bottom of the landfill pit, quality and source of clay, the quality grade of the landfill site, the effect of landfill engineering on nearby residents, distance to the water supply and the water source as well as the cost of construction and waste transport. These are determined, given the conditions of the geological environment, the need for environmental protection and landfill site construction and transportation related to the design and operation of a sanitary landfill. The weights of the eight factors were further investigated based on the difference in their relevance. Combined with practical experience from Xuzhou city (Jiangsu province, China), the objectives, effects and weights of grey decision-making were deter- mined and the process and outcome of the landfill site selection are stated in detail. The decision-making results have been proven to be acceptable and correct. As we show, unequal-weighted multi-objective grey situation decision-mak- ing is characterized by easy calculations and good maneuverability when used in landfill site selection. The number of factors (objectives) affecting the outcome and the quantitative method of qualitative indices can be adjusted on the basis of concrete conditions in landfill site selection. Therefore, unequal-weighted multi-objective grey situation decision making is a feasible method in selecting landfill sites which offers a reference method for landfill site selection else- where. It is a useful, rational and scientific exploration in the choice of`a landfill site.

关键词： solid waste sanitary landfill site selection grey decision-making unequal-weighted multi-objective

Conflict Resolution Based on Collaborative Design of Grid Services

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Wuhan University Journal of Natural Sciences 2008年第4期13卷 490-494页

作者： LUO Zuomin zhang jing zhou Hongfang CHEN Xinhua School of Computer Science and Engineering Xi＇an University of Technology Xi＇an 710048 Shaanxi China

To the issues of low efficiency of conflict resolution method in collaborative design, we proposed a method, which is conflict resolution about collaborative design based on grid *** uses the grid services from the current design points, uses the method of retrospective thinking to find the conflict point by detecting, and then uses the corresponding method to resolve the conflict point according to the conflict characteristic, after that carried on the conflict detection again. If there is still the conflict, resolve the conflict point again, until the conflict no longer exists. This method combines various traditional resolution methods, makes full use of the grid idle high-performance large-scale sharing resources. With this method the collaborative design conflict resolution cost reduced and the conflict resolution efficiency was raised. And then the problem which is not handled completely was then solved, so that the conflict resolution Quality was guaranteed.

关键词： grid services collaborative design conflict resolution conflict characteristic conflict detection

Comparison of visual performance between conventional LASIK and wavefront-guided LASIK with iris-registration

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Chinese Medical Journal 2008年第2期121卷 137-142页

作者： zhang jing zhou Yue-hua WANG Ning-li LI Rui Ophthalmic Center Beijing Tongren Hospital Capital MedicalUniversity Beijing 100730 China

Background Laser in situ keratomileusis （LASIK） has become an efficient and commonly performed procedure to reduce refractive errors. In order to further increase the postoperative visual quality, the wavefront-guided refractive surgery has been a research hotspot in customized surgery. This study was conducted to compare the visual acuity, higher-order aberration, and contrast sensitivity of wavefront-guided LASIK with iris-registration and conventional LASIK. Methods Two hundred and eleven myopic eyes of 109 patients were enrolled in this prospective study and randomly divided into two groups： the wavefront-guided LASIK （wg LASIK） group （94 eyes） and conventional LASIK group （117 eyes）. A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square （RMS） of higher order aberrations with 6.0 mm pupil size, and Optec 6500 visual function instrument was used to measure contrast sensitivity （CS） under 5 spatial frequencies before and after surgery in both groups.Results The uncorrected visual acuity （UCVA） and the mean spherical equivalent （SE） in wg LASIK group were significantly better than those in conventional LASIK （UCVA, z=2.339, P=0.019; SE, t=2.838, P=0.005） at 3 months after surgery. Moreover, the increase in Z3^-3, Z3^1, Z3^3, Z4^0, Z5^-1, Z5^1 Z5^-5 and Z6^-6 in wg LASIK group was statistically smaller than that in conventional LASIK group （P〈0.05）. In wg LASIK group, eyes with a higher amount of the preoperative RMS of the higher order aberrations （RMSh≥0.30μm） showed a statistically lower increase （13.5%） than those in conventional LASIK group at 3 months after surgery （33.3%）（P=0.004）. And the values of 4th order spherical aberration （4thSA） and the root mean square of 6th order aberration （RMS6） in wg LASIK group were significantly lower than those in conventional group in eyes which had higher preoperative astigmatism （≥1.0D）（4thSA, P=0.03; RMS6, P=0.02）. Wg LASIK group showed better CS values than the correspon

关键词： aberration contrast sensitivity visual performance keratomileusis, laser in situ

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气膜孔附近粒子沉积特性的数值研究

航空动力学报 2014年第9期29卷 2166-2173页

作者：周君辉张靖周南京航空航天大学能源与动力学院南京210016

研究了气膜孔附近的粒子运动与沉积特性,重点研究了粒子直径和气膜出流吹风比对粒子运动与沉积特性的影响.基于EI-Batsh粒子沉积模型,考虑了粒子的黏附/反弹和离去机制,编制了相应的粒子沉积计算模块集成在Fluent软件中,并利用相关实验... 详细信息

研究了气膜孔附近的粒子运动与沉积特性,重点研究了粒子直径和气膜出流吹风比对粒子运动与沉积特性的影响.基于EI-Batsh粒子沉积模型,考虑了粒子的黏附/反弹和离去机制,编制了相应的粒子沉积计算模块集成在Fluent软件中,并利用相关实验数据对该计算方法进行了验证.结果表明:1,2μm直径粒子沉积率随吹风比增大而增大;3,4μm直径粒子沉积率则随吹风比增大而减小.1μm直径粒子易受气膜出流卵形涡对的卷吸作用而沉积于相邻气膜孔之间区域,当吹风比为2时粒子沉积率比吹风比为0时高约5倍;5μm直径粒子运动轨迹受气膜出流影响较小.总体沉积率随吹风比升高而不断降低,吹风比为2时总体沉积率比吹风比为0时减小1.7%.

