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Aeroacoustic and aerodynamic optimization of propeller blades

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Chinese Journal of Aeronautics 2020年第3期33卷 826-839页

作者： Peixun YU jiahui peng Junqiang BAI Xiao HAN Xiang SONG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China

It is of great significance to develop a high-efficiency and low-noise propeller optimization method for new-generation propeller aircraft *** with free form deformation method,dynamic mesh interpolation technology,optimization algorithm,surrogate model,aerodynamic calculation and aeroacoustic prediction model module,the integrated aerodynamic and aeroacoustic design method of propeller is *** optimization design for the six-blade propeller is carried *** non-reduction in efficiency,thrust coefficient and the minimum of aerodynamic noise is treated as the optimization design *** spatial vorticity distribution of the propeller before and after the design is also analyzed by using unsteady computational fluid dynamics *** results show that the optimized propeller can effectively reduce the aerodynamic noise *** maximum total sound pressure level can be reduced by 5 dB without reducing its aerodynamic *** developed method has good application potential in low-noise optimization design of propeller and other rotating machinery.

关键词： Aeroacoustic Aerodynamic Dynamic mesh interpolation technology Free form deformation method Optimization algorithm Propeller Sound pressure level Surrogate model

Grindability, Grading and Wettability of Recycled Plaste

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Transactions of Tianjin University 2016年第5期22卷 480-485页

作者： Li Zhixin peng jiahui Zhao Haixin Qiu Xingxing Zhao Min College of Material Science and Engineering Chongqing University Chongqing 400045 China Chong Qing Jianda Building Material Co. Ltd. Chongqing 400030 China Department of Civil Engineering Nanyang Institute of Technology Nanyang 473004 China

The changes of grindability, grading and wettability of recycled plaster(R-P)and the mechanisms of these changes were studied by using vickers hardness, particle size distribution(PSD), scanning electron microscope(SEM) and nitrogen adsorption porosimetry to reveal that R-P was obviously different from plaster of Paris(POP). At the same milling time, R-P had the characteristics of high specific surface area, fine particle diameter and uneven size distribution compared with POP, so R-P possessed both good grindability and poor grading. The water absorption, dissolution rate and mass loss in dry-wet cycle of the hardened recycled gypsum(hardened RG) increased, while the water saturated strength and dry-wet cycle strength decreased significantly compared with the hardened virgin gypsum(hardened VG). Therefore, poor wettability could be seen in R-P. The analyses indicated that the changes of grindability and grading could be attributed to the reduction in hardness and the increase in the porosity of hardened RG and that the poor wettability of R-P was caused by the increase of large pores and the changes of microstructure of hardened RG.

关键词： recycled plaster grindability grading wettability

The Mechanism of the Formation and Transformation of Ettringite

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Journal of Wuhan University of Technology(Materials Science) 2006年第3期21卷 158-161页

作者：彭家惠 Department of Building Materials Chongqing University Chongqing 400045 China

The formation and transformation of ettringite were studied by measuring the ion concentration in liquid phase and analyzing the composition in solid phase. The effects of C3A, gypsum lime and C-S-H gel on ettringite formation and transformation were also investigated. The experimental results shuw, that, when gypsum was presented in solid phase, the composition of liquid phase was in favor of ettringite formation. Ettringite formation consisted of three reactions including the formation of [ Al （OH）6 ]^3- octahedral, formation of Ca-Al polyhedra prism in which Ca and Al polyhedra arranged alternately, as well as entrance of SO4^2- into the channel of polyhedra. [ Al （OH）6 ]^3- formation, which was the slowest reaction, controlled ettringite formation. The concentration of AlO2^- was a main factor that influenced ettringite formation. After gypsum in solid phase was consumed, [ SO4^2- ] decreased quickly and [ AlO2^- ] increased, and it was possible that ettringite transformed into hydrated monsulfate calcium aluminate （ be called M in short） in thermodymanics. The rate of transformation was controlled by diffusion of AlO2^- .

关键词： ettringite hydrated monsulfate calcium aluminate stability transform control step

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微纳技术在泡沫混凝土中的应用进展

材料导报 2017年第3期31卷 80-85页

作者：刘晓英肖玉彭家惠重庆大学材料科学与工程学院重庆400045

微纳技术可从多方面提升泡沫混凝土的性能,使二者性能达到完美结合。从泡沫混凝土气孔结构、泡沫混凝土强度、发泡催化剂以及泡沫混凝土电磁屏蔽效应4个方面综述了近年来微纳技术在泡沫混凝土中的应用,分析并展望了泡沫混凝土的前沿技术。

关键词：微纳技术泡沫混凝土表征技术纳米纤维电磁屏蔽

矿物掺合料对聚羧酸减水剂与水泥相容性的影响

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材料导报 2017年第12期31卷 115-120页

作者：李志坤彭家惠杨再富重庆大学材料科学与工程学院重庆400045 重庆市建筑科学研究院重庆400016 重庆建工建材物流有限公司重庆401122

高性能减水剂与水泥适应性差会导致混凝土流动性和坍落度损失过快,矿物掺合料将影响高性能减水剂与水泥的相容性。对比研究矿物掺合料种类和掺量对水泥净浆、砂浆和混凝土流动性的影响;采用TOC法测试了矿物掺合料对聚羧酸减水剂吸附量... 详细信息

