不同进气条件相继增压控制策略的仿真研究

根据结构参数和试验数据建立相继增压系统仿真模型。通过试验与计算结果的对比验证该模型,并采用该模型对相继增压控制策略进行研究。根据试验与计算结果确定相继增压的切换策略为切入压气机的打开或关闭应该晚于涡轮的打开或关闭,避免了压气机的喘振及增压空气由进气管向压气机倒流。压气机延迟打开时间随环境压力的降低而升高,随环境温度的降低而降低,压气机延迟关闭时间随环境压力和温度的降低而降低。高原与标准环境相比,延迟打开时间变长,延迟关闭时间变短。     

基于EGR的二冲程柴油机排放模式切换瞬态过程研究

针对船用低速二冲程柴油机为满足TierⅢ排放法规要求,采用EGR技术导致压气机运行点接近喘振线的问题,引入进排气旁通技术。建立了带EGR与进排气旁通的瞬态仿真系统,模拟分析TierⅢ和TierⅡ模式切换过程。分析结果表明:合理选择切换顺序及延迟时间可避免切换过程中发生气体倒流,维持增压压力稳定。并得到了不同负荷下阀门的最佳切换控制策略。     

压气机动态模型的建立及喘振过程分析

在SIMULINK环境中,建立了压气机动态数学模型。为了模拟压气机喘振和旋转失速现象,压气机特性图被延伸到负流量区域,还考虑到了气体通过压气机的延迟。模拟了压气机的喘振过程,并对压气机压力信号进行FFT变换,检测了压气机喘振。仿真结果表明:模型能预测压气机喘振过程中压力、流量和转速的振荡频率和振幅;压缩系统的转动惯量、稳压室容积等结构参数影响喘振特性;模型动态调节特性好,可用于压气机控制系统模型,具有广泛实用性。     

柴油机相继增压系统仿真研究

随着增压压力的提高,柴油机低工况运行时的性能越来越差,相继增压系统用于改善高增压柴油机低工况性能.在Matlab/Simulink仿真软件环境中,应用计算机仿真方法,建立了相继增压柴油机的"准稳态"数学模型,主要对相继增压系统的动态切换过程进行了模拟,通过仿真计算分析了相继增压系统动态切换过程的影响因素及其对柴油机的影响.     

基于dSPACE的柴油机相继增压系统试验研究

为了加快柴油机相继增压控制系统的开发进度,降低开发成本,选用dSPACE实时仿真平台作为相继增压系统控制原型,在TBD234V12相继增压柴油机试验台上进行了相继增压稳态性能试验和动态切换试验。试验结果表明:基于dSPACE实时仿真平台开发的相继增压控制软件及自制硬件电路可以实现对相继增压系统的有效控制,确定以经济性最优为原则的相继增压切换边界。根据动态切换试验数据,确定TBD234V12柴油机相继增压切换延迟时间合理范围为0.5～1.0s。     

带有进排气旁通的相继增压柴油机的计算分析

建立了带有进排气旁通的相继增压柴油机稳态仿真程序,缸内过程采用充满与排空法,进排气过程采用一维非定常流动模型,选择有限体积法对其进行离散求解。对某船用带有进排气旁通的相继增压柴油机,进行了多组性能模拟计算,结果表明:计算结果与试验数据基本一致;柴油机转速在855～920 r/min时,开启旁通阀,能增加压气机的空气流量,避免喘振,并提高了增压压力,降低了排温,改善了柴油机的大扭矩性能,但柴油机的经济性有少量降低。     

船用柴油机相继增压系统性能研究

柴油机高增压会带来严重的部分工况问题,主要有部分工况热负荷较高和容易造成压气机的喘振．柴油机相继增压有效地解决了高增压柴油机低工况问题：改善了低工况燃油经济性,降低了热负荷、减少了喘振可能性等．     

