扩压叶栅中格尼襟翼的气动作用与应用

首先研究了二维扩压叶栅中叶片尾缘格尼襟翼对叶片的气动作用,分析了襟翼的高度、安装位置2个参数对叶栅气动性能的影响。结果表明,格尼襟翼能明显提高翼型升力,但阻力也有所增加。接着基于二维叶栅计算获得的最佳襟翼高度和安装位置,将格尼襟翼应用于轴流风扇叶片上,研究其对风扇性能的影响。结果表明,襟翼明显增大了风扇气流转折角,提高风扇的压升,在流量小于设计流量(Q=1.0)时,襟翼风扇总压效率与原始风扇效率相差甚微,而在设计点处,襟翼风扇效率比原始风扇效率高出1%,且当风扇流量大于设计流量时,襟翼风扇与原始风扇总压效率间的差距逐渐扩大,当相对流量Q=1.5时,襟翼风扇总压效率比原始风扇效率高6%。     

离心压气机进口无叶段长度及范围研究

采用NUMECA数值软件计算研究了离心压气机无叶扩压段长度对叶片径向扩压器的影响,以及无叶扩压段长度范围选定。结果表明,在同一进口条件下,无叶扩压段越长,扩压器性能越低;无叶扩压段内气流角与进口状态、无叶段长度与进口半径尺寸变化无关,仅随气流流动距离变化而变化;无叶扩压段的长度无量纲范围为子午高度的0.47～0.93之间,其内流动的气流角与进口位置角度几乎一致。     

基于Fluent的进气流量校准试验装置扩压段设计

为研究扩压段在大扩张角条件下不同导流结构的气动性能，结合某进气流量校准装置扩压段设计要求，利用Fluent软件对多种扩压段导流结构进行数值模拟，以流阻及流场均匀性进行方案选择。以长隔板形式的扩压段方案为基础进行进一步优化设计，经计算分析，等环面积方案具有更好的气动性能。     

汽轮机扩压调节阀的流体力学研究

对于汽轮机而言调节阀是非常重要的组成部分,文中对扩压调节阀进行详细的流体力学分析研究,得出不同类型扩压调节阀的使用范围。     

前缘小叶片对高负荷扩压叶栅性能的影响

针对压气机叶栅角区流动易分离的特点,提出一种在叶栅前缘安装小叶片来抑制角区分离的新型流动控制方法。在利用叶栅试验数据确认数值模拟的可靠性后,对不同攻角下安装小叶片前后叶栅的流场特性进行了数值研究。结果表明:在-6°到9°攻角范围内小叶片改善了扩压叶栅的气动性能,使得总压损失减小,静压升增大。小叶片能使叶栅角区前缘分离点后移,角区分离线后的反流区面积减小,改善了角区流动;更多的流体汇聚到中间叶高,增强叶中部载荷,提高了叶栅的扩压能力。     

基于FLUENT的核心机试车台扩压段设计

为了研究扩压段的扩压性能,以某核心机试车台进气系统为研究对象,提出不同全包角的扩压段设计方案。利用Flue nt软件对扩压段设计方案进行数值模拟,获取不同方案下的流场特性,以出口压力损失和气体分离现象来评选最优方案。经过初步计算,扩压段的压力损失小,随着全包角的增加,扩压段内发生气体分离,筒壁附近形成旋涡,扩压段出口流场品质下降。     

某型无人机进气道扩压器设计与优化

依据喷气发动机喉道扩压段设计方法,通过给定的设计参数,初步设计扩压段方案,采用CFD方法对扩压段性能进行仿真分析。通过调整喉道位置和面积、出口面积等参数;优化扩压段结构参数。研究调整扩压比、改变喉道位置对进气道性能的影响规律,通过仿真分析验证该方法设计的扩压段的有效性。     

某小型涡喷发动机扩压轮结构可靠性分析

以扩压轮的材料参数为控制变量,考虑扩压轮工作温度和离心力的耦合作用,基于响应面法,计算了某无人机用涡喷发动机的压气机扩压轮的结构可靠性,得到扩压轮的可靠性指标,判断其可靠性水平。计算时,编制接口程序调用ANSYS软件进行强度分析,实现可靠性计算的自动化,提高了分析效率。这种响应面法和ANSYS软件相结合的计算思路,可为其他热端旋转部件的可靠性分析提供借鉴。     

