Aeroelastic Analysis and Optimization of High-aspect-ratio Composite Forward-swept Wings

In order to analyze the effects of forward-swept angle and skin ply-orientation on the static and dynamic aeroelastic characteristics, the aeroelastic modeling and calculation for high-aspect-ratio composite wings with different forward-swept angles and skin ply-orientation are performed. This paper presents the results of a design study aiming to optimize wings with typical forward-swept angles and skin ply-orientation in an aeroelastic way by using the genetic/sensitivity-based hybrid algorithm. Under the conditions of satiated multiple constraints including strength, displacements, divergence speeds and flutter speeds, the studies are carried out in a bid to minimize the structural weight of a wing with the lay-up thicknesses of wing components as design variabies. In addition, the effects of the power of spanwise variation function of lay-up thicknesses of skins and iugs on the optimized weights are also analyzed.

Stiffness Distribution and Aeroelastic Performance Optimization of High-Aspect-Ratio Wings

The relationship between stiffness distribution and aeroelastic performance for a beam-frame model and a3-D model is investigated based on aeroelastic optimization of global stiffness design for high-aspect-ratio wings.The sensitivity information of wing spanwise stiffness distribution with respect to the twist angle at wing tip,the vertical displacement at wing tip,and the flutter speed are obtained using a sensitivity method for both models.Then the relationship between stiffness distribution and aeroelastic performance is summarized to guide the design procedure.By using the genetic/sensitivity-based hybrid algorithm,an optimal solution satisfying the strength,aeroelastic and manufacturing constraints is obtained.It is found that the summarized guidance is well consistent with the optimal solution,thus providing a valuable design advice with efficiency.The study also shows that the aeroelastic-optimization-based global stiffness design procedure can obtain the optimal solution under multiple constraints with high efficiency and precision,thereby having a strong application value in engineering.

Investigation of Optimal Split Ratio of 6-Slot/2-pole High Speed Permanent Magnet Motor with Toroidal Winding

Split ratio,i.e.the ratio of stator inner diameter to outer diameter,has a closed relationship with electromagnetic performance of permanent magnet(PM)motors.In this paper,the toroidal windings with short end-winding axial length are employed in the 6-slot/2-pole(6s/2p)PM motor for high speed applications.The split ratio is optimized together with the ratio of inner slot to outer slot area,i.e.slot ratio,considering stator total loss(stator iron loss and copper loss).In addition,the influence of maximum stator iron flux density and tooth-tip on the optimal split ratio,slot ratio,and average torque is investigated.The analytical predictions show that when the slot ratio is 0.5,the maximum torque can be achieved,and the optimal split ratio increases with the decrease of slot ratio,as confirmed by the finite element(FE)analyses.Finally,some of predicted results are verified by the measured results of 6s/2p prototype motor with 0.5 slot ratio.

高强度混凝土结构施工技术及性能优化

结合工程案例,介绍了高强度混凝土材料的特性表现,从强度提升、收缩变形、抗渗性能、抗裂性能等方面论述了高强度混凝土结构的优化策略,从配合设计、搅拌工艺、浇筑及养护技术等方面探讨了施工技术的改进措施,从而保证高强度混凝土结构的整体性能和施工质量。

Oscillation and Conversion Performance of Double-Float Wave Energy Converter

In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency(capture width ratio).Based on the potential flow theory and the higher-order boundary element method(HOBEM), we constructed a threedimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO's damping coefficient for the double-float WEC's capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs.

Reagent optimization for on-line simultaneous polarographic determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of anextremely large excess of Zn^(2+)

Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).

Analysis of torque transmitting behavior and wheel slip prevention control during regenerative braking for high speed EMU trains

The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability,improving the adhesion utilization,and achieving deep energy recovery.There remain technical challenges mainly because of the nonlinear,uncertain,and varying features of wheel-rail contact conditions.This research analyzes the torque transmitting behavior during regenerative braking,and proposes a novel methodology to detect the wheel-rail adhesion stability.Then,applications to the wheel slip prevention during braking are investigated,and the optimal slip ratio control scheme is proposed,which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control.The proposed methodology achieves the optimal braking performancewithoutthewheel-railcontactinformation.Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.

Optimization on the High Precision 3D Seismic Acquisition Parameters in Leijia Tight Sandstone Oil Area

The main targets of seismic exploration research in Leijia carbonatite tight sandstone oil area of Liaohe depression are thin reservoirs prediction and minor faults identification, which is one of the important representatives of complex exploration objects in Liaohe depression. High precision 3D seismic exploration has significantly improved the ability of thin reservoirs prediction and minor faults identification of this area. Reducing the cost of high precision 3D seismic exploration through optimizing the acquisition parameters is very important for the next step exploration and development of Liaohe depression and similar areas. Based on high precision 3D seismic acquisition data in Leijia tight sandstone oil area, multiple sub-geometries are obtained with different bin sizes, different folds, different aspect ratio, different line intervals by extracting receiver points and shot points, and PSTM processing is performed respectively, obtained PSTM datasets of the sub-geometries, extract time slices, amplitude slices along the layer, coherent slices and so on. We evaluate the data results of the sub-geometries from the aspects of signal-to-noise ratio, thin reservoirs resolution, acquisition footprint and so on. Considering the exploration cost and data effect of each sub-geometry, the optimal direction of the main parameters of high precision seismic exploration in Liaohe depression is put forward, and the acquisition effect of adjacent area by the optimized parameters is given.

