Hybrid URANS/LES Method of Flow Fields in Axial-flow Compressor Rotor Rotor

Accurate and efficient prediction of the aerodynamic performance and flow details of axial-flow com-pressors is of great engineering application value for the aerodynamic design and flow control of axial-flow compres-sors.In this work,a delayed detached eddy simulation method is developed and applied to numerically simulate the tur-bulent channel flow and the aerodynamic performance of NASA Rotor 35.Several acceleration techniques including parallel implementation are also used to speed up the iteration convergence.The mean velocity distribution and Reyn-olds stress distribution in the boundary layer of turbulent channel flow and the aerodynamic performance curve of NASA Rotor 35 are predicted.The good agreement between the present delayed detached eddy simulation results and the available direct numerical simulation results or experimental data confirms the effectiveness of the developed meth-od in the accurate and efficient prediction of complex flow in turbomachinery.

Effect of blade tip winglet on the performance of a highly loaded transonic compressor rotor

The tip leakage flow has an important influence on the performance of transonic com- pressor. Blade tip winglet has been proved to be an effective method to control the tip leakage flow in compressor, while the physical mechanisms of blade tip winglet have been poorly understood. A numerical study for a highly loaded transonic compressor rotor has been conducted to understand the effect of varying the location of blade tip wing]et on the performance of the rotor. Two kinds of tip winglet were designed and investigated. The effects of blade tip winglet on the compressor over- all performance, stability and tip flow structure were presented and discussed, It is found that the interaction of the tip winglet with the flow in the tip region is different when the winglet is located at suction-side or pressure-side of the blade tip. Results indicate that the suction-side winglet （SW） is ineffective to improve the performance of compressor rotor. In addition, a significant stall range extension equivalent to 33.74% with a very small penalty in efficiency can be obtained by the pressure-side winglet （PW）. An attempt has been made to explain the fundamental mechanisms of blade tip winglet in detail.

Aerodynamic Sweeping Study and Design for Transonic Compressor Rotor blades

The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor rotor.The baseline to be modified and swept is a designed well efficient transonic single rotor compressor. The first part of the present study is concerning the sweep effect with straight leading edge.In this case fixing the hub section the swept blade is formed by tilting the leading edge with whole blade forwards and backwards axially.The second part is to use an optimization strategy with simple gradient-based optimum-searching method and multi-section blade parameterization technique to search and generate an optimal swept rotor with curved arbitrary leading edge.Its adiabatic efficiency is a little bit greater than that of the reference un-swept rotor.

Numerical Investigation of the Unsteady Flow in a Transonic Compressor with Curved Rotors

The unsteady 3D flow fields in a single-stage transonic compressor under designed conditions are simulated numerically to investigate the effects of the curved rotors on the stage performance and the aerodynamic interaction between the blade rows. The results show that, compared to the compressor with unurved rotors, the compressor under scrutiny acquires remarkable increases in efficiency with significantly reduced amplitudes of the time-dependent fluctuation. The amplitude of the pressure fluctuation around the stator leading edge decreases at both endwalls, but increases at the mid-span in the curved rotors. The pressure fluctuation near the stator leading edge, therefore, becomes more uniform in the radial direction of this compressor. Except for the leading edge area, the pressure fluctuatinn amplitude declines remarkably in the tip region of stator surface downstream of the curved rotor, but hardly changes in the middle and at the hub.

Geometry of screw compressor rotors and their tools

This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools.It describes the details of lobe shape specification,and focuses on a new lobe profile,which yields a larger cross-sectional area and shorter sealing lines resulting in higher delivery rates for the same tip speed.A well proven mathematical model was used to determine the optimum profile,compressor housing size,and compressor ports to achieve the superior compressors.