用外扩隔板改进扩压叶栅非二维度的尝试

在本文平面扩压叶栅实验中,反映中部截面非二维度的轴向密流相对增量17.8%,加装平行隔板后改进为15.1%,隔板稍稍外扩可又改进为11.0%;但再加大外扩又使这增量回升,即非二维度反而加大。也比较了无隔板时与最佳隔板外扩角时的叶栅攻角特性。     

基于气动反问题的扩压叶栅优化设计

采用扩压叶栅气动反问题的方法,通过选择较优的叶型表面压力系数分布,经过有限步数的叶型修正,获得对应气动目标的新叶型。结果表明:采用Head边界层厚度计算方法,并结合试验设计方法求解出较优的压力系数分布具有可行性。本文采用"弹性模型"修改叶型的方法,设计出了满足要求的叶型,表明该叶型修改方法是成功的,同时表明本文建立的反问题求解程序不仅求解速度快,而且具有较好的实用性以及可靠性。     

风洞大开角段法兰载荷分析

大开角扩散段在风洞回路中有着非常广泛的应用,其在跨超声速风洞中具有重要作用。以风洞大开角扩散段法兰联接为背景,根据压力容器国家标准中有关法兰设计的理论,结合风洞大开角扩散段法兰结构的特点,对该类法兰的载荷进行了分析,给出了载荷及其作用位置的计算公式。     

地铁和隧道风机合理选型及扩压器设计

通过描述地铁隧道风机的几种选型方案来说明地铁和隧道风机的合理选型以及扩压器的设计.     

Simulation of the fluidic features for diffuser/nozzle involved in a PZT-based valveless micropump

PZT-based valveless micropump is a microactuator that can be used for controlling and delivering tiny amounts of fluids, and diffuser/nozzle plays an important role when this type of micropump drives the fluid flowing along a specific direction. In this paper, a numerical model of micropump has been proposed, and the fluidic properties of diffuser/nozzle have been simulated with ANSYS. With the method of finite-element analysis, the increased pressure drop between inlet and outlet of diffuser/nozzle induces the increment of flow rate in both diffuser and nozzle simultaneously, but the increasing rate of diffuser is faster than that of nozzle. The L/R, ratio of L（length of cone pipe） and R （radius of minimal cross section of cone pipe） plays an important role in fluidic performance of diffuser and nozzle as well, and the mean flow rate will decrease with increment of L/R. The mean flow rate reaches its peak value when L/R with the value of 10 regardless the divergence angle of diffuser or nozzle. The simulation results in-dicate that the fluidic properties of diffuser/nozzle can be defined by its geometric structure, and accordingly determine the efficiency of micropump.     

Simulation and optimization of a piezoelectric micropump for medical applications

We designed a valveless micropump excited by a piezoelectric actuator for medical applications. The complete electric–fluid–solid coupling model is built upon using ANSYS software (Canonsburg, PA) to investigate the behaviors of the micropump. The effects of the geometrical dimensions on the micropump characteristics and its efficiency are analyzed. The simulation results show that there is an optimal thickness of the piezoelectric layer to obtain a large pump flow, and that this optimal thickness is affected by the material and the thickness of the pump membrane. To enhance the performance of the micropump, some important diffuser parameters, such as the diffuser length, the diffuser angle, and the neck width, should be optimized. However, the variations of the diffuser’s geometrical dimensions do not affect the optimal thickness of the piezoelectric layer.     

不对称出口导流器的射流式喷灌泵优化研究

为改善射流式喷灌泵的性能,提高泵的效率。本文设计了一种有2个出口的不对称导流器,可以加快泵内的气液混合与分离。通过正交试验和数值模拟方法,得到叶轮与导流器中截面多方案的空气体积分布云图,分析其气液混合与流动规律,研究导流器出口1角度θ、导流器出口2角度α和基圆直径D3对喷灌泵性能的影响,并对数值计算结果进行极差分析。研究结果得出方案4的导流器几何参数较为合理,并进行样机试验。样机试验证明:在额定工况下,泵的效率为68.86%,比国家标准值提高7.6%,达到设计要求。     