关键词：气-固两相流动沉积模型沉积特性气膜孔吹风比

Console形气膜孔改善冷却效率的数值研究

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航空动力学报 2008年第10期23卷 1772-1777页

作者：姚玉张靖周周楠南京航空航天大学能源与动力学院南京210016

运用剪应力输运湍流模型对Console形孔的气膜冷却结构,在不同吹风比下的气膜冷却效率的分布进行了数值研究;并在保持冷气入口相同开孔率的条件下,将其与圆形和缝形气膜孔的冷却效率进行比较.结果表明:随着吹风比的增加,Console形气膜孔... 详细信息

运用剪应力输运湍流模型对Console形孔的气膜冷却结构,在不同吹风比下的气膜冷却效率的分布进行了数值研究;并在保持冷气入口相同开孔率的条件下,将其与圆形和缝形气膜孔的冷却效率进行比较.结果表明:随着吹风比的增加,Console形气膜孔的冷却效率也在增加;在相同吹风比条件下,Console形孔的冷却效率较圆形孔高,较缝形孔低;但在小吹风比时,基本与缝形孔的冷却效率相当.

关键词： Console形孔气膜冷却数值计算

模化比对直升机用红外抑制器红外辐射特性的影响

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航空动力学报 2008年第2期23卷 221-226页

作者：单勇张靖周南京航空航天大学能源与动力学院南京210016

对波瓣喷管-弯曲混合管构成的直升机用红外抑制器壁面和尾焰的红外辐射特性进行了一系列的数值研究,旨在将三维流场数值计算、壁温计算与红外辐射计算结合起来综合分析抑制器红外辐射特性,与相关实验数据的对比验证表明计算结果与实验... 详细信息

对波瓣喷管-弯曲混合管构成的直升机用红外抑制器壁面和尾焰的红外辐射特性进行了一系列的数值研究,旨在将三维流场数值计算、壁温计算与红外辐射计算结合起来综合分析抑制器红外辐射特性,与相关实验数据的对比验证表明计算结果与实验结果仅相差15%左右,且红外辐射强度空间分布规律一致;通过对不同缩比模型的数值计算,揭示了模化比对壁面及尾焰的红外辐射特性的影响规律:(1)几何相似的红外抑制器在主流入口速度、温度相同时,壁面红外辐射强度与几何模化比的2次方成正比;(2)尾焰红外辐射强度与几何模化比的2.32次方成正比.

关键词：航空、航天推进系统红外抑制器红外辐射数值计算逆向蒙特卡罗法模化比

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涡扇排气系统结构参数对排气声压级影响

推进技术 2010年第3期31卷 309-313,319页

作者：单勇张靖周南京航空航天大学能源与动力学院江苏南京210016

基于三维CFD和宽带噪声模型,对不同结构的涡扇排气系统流场和出口声压场分布展开数值计算与分析,获得涵道比、波瓣强迫混合器穿透比和混合段长径比对排气出口声压级的影响规律。数值结果表明:排气系统出口声压级分布与径向速度梯度相对... 详细信息

基于三维CFD和宽带噪声模型,对不同结构的涡扇排气系统流场和出口声压场分布展开数值计算与分析,获得涵道比、波瓣强迫混合器穿透比和混合段长径比对排气出口声压级的影响规律。数值结果表明:排气系统出口声压级分布与径向速度梯度相对大小分布一致,排气出口速度梯度的减小可以降低排气噪声。涵道比在0.5～3.0,长径比在1～2之间,排气系统涵道比和排气混合段长径比的增加可以降低喷管出口平均噪声声压级;在相同涵道比下,波瓣强迫混合器穿透比的增加,出口平均噪声声压级先大幅减小后缓慢增加。

关键词：涡扇发动机波瓣强迫混合器声压级数值计算

致密孔阵气膜冷却绝热温比和对流换热系数的数值研究

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航空动力学报 2009年第6期24卷 1229-1235页

作者：谢浩张靖周南京师范大学动力工程学院南京210042 南京航空航天大学能源与动力学院南京210016

采用数值模拟方法研究了气膜孔叉排方式下孔间距和吹风比对致密孔阵气膜冷却绝热温比和对流换热系数的影响.结果表明:减小相邻孔间距与孔径比或增加吹风比,平均壁面温度就越低,且温度分布更为均匀,绝热温比提高,热侧壁面平均换热系数也... 详细信息

采用数值模拟方法研究了气膜孔叉排方式下孔间距和吹风比对致密孔阵气膜冷却绝热温比和对流换热系数的影响.结果表明:减小相邻孔间距与孔径比或增加吹风比,平均壁面温度就越低,且温度分布更为均匀,绝热温比提高,热侧壁面平均换热系数也随之增大;相对于增加气膜孔阵的密集程度而言,吹风比的增加所带来的绝热温比改善和对流换热系数增加幅度略有减弱.特别是当吹风比大于1以后,吹风比的影响程度比较微弱.

关键词：气膜冷却绝热温比对流换热数值模拟