Numerical Simulation of Rotor Clocking Effect in a Low-Speed Compressor

Two-dimensional (2D) unsteady numerical simulation has been applied to studythe effect of the variation in relative circumferential positions of rotors on the performance of alow speed compressor. The result shows that the variation will change the relative position ofupstream rotor wake to the downstream rotor as well as the periodic and turbulent velocityfluctuations on the airfoils. When the upstream rotor wake impinges upon the leading edge of thedownstream rotor, the corresponding stage efficiency will be higher; when the upstream wake istransferred into the mid-passage of the downstream rotor, the corresponding stage efficiency will belower. The proper configuration of the relative position of rotors will cause obvious reduction inthe unsteady aerodynamic effect on the second rotor airfoils and improve the aerodynamic performanceof blades.

Flow Field Improvement by Bowed Stator Stages in a Compressor with Different Axial Gaps Under Near Stall Condition

The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of the straight stator stages are investigated and compared to those of the bowed stator stages. The results show that using bowed stator stages could alleviate the flow separation at both upper and low corners of the suction surface and the endwalls, and decrease the losses along the flow passage as well as the outlet flow angle. As the rotor/stator axial gap decreases, although the diffusion capacity of the compressor increases obviously, the outlet flow field in the straight stator stages deteriorates quickly. By contrast, little changes occur in the bowed stator stages, indicating that as the rotor/stator axial gap decreases, improved performance is achieved in the bowed stator stages.

Principle and Thermodynamic Process of the Compressor of Composite Gear Teeth

The compressor of composite gear teeth is a new type of rotor compressor withpartial built-in compression process. Analysis of its thermodynamic process indicates that thebuilt-in process is incomplete. The thermodynamic process of the compressor of composite gear teethcan be considered as five processes; the suction process, the isometric process, the compressionprocess, the pressure-balance process at high pressure and low pressure gas, and discharge process.Here, it is necessary to explain further the pressure-balance process. The pressure-balance processis isometric process. It is found that the isometric process of gas in chamber A whose capacity is83 percent of total work volume can be eliminated basically through extending the discharge port toconnect early the discharge port with the chamber B. By the above-mentioned method, the loss ofenergy will be reduced.

车用柴油机高压比宽流量增压器研制

目的 对于单级高压比宽流量增压器,为适应发动机强化指标,进行一系列的改进设计。方法 利用仿真设计与试验相结合的方法,对高海拔环境应用增压器进行改进设计。通过理论推导,确定压气机及涡轮的气动性能优化设计方法,开展高稳定裕度转子轴承系统设计方法研究与验证。结果 匹配高压比宽流量增压器的发动机与原机相比,高原功率恢复了17%,发动机排气温度降低了7%,增压器转速降低了13%。结论 在原机的基础上设计了压比为4.6的宽流量高性能涡轮增压器,成功实现了高压比宽流量增压器的设计,满足了发动机平原、高原不同环境的运行需求。

基于流固耦合的压气机转子叶片非同步振动分析

压气机转子叶片非同步振动是近年来发现的一类新气动弹性问题,表现为叶片振动频率与转频不同步且具有锁频现象,严重影响航空发动机的可靠性和运行安全,目前对其产生机理并不完全清楚.为了深入研究压气机内不稳定流动与叶片非同步振动之间的耦合机制,基于时间推进的方法建立了多级压气机转子叶片全环的双向流固耦合模型,数值研究了刚性叶片与非同步振动柔性叶片的非定常流场、气流激励频率和结构响应特征,揭示了压气机转子叶片非同步振动的流固耦合机制.结果表明:近失速工况下,转子叶尖吸力面径向分离涡的周期性脱落及再附过程是导致叶尖压力剧烈波动的主要原因,其3倍谐波激励频率与转子一阶弯曲固有频率接近,提供了叶片非同步振动的初始气流激励源.叶片非同步振动发生时,位移响应表现为等幅值的极限环特征,振动以一阶弯曲模态主导,径向分离涡产生的非整数倍气流激励频率及其谐波频率最终锁定为叶片一阶弯曲固有频率,非同步振动的运动胁迫使得相邻通道叶尖流场周向趋于一致.研究成果及对叶片非同步振动流固耦合机制的认识可为压气机内部不稳定流动诱发的叶片振动失效分析提供有益参考.