生物芯片压电微流体泵扩散管液体流量效率分析

微型扩散管是生物芯片压电微流体泵最重要的部件。它的流量效率是微流体泵关键技术之一。本文对矩形截面的微型扩散管流动进行无量纲分析 ,并采用CFD软件FLUENT对微型扩散管液体三维流动进行大量的数值实验。计算表明 ,微扩散管流量与扩散管结构几何参数 ,压强差 ,液体性质密切相关 ,并得到扩散管流量效率随无量纲参数 (雷诺数、长宽比、厚宽比和扩散角 )的变化规律和最佳流量效率的设计参数范围     

离心风机低稠度扩压器气动性能及噪声特性的试验研究

对一高速离心风机低稠度扩压器的气动与噪声特性进行了试验研究。结果表明,在很宽的运行工况范围内,设计良好的低稠度扩压器静压恢复系数是无叶扩压器的5~7倍。设计低稠度扩压器时,应避免过大正冲角或负冲角,在0°~1.5°范围内比较合适,大的负冲角有利于降低风机的气动噪声。合适的叶栅稠度有利于提高扩压器性能,稠度为0.7时的气动性能最好,小的叶栅稠度有利于降低风机气动噪声。     

驻室抽气压缩机及其与风洞性能相关性研究

为了研究驻室抽气压缩机及其与风洞性能的相关性,对E71-3离心压缩机进行了性能试验,并进行了驻室抽气性能测试。试验结果表明:(1)E71-3离心压缩机实测最高压比4.516,设计点多变效率81.8%,达到了设计要求。(2)风洞运行总压升高,压缩机多变效率降低。(3)风洞试验段Ma=0.9~1.1时,驻室抽气量对风洞模型区梯度的影响不大,但驻室抽气量超过4%后风洞马赫数均方根偏差明显增大;压缩机稳定在中等转速、适量抽气量的工况,且入口流量调节阀全开,风洞流场品质较好,运行成本最低。     

刀刃角与岩石节理倾角对盘型滚刀破岩效率的影响

为了研究节理倾角与刀刃角对滚刀破岩效率的影响,运用ABAQUS有限元分析软件,采用Druker-Prager弹塑性本构模型模拟岩石材料,使用不同刀刃角的滚刀对不同节理倾角的岩石进行滚切加工,并结合破岩比能理论研究破岩效率,以破岩比能最小为依据确定不同节理倾角下的最优刀刃角。研究结果表明:不论倾角如何,节理层处的岩石破碎效果优于其他地方的破碎效果;在节理倾角为0°和30°时,滚刀的破岩比能呈波动的趋势,而且最优刀刃角为60°;在节理倾角为60°时,最优刀刃角为45°~50°;在节理倾角为90°时,最优刀刃角为40°~45°;随着节理倾角的增加,最优刀刃角呈不断减小趋势。该研究结果可为不同地质条件下盾构施工时的刀具选型提供一定的理论依据。     

Analyzing the shape parameter effects on the performance of the mixed-flow fan using CFD & Factorial design

Fans are representative turbo-machinery widely used for ventilation throughout the industrial world. Recently, as the importance of energy saving has been magnified with the fans, the demand for the fans with high efficiency and performance has been increasing. The representative method for enhancing the performance includes design optimization; in practice, fan performance can be improved by changing the shape parameters such as those of meridional plane, impeller, and diffuser. Before optimizing the efficient design, a process of screening to select important design parameters is essential. The present study aimed to analyze the effects of mixed-flow fans’ shape parameters on fan performance (static pressure and fan static efficiency) and derive optimum models based on the results. In this study, the shape parameters considered in the impeller domain are as follows: tip clearance, number of blades, beta angle of Leading edge (LE) in the blade, and beta angle of Trailing edge (TE) in the blade. The shape parameters considered in the diffuser domain are as follows: meridional length of the Guide vane (GV), number of GV, beta angle of LE in the GV and beta angle of TE in the GV. The effects of individual shape parameters were analyzed using the CFD (Computational fluid dynamic) and DOE (Design of experiments) methods. The reliability of CFD was verified through the comparison between preliminary fan model’s experiment results and CFD results, and screening processes were implemented through 2^4-1 fractional factorial design. From the analysis of DOE results, it could be seen that the tip clearance and the number of blades in the impeller domain greatly affected the fan performance, and the beta angle of TE at the GV in the diffuser domain greatly affected the fan performance. Finally, the optimum models with improved fan performance were created using linear regression equations derived from 2^4-1 fractional factorial design.