部分叶高串列扩压器对离心压气机性能的影响

为了保证离心压气机压比同时拓宽其稳定工作范围,将部分叶高概念引入串列扩压器设计中,获得部分叶高串列扩压器,并基于数值方法研究串列叶栅前后排叶片相对周向位置以及前排叶片相对高度对离心压气机与串列扩压器性能的影响.在相对周向位置为30%的串列扩压器基础上,利用不同部分叶高叶片设计串列扩压器前排叶片,获得不同的部分叶高串列扩压器.结果表明:串列叶栅前后排叶片相对周向位置对扩压器的扩压能力以及稳定工作范围有很大影响,当相对周向位置处于20%~30%内时离心压气机的整体性能达到最佳;与原离心压气机相比,当前排叶片相对高度h/B分别为40%和50%时,离心压气机的喘振裕度可分别增加21%和25%,总压比和等熵效率仅下降1%左右.     

部分叶高串列扩压器对离心压气机性能的影响

为了保证离心压气机压比同时拓宽其稳定工作范围,将部分叶高概念引入串列扩压器设计中,获得部分叶高串列扩压器,并基于数值方法研究串列叶栅前后排叶片相对周向位置以及前排叶片相对高度对离心压气机与串列扩压器性能的影响.在相对周向位置为30%的串列扩压器基础上,利用不同部分叶高叶片设计串列扩压器前排叶片,获得不同的部分叶高串列扩压器.结果表明:串列叶栅前后排叶片相对周向位置对扩压器的扩压能力以及稳定工作范围有很大影响,当相对周向位置处于20%~30%内时离心压气机的整体性能达到最佳;与原离心压气机相比,当前排叶片相对高度h/B分别为40%和50%时,离心压气机的喘振裕度可分别增加21%和25%,总压比和等熵效率仅下降1%左右.     

串列叶栅前后排叶片周向相对位置对离心压气机性能的影响

串列叶栅前后排叶片相对位置对串列扩压器的性能有重要影响.根据离心叶轮出口气流参数设计了一离心式串列叶栅扩压器,并利用数值模拟方法在前、后排叶栅周向相对位置分别为10%、20%、30%、40%、50%、60%、70%、80%和90%时对离心压气机级进行了计算和分析,研究周向相对位置变化对离心压气机性能的影响以及作用机理.数值模拟结果表明:随着前后排叶栅周向相对位置变化,后排叶栅前缘滞止高压区相对前排叶栅的位置发生了变化,影响了前排叶栅压力面的压力分布,从而改变了前排叶栅压力分布及大小;当前后排叶栅周向相对位置为30%时,扩压器性能达到最佳,使压气机总压比和等熵效率最大,稳定工作范围增大;前后排叶栅所形成的渐缩通道可抑制后排叶栅吸力面边界层的分离.     

扩压器叶片厚度分布对离心压气机性能的影响

叶片扩压器对离心压气机性能有着重要影响,在某机翼型叶片扩压器的叶片角分布规律保持不变的情况下,调整扩压器叶片的厚度分布,通过流场对比分析扩压器叶片厚度分布对压气机性能的影响。结果表明:扩压器叶片最大厚度分别位于75%和50%弦长位置方案比最大厚度位于25%弦长方案的整级效率提升2. 3%和1. 4%,喘振裕度分别提高了34. 2%和16. 7%。     

离心压气机预旋及扩压器调节扩稳研究

以增压器无叶扩压离心压气机为研究基础,进行了压气机预旋导叶及扩压器设计,对单预旋、固定扩压器及预旋、扩压器耦合调节等不同情况下的离心压气机特性进行了数值分析,研究了进口预旋及扩压器可调的压气机扩稳特征。结果表明:压气机进口预旋在保持压气机最高效率特性基本不变的同时可以使压气机的流量范围拓宽16.7%,叶片式扩压器则可明显提高压气机最高效率约1.7%。在无叶扩压离心压气机的基础上,采用进口预旋和叶片式扩压器耦合调节控制的方法可在拓宽压气机喘振裕度的同时可使压气机工作效率提高约1.2%。     