某离心压气机转子叶尖流场测试及可视化分析

对壁面动态压力传感器阵列测试技术进行了研究,并将该技术应用于某离心压气机转子叶尖的动态流场测试中,获取了大量的动态流场测试数据。采用锁相技术和线性插值方法对测试数据进行了处理和分析,并采用数据可视化技术将动态数据转化成压力分布云图,从云图中可以清楚看出离心压气机不同工作状态下转子叶尖的压力变化,有助于分析转子叶尖处泄漏流、前缘溢流以及泄漏流和分流叶片前缘的相互作用。转子叶尖流场测试及可视化分析结果可以为压气机性能验证和数值模拟方法的修正提供重要的技术支撑。

大型焊接式轴流压缩机转子弯曲控制技术研究

文章详细论述了某焊接式轴流压缩机转子制造工艺流程。通过对空心部位特点进行分析,制定出稳定可靠的加工方案,重点分析压缩机转子在加工中的静挠度特性,以及转子焊后偏心控制及修正技术。

轴流压气机叶片表面盐雾颗粒沉积仿真

为研究轴流压气机在运行过程中盐雾颗粒在叶片表面的碰撞点和碰撞量分布,基于拉格朗日离散相(DPM)模型对不同旋转速度、不同盐雾粒径条件下压气机叶片表面盐雾颗粒碰撞状态进行了仿真,获取了压气机叶片表面盐雾颗粒碰撞分布规律;基于压气机轴对称结构开发了叶片表面盐雾碰撞位置及碰撞量的统计软件,对叶片表面盐雾颗粒碰撞情况进行了统计。结果表明:盐雾碰撞位置受压气机通道形状与盐雾颗粒受力大小影响,盐雾颗粒与叶片的碰撞主要发生在叶盆面,叶背面只有少量的盐雾颗粒能够到达;盐雾颗粒在叶片表面沉积的覆盖面积与盐雾颗粒直径呈正相关,在最大状态下且盐雾颗粒直径为5μm时,转子和静子叶盆表面盐雾颗粒沉积的覆盖面积分别为59.3%和55.3%;盐雾颗粒在叶片表面沉积的覆盖面积与压气机转速呈正相关,在慢车状态下且盐雾颗粒直径为5μm时,转子和静子叶盆表面盐雾颗粒沉积的覆盖面积分别为57%和42.9%。

低雷诺数下轴流压气机转子3维流动特性数值模拟

为了探究轴流压气机转子在低雷诺数下的性能及3维流动特性,对跨声速转子压气机Rotor37在地面和高空下的气动性能和内部流场进行了数值模拟。结果表明:在20 km高空下,压气机在近失速点的总压比和绝热效率分别降低了8.0%和5.3%,喘振裕度降低了3.1%;在低雷诺数下,转子吸力面上的流动分离位置会提前掺混且更剧烈,导致分离附面层增加,同时由于吸力面附面层较厚,激波与边界层的作用加强,减小叶表附面层内低能流体向上运动的压力分量,低能流体在离心力的作用下更容易向叶顶附近迁移,这可能是触发转子工作失稳的重要因素;在低雷诺数下,叶片根部吸力面在84%轴向弦长处发生完全分离并形成角涡,在其向叶顶移动的过程中形成脱落涡,角涡和脱落涡面积明显增加,这是引起转子低雷诺数工作效率降低的重要原因之一。

透平压缩机常见振动故障分析与处理方法探讨

当前石油、天然气、化工、矿山等领域均涉及对透平压缩机的有效应用,可为其高效生产提供助力。但长期处于高功率、高速、高压运行状态下,压缩机转子极易在激振力的影响下出现失稳现象,继而增大出现振动故障的概率。为促进压缩机可靠、安全运行,需借助科学措施有效解决振动问题。从透平压缩机常见振动故障分析入手,并提出振动故障处理方法。