高性能减水剂与水泥适应性差会导致混凝土流动性和坍落度损失过快,矿物掺合料将影响高性能减水剂与水泥的相容性。对比研究矿物掺合料种类和掺量对水泥净浆、砂浆和混凝土流动性的影响;采用TOC法测试了矿物掺合料对聚羧酸减水剂吸附量的影响;分析了矿物掺合料影响聚羧酸减水剂与水泥相容性的机理。结果表明,粉煤灰和矿渣对提高水泥净浆流动性具有一定的叠加效应,可用胶砂减水率的加权平均值进行量化;硅灰对水泥浆体流动性的不利影响远大于粉煤灰和矿渣的辅助减水分散作用,不利于改善聚羧酸减水剂与水泥的相容性;粉煤灰和矿渣增加聚羧酸减水剂在水泥体系中的吸附量;粉煤灰和矿渣对聚羧酸减水剂在混凝土中的减水分散效果有改善作用但不显著。

关键词：掺合料聚羧酸减水剂叠加效应流动性相容性有效吸附量

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墙体材料绿色度评价体系应用实例

新型建筑材料 2008年第7期35卷 4-6页

作者：龚平彭家惠长江大学城市建设学院湖北荆州434023 重庆大学材料科学与工程学院重庆400044

利用已构建的墙体材料绿色度评价体系,选取12种常用墙材进行绿色度评价分析,结果显示模型的评价结果与墙体材料的实际状况是一致的,具有较强的科学性和实用性,并参考评价结果,划分了墙体材料绿色度等级。

关键词：墙体材料绿色度评价体系应用

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墙体材料绿色度评价模型研究

新型建筑材料 2006年第9期33卷 28-32页

作者：龚平彭家惠重庆大学材料科学与工程学院长江大学城市建设学院湖北荆州434023

根据生命周期评价体系和模糊数学层次分析方法,分析了墙体材料生命周期各阶段环境影响因素,建立了影响指标的层次结构,计算出各指标的权重,构造了一个多种因素影响下的墙体材料绿色度定量化综合评价模型。

关键词：墙体材料绿色度生命周期层次分析法

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矿渣改性硬石膏基胶结材水化硬化研究

同济大学学报（自然科学版） 2009年第7期37卷 934-937,959页

作者：彭家惠张建新白冷李青重庆大学国家镁合金材料工程技术研究中心重庆400030 重庆大学材料科学与工程学院重庆400030

通过硬石膏水化率、水化温升、液相离子浓度测定,结合宏观性能试验,对硬石膏基胶结材水化硬化历程,硫酸盐激发剂作用机理,矿渣对硬石膏的改性作用等进行了研究.结果表明:硫酸盐促进硬石膏溶解,提高液相浓度和过饱和度,加快二水石膏晶体... 详细信息

通过硬石膏水化率、水化温升、液相离子浓度测定,结合宏观性能试验,对硬石膏基胶结材水化硬化历程,硫酸盐激发剂作用机理,矿渣对硬石膏的改性作用等进行了研究.结果表明:硫酸盐促进硬石膏溶解,提高液相浓度和过饱和度,加快二水石膏晶体成核与生长速率;矿渣水化形成钙矾石与水化硅酸钙等水硬性矿物,使硬石膏硬化体强度与耐水性提高,矿渣水化与硬石膏水化相互促进;采用硫酸盐激发、矿渣改性的硬石膏基胶结材具有强度较高、耐水性较好、干缩率较小的特点,其水化硬化经历了快速溶解反应期、水化潜伏期、加速水化期、稳定水化期和缓慢水化期等5个阶段.胶结材凝结时间取决于潜伏期,加速水化期和稳定水化期是硬化体结构致密和强度发展的主要阶段.

关键词：硬石膏硫酸盐矿渣水化硬化

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钙矾石形成机理的研究

硅酸盐学报 2000年第6期28卷 511-515页

作者：彭家惠楼宗汉重庆大学材料科学与工程系重庆400045 浙江大学材料科学与工程系杭州310027

采用液相离子浓度测定与固相物相分析的方法 ,分析了离子浓度变化规律与钙矾石形成的关系 .考察了矿物种类与含量、石灰浓度、二水石膏掺量对钙矾石形成的影响 .结果表明 :钙矾石形成是由 [Al(OH) 6 ] 3 - 八面体 ,铝氧八面体与钙多面... 详细信息

采用液相离子浓度测定与固相物相分析的方法 ,分析了离子浓度变化规律与钙矾石形成的关系 .考察了矿物种类与含量、石灰浓度、二水石膏掺量对钙矾石形成的影响 .结果表明 :钙矾石形成是由 [Al(OH) 6 ] 3 - 八面体 ,铝氧八面体与钙多面体交替排列形成钙铝多面柱与SO42 - 进入柱间沟槽 3个过程串联形成 ,其中速率最慢的 [Al(OH) 6 ] 3 - 形成过程为钙矾石形成的控制步骤 .形成钙矾石诸离子中 ,[AlO- 2 ]最低 ,是影响钙矾石形成速率的最活跃因素 .

关键词：钙矾石液相反应形成机理膨胀自应力水泥