双列叶栅扩压器几何参数对离心式压气机特性影响的试验研究

近年来,通过在45GP130高压比增压器和320P 增压器上对双列叶栅扩压器的试验研究,作者提出了一些对双列叶栅扩压器的规律性认识。在设计试验中发现。两列叶栅匹配位置、间隙、重叠度、扩压器的中径、弦长比诸参数对压气机性能影响较大。对装有双列叶栅扩压器的320P_4增压器作了与16V280Z 柴油机的匹配试验。试验结果证明,双列叶栅在增压器上的应用是有效的。目前,串联技术应用于离心式压气机叶片扩压器设计,尚无一套成熟的设计方法。本文提供的试验数据可以作为进一步研制双列叶栅扩压器的参考和借鉴。另外,文中还介绍了双列叶栅扩压器的机理、双列与单列叶栅扩压器噪声对比试验。     

离心压气机错排叶栅扩压器性能研究

依据叶片设计的基本理论,在原设计单列圆弧叶栅扩压器的基础上,根据相似准则设计了一种新型的双列错排叶栅扩压器;同时利用NACA叶型又设计了另一种双列错排叶栅扩压器。随后重点对三种扩压器与离心叶轮相连后的结构性能进行了详细的三维粘性数值模拟研究,并对流场中的压力、速度、极限流线和熵分布情况进行了全面的分析。研究结果表明：基于NACA叶型的双列错排叶栅扩压器可以更好地利用叶轮出口的动能,从而提高叶轮-扩压器结构的效率;但若叶栅的叶型设计不合理,则会使总压比降低,效率反而降低,即叶型对错排叶栅扩压器的性能影响较大。     

一种新型叶片扩压器的联合处理方法

以机翼扩压器为研究对象，对某船用涡轮增压离心压气机性能进行数值模拟．首先将扩压器叶片进行低稠度处理，在此基础上再进行叶片根部开槽处理，以研究低稠度与开槽联合处理对整机性能的影响．结果表明：低稠度处理可在全转速范围内拓宽流量范围，但失速边界发生整体右移；低稠度与开槽联合处理能够保持堵塞流量不变时，在全转速范围内增大失速裕度，在进一步拓宽流量范围的同时，解决失速边界偏移问题，可使高转速下稳定工作流量范围甚至超过无叶扩压器的2倍，但同时联合处理也降低了气动性能，仍高于无叶扩压器性能；槽道的径向位置是开槽处理的关键参数，除了影响流量范围大小外，还会使峰值效率点的绝热效率、总压比分别产生近4.0%、1.5%的波动，因而需优先确定．     

叶片安装角对离心压气机扩压器气动性能及失速机理影响研究

为了研究离心压气机扩压器异常叶片对于失速现象的诱发效果,以带有叶扩压器的高速离心压气机为研究对象,通过整体或局部改变扩压器叶片安装角,开展非定常数值模拟研究并与实验结果对比验证,研究叶片安装角改变对离心压气机性能、动态特性以及失速机理的影响规律。研究表明：整体负方向旋转叶片安装角会促使扩压器更加不稳定,旋转角度从-5°到5°,最高效率点对应的质量流量逐渐增大。其中安装角偏转+5°扩压器叶片前缘靠近轮缘壁面发生流动分离,诱使无叶区间产生回流;而偏转-5°扩压器轮毂附近的流动分离主要发生在尾缘,造成扩压器叶片吸力面附近产生大范围回流。单个叶片安装角发生较大偏转(大于10°)时,扩压器比叶轮更早进入失速状态,且失速的机制可能会随着安装角偏移的增大发生改变。     

扩压器稠度对某离心压气机性能的影响

采用数值模拟方法详细分析了楔形扩压器稠度对某高转速、高压比离心压气机性能和内部复杂流动的影响,结果表明,减小扩压器叶片稠度,离心压气机堵塞流量和稳定工况范围都将增加。在大流量工况下,低稠度扩压器具有更好的性能,而小流量工况时,高稠度扩压器将得到更高的压比和效率。     

Design and optimization of a single stage centrifugal compressor for a solar dish-Brayton system

According to the requirements of a solar dish-Brayton system,a centrifugal compressor stage with a minimum total pressure ratio of 5,an adiabatic efficiency above 75% and a surge margin more than 12% needs to be designed.A single stage,which consists of impeller,radial vaned diffuser,90° crossover and two rows of axial stators,was chosen to satisfy this system.To achieve the stage performance,an impeller with a 6:1 total pressure ratio and an adiabatic efficiency of 90% was designed and its preliminary geometry came from an in-house one-dimensional program.Radial vaned diffuser was applied downstream of the impeller.Two rows of axial stators after 90° crossover were added to guide the flow into axial direction.Since jet-wake flow,shockwave and boundary layer separation coexisted in the impeller-diffuser region,optimization on the radius ratio of radial diffuser vane inlet to impeller exit,diffuser vane inlet blade angle and number of diffuser vanes was carried out at design point.Finally,an optimized centrifugal compressor stage fulfilled the high expectations and presented proper performance.Numerical simulation showed that at design point the stage adiabatic efficiency was 79.93% and the total pressure ratio was 5.6.The surge margin was 15%.The performance map including 80%,90% and 100% design speed was also presented.     