螺杆式压缩机转子受力简化计算方法研究

为便于工程人员或设计人员进行螺杆式压缩机转子受力计算,满足转子强度校核、轴承选型以及轴承寿命核算要求,提出一种螺杆式压缩机转子受力简化计算方法,并通过计算流体动力学方法进行验证。结果表明:在不同工况下,该简化计算方法对径向力预测的偏差在8.0%以内,个别工况最大偏差为11.4%,轴向力的预测偏差在5.0%以内,简化模型能够满足工程应用的要求。

转子叶顶间隙值及改型对压气机性能影响的数值模拟

为了分析转子叶顶间隙值和改型对压气机性能的影响,以典型轴流跨声速压气机NASA stage 35为对象,对不同叶顶间隙值的压气机进行数值模拟。结果表明:叶顶间隙增大并且泄漏流强度提高,会导致脱体激波位置前移,转子吸力面激波作用位置后移,前缘溢流现象减弱,叶尖泄漏涡与激波作用增强,间隙区域涡量增加,靠近前缘的涡核向下游移动,但附面层与激波之间的作用减弱;不同叶顶间隙值的压气机失速机制不同,在小间隙下压气机失速是由叶尖泄漏涡和转子吸力面附面层分离共同作用引起的,在大间隙下压气机失速是由叶尖泄漏涡引起的;在研究的变化范围内,叶顶间隙值为0.50τ时,压气机性能最好,峰值效率和稳定裕度分别提高了0.16%和2.39%;将最优间隙改型成平行扩张式和正弦波间隙后,压气机性能提高,脱体激波后移,叶尖泄漏涡与激波作用程度减弱,转子吸力面附面层分离减弱,改型间隙能够减少叶片制作材料,减轻发动机质量。

车载滑片式压缩机数值建模及其性能研究

由于对滑片式压缩机几何优化的研究有限,大多数受几何结构影响的流动和泄漏机制尚未完全揭示。为此提出一种新型车载滑片式压缩机,其设有密封减震垫片以减小磨损摩擦,进、排气口采用异面布置且进气口端面为月牙形结构,以改善腔内流动。结合动网格技术,选取RNG κ-ε湍流模型,采用Pumplinx对滑动叶片数量、叶片尖端间隙高度进行数值研究,并搭建压缩机试验台架进行试验验证。结果表明:随着滑片数量的增多,出口温度和定转子啮合间隙泄漏减小,质量流量增加;定转子啮合间隙高度从0.01 mm增大到0.05 mm时,质量流量和容积效率分别降低了11.46%和6.69%,而排气温度增加了45.8 K,间隙泄漏量增大了1.13倍。

10 kWe空间堆闭式布雷顿系统驱动单元设计

针对空间反应堆要求能量密度高和长寿命等特点,提出一种以气体箔片轴承作为支承,高效率径流式叶轮作为驱动的离心式压气机设计方案。以特定流量、压力、功率和效率作为设计依据,进行叶轮的气动设计,得到高效率压气机和高效率径流式涡轮模型。基于有限元法,对径向气箔轴承的顶箔变形分别采用欧拉梁和厚板模型进行表达,并结合Reynolds方程进行求解,厚板模型的计算结果准确反映了顶箔沿轴向的变形,由此得到的气膜厚度、气膜压力和承载力更加符合实际,在厚板模型基础上求得轴承动态刚度和阻尼系数更为合理。选取合理的轴承模型获取了转子系统的临界转速和闭式布雷顿系统的最低起飞转速,并由线性轴心轨迹得知转子系统在额定工况具有更好的稳定性。最后对止推箔片轴承的承载特性进行了分析,提出了装配注意事项,为10 kWe空间堆闭式布雷顿系统驱动单元样机研制提供了理论指导。

荒煤气压缩机运行故障的原因分析与防控措施

介绍了新疆广汇集团哈密广汇环保科技有限公司40万t/a荒煤气制乙二醇项目配套的荒煤气压缩机高压缸,分析了其在运行中出现转子叶轮损坏、隔板腐蚀的原因,并制定了有效的防控措施,为荒煤气压缩机组及整个装置的长周期运行打下坚实基础。