Investigation on Noise Control Technology of Ultra-High Expansion Ratio Turbine

Aerodynamic noise control is one of the key technologies in the development of stealth technology of torpedo. The noise producing mechanism in an ultra-high expansion ratio turbine with partial admission were discussed. Wide wakes originating from non-outlet region between elliptical nozzles,circumferential non-uniformity owing to partial admission design and complex shock system formed in narrow space between nozzles and rotors are three main sources of aerodynamic noise in this turbine. Thus,two kinds of aerodynamic noise control methods were put forward,namely adding axial gap between the nozzle and rotor,nozzle-down,bilateral repair and trailing edge blowing. Steady annulus simulation results showed that the aerodynamic noise was significantly reduced by more than 10 dB after optimization,which had little impact on the aerodynamic performance of the turbine.

基于响应面回归模型的纤维混凝土力学性能分析

为研究玄武岩纤维和纤维素纤维掺量对混杂纤维轻骨料高强混凝土抗压强度、抗折强度和劈裂抗拉强度的影响,构建响应面回归模型,对比分析其力学试验实测值和预测值,并结合渴求函数获得混凝土优化配合比.结果表明:此回归模型有效且可信度高,可用于分析试验结果;两种纤维交互作用、水灰比与纤维素纤维交互作用对抗压强度、抗折强度、劈裂抗拉强度影响显著;模型预测最优水灰比为0.30,纤维素纤维掺量为0.90 kg/m3,玄武岩纤维掺量为4.00 kg/m3,强度预测值与试验值间相对误差绝对值均小于5%,该回归模型可为混杂纤维轻骨料高强混凝土的配合比多目标优化提供参考.

某酒店制冷机房运行策略优化

对华东地区某酒店制冷机房运行策略进行了优化,利用能耗模拟软件对多种运行方案进行了仿真分析。结果表明:原方案仅对冷水泵采用变频控制,制冷机房能效比为4.62;优化方案1采取传统变频方式,对冷水泵、冷却水泵、冷却塔风机采用变频控制,制冷机房能效比达到5.32,与原方案相比提升了15.1%;优化方案2通过对冷水机组、冷水泵、冷却水泵、冷却塔风机进行优化控制,制冷机房能效比为5.48,与原方案相比能效比提升了18.6%,且每年可减少约79 t碳排放量,节能效果显著。

低烈度区某超高层塔楼优化分析

超高层建筑由于单塔体量较大,结构经济指标备受关注,寻找最合理结构体系是超高层建筑不断自我迭代更新的主题。高烈度区和低烈度区塔楼控制方向完全不同,着重介绍优化过程以寻找低烈度区超高层塔楼的最优结构。以某位于低烈度6度区的建筑高度250m超高层塔楼为例,根据塔楼初步方案确定控制指标为刚重比和剪重比,以控制指标为目标进行附加质量和自重的迭代优化。其次是提高结构刚度,核心筒尺寸根据竖向交通及设备管井已确定,在建筑允许条件下通过柱的不同排布实现了更好的框架刚度贡献;纯混凝土柱重量贡献大于刚度贡献,通过对比叠合柱和型钢柱,选取了更合理的叠合柱截面形式;在低烈度区结构竖向承载满足基本需求而水平刚度不满足规范要求的情况下,通过增加伸臂桁架提高整体刚度;通过分析不同伸臂桁架形式,选取了最有效的伸臂形式。通过降低结构冗余重量和有效提高结构刚度选出最高效结构,且建筑品质优、造价合理。

高容配比光伏电站储能运行方式及其容量配置研究

随着光伏产业的不断发展,高容配比逐步成为光伏电站设计的主流趋势。针对高容配比子阵内部储能优化充、放电策略的问题,文章提出了一种基于工作模式识别的储能运行方式,以实现能量搬移和平抑波动两种非协同的工作目标。综合考虑光伏储能联合系统的发电收益、储能成本、波动特性、典型日类别等信息,构建了以全生命周期净现值最大和平抑波动效果最优为目标的储能容量优化配置数学模型。以东北某大型光伏电站1.8容配比的1 MW光伏子阵作为案例研究对象,优化得到的最佳储能容量为700 kW·h。不同典型日的仿真结果表明,文章所提出的储能运行方式及配置模型可行有效。