The influence of wedge diffuser blade number and divergence angle on the performance of a high pressure ratio centrifugal compressor

Wedge diffuser is widely used in centrifugal compressors due to its high performance and compact size. This paper is aimed to research the influence of wedge diffuser blade number and divergence angle on centrifugal compressor performance. The impact of wedge diffuser blade number on compressor stage performance is investigated, and then the wedge diffusers with different divergence angle are studied by varying diffuser wedge angle and blade number simultaneously. It is found that wedge diffuser with 27 blades could have about 0.8% higher adiabatic efficiency and 0.14 higher total pressure ratio than the wedge diffuser with 19 blades and the best compressor performance is achieved when diffuser divergence angle is 8.3°.These results could give some advices on centrifugal compressor design.     

离心压缩机无叶扩压器的改进新方法

研究了某高压比离心压缩机无叶扩压器的性能，提出在无叶扩压器轮盘侧加装一定高度机翼型导叶的改进方法。结果表明，这种扩压器可以改善其内部流动，提高自身的压力恢复系数和效率，从而改善离心压缩机的整级性能。     

叶片根部倒角对离心叶轮气动性能影响

叶轮是决定离心压气机气动性能的关键因素之一,在保持叶轮设计参数不变的条件下,调整叶根倒角的分布,对比分析叶根倒角对压气机性能的影响.利用Numeca软件对跨声速离心压气机进行全三维稳态流动数值模拟方案分为等半径倒角与变半径倒角两种.结果表明:主叶片后半弦长的倒角是决定压气机气动性能的关键性因素,尾缘倒角比前缘更敏感;根...     

Investigation into the influence of diffuser stagger angles on the flow field and performance of a centrifugal compressor

The performance graphs of a centrifugal compressor under different diffuser stagger angles were measured, and the influence of different stagger angles of vanes on the stage performance as well as flow field was investigated numerically. The results show that the performance graph shifts when the diffuser stagger angle is altered; the influence of different stagger angles of vanes on the flow field inside the centrifugal compressor is great. Large scale vortices appear on the diffuser vane under larger incidence. An optimal diffuser stagger angle should exist at a specified flow rate to make the characteristic of the flow optimized. The incidence corresponding to the highest efficiency is not 0° at the design condition. Translated from Journal of Engineering Thermophysics, 2006, 27(1): 61–64 [译自: 工程热物理学报]     

超临界氦气离心压气机流场分析

设计了一个包含离心叶轮、扩压器和回流器的单级超临界氦气离心压气机,并采用数值模拟方法对设计结果进行了三维数值模拟分析。通过对总特性、叶表压力分布、展向参数分布以及三维流场的分析,得到了高负荷超临界氦气离心压气机各部件内部的典型复杂流动特点。研究结果表明：相比常规工质,超临界氦气离心压气机单级压比较低,但叶轮与扩压器的负荷和级效率较高,且超临界氦气整体流动为亚音流,只在叶片前缘局部出现超音区。     

Investigation of a centrifugal compressor and study of the area ratio and TIP clearance effects on performance

In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and dif- fuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was stud- ied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 mm, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simula- tion at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the effi- ciency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm resulted in 20 percent efficiency decrease.     

Global Search of a Three-dimensional Low Solidity Circular Cascade Diffuser for Centrifugal Blowers by Meta-model Assisted Optimization

A three-dimensional blade of a low solidity circular cascade diffuser in centrifugal blowers is designed by means of a multi-point optimization technique. The optimization aims at improving static pressure coefficient at a design point and at a small flow rate condition. Moreover, a clear definition of secondary flow expressed by positive radial velocity at hub side is taken into consideration in constraints. The number of design parameters for three-dimensional blade reaches to 10 in this study, such as a radial gap, a radial chord length and mean camber angle distribution of the LSD blade with five control points, control point between hub and shroud with two design freedom. Optimization results show clear Pareto front and selected optimum design shows good improvement of pressure rise in diffuser at small flow rate conditions. It is found that three-dimensional blade has advantage to stabilize the secondary flow effect with improving pressure recovery of the low solidity circular cascade diffuser.