船用柴油机进排气旁通阀开启工况和控制策略研究

使用相继增压技术可以充分发挥高速、高功率密度船用柴油机的性能优势,但是在相继增压技术的使用过程中,依然存在涡前排温超限和增压器喘振等风险。尤其是在船机推进加载的瞬态过程中,喘振现象的出现会极大地影响加载时间。为了降低上述风险,本文对进排气旁通阀开启工况和控制策略进行了研究。研究结果表明:稳态工况时,开启进排气旁通阀,有利于降低低速外特性工况的涡前排温和烟度;瞬态工况时,开启进排气旁通阀,可以降低增压器喘振风险,从而使瞬态推进加载时间从120秒缩短到30秒。此外,先进的控制策略可以使进排气旁通阀在增压器瞬态切换工况时更精准地发挥降低喘振风险的作用。     

压力畸变对大涵道比涡扇发动机影响仿真

基于部件匹配技术的大涵道比涡扇发动机性能仿真模型和平行压气机模型耦合,实现了可以定量分析压力畸变影响的性能仿真程序。以某大涵道比涡扇发动机为例,开展了压力畸变对其压缩部件(风扇、增压级、高压压气机)的喘振边界、共同工作线、喘振裕度以及发动机推力、耗油率的影响仿真。计算结果表明,压力畸变对喘振裕度的影响主要是使压缩部件喘振边界下移,其共同工作线由于存在压力畸变会产生偏移,但其量级较小。对于大涵道比涡扇发动机,压力畸变对风扇外涵喘振裕度影响最大,对风扇内涵/增压级影响次之,对高压压气机影响最小;压力畸变同时会造成发动机推力下降、耗油率上升。     

一种改善增压天然气发动机动力性的方法及试验验证

分析对比了各种增压方法的优势和劣势,提出向压气机后补气,即利用废气涡轮辅助增压系统(EAS系统)改善动力性的方法,并进行台架和整车试验验证。通过分析不同补气压力对发动机性能的影响,得到影响动力性的主要参数是进气压力;补气后喘振趋势增加,合理控制补气速率可以避免喘振。研究结果表明:此方法使发动机低速最大转矩提升率达50%,最大转矩转速向低速移动至900r/min(原机1 200r/min);补气后整车的起步、加速、爬坡性能也得到显著改善。     

Coexisting phenomena of surge and rotating stall in an axial flow compressor

The unsteady inner flow structure of a single-stage axial flow compressor under the coexisting conditions of surge and rotating stall was experimentally investigated via detailed measurements of the unsteady characteristics and the internal flow velocity fluctuations. The main relevant feature of the tested compressor is a shock tube with a capacity tank connected in series to the compressor outlet through slits and a concentric duplex pipe： surge and rotating stall can both be generated by connecting the shock tube. Research attention is focused on the unsteady behavior of a rotating stall during the surge cycle. The size of the rotating stall cell during the recovery process of an irregular surge cycle was experimentally determined by the circumferential flow velocity fluctuations ahead of the rotor blade. The results suggested that the size of the rotating stall cell at the switching point of the performance curve between large and small cycles is considered to be the key parameter in determining the following surge cycle. In addition, the surge cycle is largely influenced by the unsteady behavior of the rotating stall cell.     

燃气轮机压气机喘振监测方法研究

压气机喘振是一种对燃气轮机安全运行具有严重破坏作用的不稳定流动。在研究某燃气轮机控制系统的过程中发现,其控制逻辑中没有针对压气机喘振的控制策略。为了保证燃气轮机安全运行,避免发生喘振对燃气轮机造成破坏,在现有测点基础上研究了在燃气轮机控制系统中增加压气机喘振监测的方法。     

并联离心压缩机防喘振控制系统的研究及应用

文中介绍了新研制的四台并联运行的煤气离心压缩机组的防振控制系统所采用和防喘振控制方法,并对并联离心压缩机机组的防振控制系统的原理、功能及在煤气压缩站的应用作了描述。     

Coordination control strategy for the air management of heavy vehicle fuel cell engine

Air supply system is an important subsystem in the fuel cell engine with strongly non-linear and coupling interactions. There are strong coupling problems between air flow and pressure in the air supply system, such as the air compressor and electronic throttle opening. This paper introduces a novel coordination control strategy for the air supply system of high power fuel cell engine in heavy truck. It consists of feed-forward and internal model decoupling control (IMC) with tracking an optimized working line of centrifugal air compressor. The strategy can maintain good control effect for model matching and model mismatching with robustness. The working efficiency of the centrifugal air compressor could be significantly increased and avoid the phenomenon of surge by the coordination control strategy. At the same time, the output current of fuel cell engine can meet the load requirement which has the short response time and good follow effect.     