某水电站琴键堰体型优化试验研究

琴键堰是一种新型的高效溢流堰,以曲折的堰顶结构来增加溢流前缘总长度,使得其泄流能力远超直线堰。针对某拟建水电站琴键堰泄流能力不足的问题,提出了增加展宽比(L/W)、增加堰高(P)和增加堰高且减少单元数(n)的优化方案,并通过物理模型试验进行验证,得到了满足设计要求的推荐方案。此外,本研究还探讨了水工模型类别(整体及断面模型)和比尺效应对琴键堰泄流能力的影响。通过对比分析优化方案可知:方案M1(展宽比L/W由7.75增至8.88)中,琴键堰泄流能力得到了一定程度的提高,但泄流能力仍不满足设计要求;方案M2(堰高由4.50 m增至6.50 m)和M3(堰高由4.50 m增至6.90 m,单元数由17.5个减至8.5个)中,琴键堰泄流能力显著增加,该两种方案皆可满足设计要求。试验结果表明:与琴键堰整体模型相比,其断面模型测得的泄流能力偏大约6%;对于琴键堰,当模型堰上水头大于2.50 cm时,比尺效应对琴键堰泄流能力的影响可以忽略。

Production optimization in a fractured carbonate reservoir with high producing GOR

The Gas-Oil Ratio(GOR)is a crucial production parameter in oil reservoirs.An increase in GOR results in higher gas production and lower oil production,potentially leading to well shut-ins due to economic infeasibility.This study focuses on a real fractured oil field that requires urgent production operations to reduce the producing GOR.In this study,the static model for the field was developed using commercial software,involving steps such as data collection,fault modeling,meshing,and statistical analysis to prepare for dynamic simulation.The dynamic model incorporates geometry,gridding,and rock properties from the static model,utilizing a dual-porosity approach for the naturally fractured reservoir and the Peng-Robinson equation for fluid phase behavior.Initial reservoir conditions,production history,and rock-fluid interactions were defined,with relative permeability curves indicating a water-wet reservoir and low critical gas saturation affecting the GOR.To better understand the relationship between reservoir and production parameters,a detailed sensitivity analysis was performed using the Response Surface Methodology(RSM).Following the sensitivity analysis,a history matching process was conducted using the Designed Exploration and Controlled Evolution(DECE)optimizer to validate the model for future forecasts.Six operational scenarios were defined to decrease the production GOR and enhance final recovery from the field.The results indicate that the water injection scenario is effective in preventing the GOR increase by maintaining reservoir pressure,thereby sustaining production over a longer period.This scenario also improves oil recovery by approximately 6%compared to the base case.Finally,optimization was carried out using the DECE optimizer for each scenario to fine-tune the operational parameters.The goal was to maximize oil revenue for each scenario during the optimization process.This study stands out as one of the few that provides a comprehensive analysis of production behavior and development planning for a real fractured reservoir with high producing GOR.

一种抑制高速电机低次电流谐波的调制方法

针对高速永磁同步电机低载波比、数字控制延时所引起的电流谐波较大的问题,提出一种抑制低次电流谐波的改进型特定次谐波消除调制方法。首先,对该调制方法的调制波形原理和数字实现特点进行分析,建立新的电压谐波方程和开关角求解方程;其次,以电流总谐波失真为目标优化函数,研究了调制比和载波比对开关角分布、电流谐波含量的影响;最后,以三相高速永磁同步电机为研究对象,搭建系统仿真模型对所提调制方法进行验证。验证结果表明,通过与特定次谐波消除调制方式相比,所提调制方法计算量更少,可以提高输出脉宽调制波形的对称性,具有更优的低次电流谐波抑制能力。

高效制冷站在某汽车工厂涂装车间的应用研究

从高效制冷站的基本概念及设计理念出发,以高效供需匹配为导向,给出了高效制冷站的设计要点及其在汽车工厂涂装车间的应用案例。案例实际运行数据表明,该制冷站的全年运行平均能效比(EER)达到6.5,远高于T/CECS 1100—2022《高效空调制冷机房评价标准》一级要求,实现节能50%以上。

酵母强化大曲接种量优化及其生产应用

为提高泥坑浓香型白酒中高温大曲综合生产性能,该研究从中高温大曲中分离筛选菌株,采用2,3,5-氯化三苯基四氮唑(TCC)初筛,发酵实验复筛,获得发酵性能良好的酵母菌,并以Z综合得分为响应值,通过单因素试验及响应面试验对筛选菌株接种量进行优化,并将其用于强化大曲生产。结果表明,共分离纯化出8株菌株,其中,3株产酒性能良好的菌株Y1、Y2、Y3,其最佳接种量分别为7.0×10^(8)CFU/mL、3.0×10^(8)CFU/mL、1.5×10^(8)CFU/mL,在此优化复配条件下,主成分Z综合得分为513,所生产的强化大曲发酵力、糖化力和液化力分别为3.46 g/(g·72 h)、994 mg/(g·h)、1.12 g/(g·h),比优化前提高了424%、6.7%和5.7%。

基于C形梁质量控制的国产T300级碳纤维匹配性研究

以大长径比C形梁为研究对象,针对其表面质量、厚度、外形轮廓、金相分析等问题,制定工艺研究路线。通过比对国产T300级碳纤维织物及单向带预浸料的制造效果,明确了与大长径比、小R结构C形梁相匹配的国产T300级碳纤维预浸料的类型。通过设计直观的研究目标及高效的比对方案,阐明了国产T300级碳纤维单向带预浸料与大长径比C形梁构型的工艺匹配性强,为国产复合材料后续的研究方向提供借鉴,缩短了国产复合材料研究应用的周期。