燃气轮机压气机喘振及其控制算法

压气机是燃气轮机的三大部件之一,它运行的安全、高效对燃气轮机性能至关重要。本文扼要地介绍了压气机喘振的影响因素,分析了压气机的性能曲线和喘振线;在此基础上针对压气机某一种喘振控制策略,分析其各种控制设定曲线和控制算法。通过以上两方面的介绍,希望对燃气轮机压气机的喘振防治有所帮助。     

Coexisting state of surge and rotating stall in a two-stage axial flow compressor using a double-phase-locked averaging technique

The interaction between surge and rotating stall in an axial flow compressor was investigated from the viewpoint of an unsteady inner flow structure. The aim of this study was to identify the key factor that determines the switching phenomenon of a surge cycle. The main feature of the tested compressor is a shock tube connected in series to the compressor outlet through a diaphragm, slits, and a concentric duplex pipe: this system allows surge and rotating stall to be generated by connecting the shock tube with the compressor, or enables the compression plane wave injection. The unsteady characteristics and the internal flow velocity fluctuations were measured in detail, and the stall cell structure was averaged and visualized along the movement of the operation point under a coexisting state of surge. A coefficient of the cell scale fluctuation was calculated using the result of the averaging, and it confirmed that the processes of inner flow structure change differed from each other according to the next cycle of the surge. The result suggests that the key factor that determines the next cycle is the transformation of the internal flow structure, particularly between the stall cell and the entire circumferential stall, in both the recovering and stalling processes.     

The effect of variable stator on performance of a highly loaded tandem axial flow compressor stage

Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds.Considering the high aerodynamic load effects and structural concerns in the design process,it is possible to obtain higher pressure ratios compared to conventional compressors.However,it must be noted that imposing higher aerodynamic loads results in higher loss coefficients and deteriorates the overall performance.To avoid the loss increase,the boundary layer quality must be studied carefully over the blade suction surface.Employment of advanced shaped airfoils (like CDAs),slotted blades or other boundary layer control methods has helped the designers to use higher aerodynamic loads on compressor blades.Tandem cascade is a passive boundary layer control method,which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads.In fact,the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade's suction side.Also,in comparison to the single blade stators,tandem variable stators have more degrees of freedom,and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance.In the current study,a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage.Following,this design is numerically investigated using a CFD code and the stage characteristic map is reported.Also,the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed.To validate the CFD method,another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.     

叶轮压缩系统喘振的主动控制

为了克服传统防喘振控制方法中以缩小压缩机实际工作范围为代价实现稳定运行的弊病，详细分析了压缩机出口紧联控制阀的工作状况并将其作为主动控制的动作机构，将平衡级压缩机的概念引入二阶MG喘振模型。在此基础上，运用反步递推非线性控制方法设计了叶轮压缩机系统喘振的主动控制。结果表明，对叶轮压缩系统施加主动控制，使压缩机在喘振线附近的效率最高点及压升较高区工作，从而增大了工作范围。     

瞬态EGR对柴油机低温燃烧切换平顺性影响

针对传统燃烧(CDC)与低温燃烧(LTC)双模式柴油机在燃烧模式切换过程中出现的平均指示压力(IMEP)波动、发动机工作平顺性差的问题,基于自主设计开发的单缸柴油机,进行了燃烧模式切换过程瞬态废气再循环(EGR)影响研究.研究表明:燃烧模式切换过程中EGR率变化与燃油喷射变化不同步是造成IMEP波动的主要原因,在1100 r/min、等IMEP为0.6 MPa的LTC负荷上限CDC-LTC的直接切换过程中,EGR响应滞后约22个循环,造成IMEP波动率达到12.82%;采用EGR预控制可以实现EGR与喷油控制的优化匹配,IMEP波动率下降至3.17%,有效改善了切换过程中发动机平顺性.