【作者】 杨传雷；

【导师】 王银燕；

【作者基本信息】 哈尔滨工程大学 ， 动力机械及工程， 2011， 博士

【摘要】 相继增压是改善中高速大功率高增压柴油机低工况性能最为有效的方法,可以有效地扩大柴油机运行范围、提高经济性、减少排放,但是,如果切换点和切换延迟时间等参数选择不当,在动态切换中,容易导致压气机喘振、增压器超速、燃烧排放恶化等问题。为了解决相继增压系统切换过程中可能出现的喘振现象,本文将压气机喘振主动控制技术应用至相继增压系统防喘振控制中,设计了相继增压喘振主动控制系统。结果表明,控制系统可以较好地抑制相继增压系统切换过程出现的喘振现象,为相继增压系统切换的平稳性控制及其安全运行提供了新思路。本文主要研究内容如下：1.涡轮增压器压气机稳态性能试验。根据涡轮增压器压气机稳态性能试验和相继增压系统切换试验的要求,将增压器试验台与相继增压柴油机试验台相结合设计了相继增压热动力试验台,采用燃烧器系统代替大功率柴油机进行相继增压技术的研究,涡轮进口参数柔性可调,更易于控制相继增压系统的工作状态。试验台可以在外循环和自循环模式下进行由3台涡轮增压器构成的不同结构形式的相继增压系统的相关试验,也可以对单台涡轮增压器进行稳态性能试验和动态特性试验。对试验台运行原理、总体结构设计和测控系统设计进行详细研究,进行了增压器压气机稳态性能试验,为试验台自循环切换仿真提供数据支持。2.增压器压气机喘振现象研究。建立了单台涡轮增压器构成的热动力系统仿真模型,对压气机喘振过程中的流量和压力参数变化特征进行分析,找出判断压气机进入喘振的参数及其特征。基于相继增压热动力试验台进行了压气机喘振试验研究,掌握了压气机出口容腔容积和转速对喘振周期的影响规律,利用频谱分析方法和小波分析方法对压气机喘振先兆信号进行了有效的确认,制定了压气机喘振定量判别标准。基于dSPACE实时仿真平台和LabVIEW测试平台进行了压气机喘振主动控制硬件在环仿真,利用模糊控制算法设计了喘振主动控制系统的快速控制原型,为相继增压防喘振控制算法奠定了基础。3.相继增压系统动态切换过程研究。建立了相继增压热动力系统仿真模型,在不同切入延迟时间和不同切出延迟时间以及不同容腔容积的工况下,对切入过程和切出过程进行仿真研究,得出了相继增压系统切换过程的变化规律,并利用相继增压热动力试验台进行了验证。仿真和试验结果表明,大小涡轮相继增压系统中,大增压器作为基本增压器时,切入延迟时间的设置裕度较宽;小增压器作为基本增压器时,切入延迟时间设置裕度较小。切出过程中,空气阀也应迟于燃气阀关闭,切出延迟时间过短,受控压气机将发生严重喘振；切出延迟时间过长,将引起受控压气机倒流。由于空气阀关闭时,增压器仍具有一定转速,受控压气机一定程度的喘振不可避免,但合理的切出延迟时间可以有效降低喘振强度。4.相继增压喘振主动控制系统设计。通过对相继增压系统动态切换特性的研究,制定了相继增压喘振主动控制方案,对切换过程可能出现的喘振现象进行抑制,提高相继增压切换过程的平稳性和安全性。喘振主动控制系统以STM32F103单片机为控制核心,运用μC/OS-Ⅱ嵌入式操作系统为架构进行多任务设计,选用放气阀作为主动控制执行机构对喘振现象进行控制。试验表明,该喘振主动控制系统可以有效抑制相继增压系统切换过程中的喘振现象,提高相继增压系统的性能,证明了控制器软硬件设计的合理性。更多还原

【Abstract】 Sequential turbocharging technology is the most effective way to improve performance for turbocharged diesel engine, particularly at low load. It can expand operation range, improve economic performance and reduce emissions for diesel engine. However, if the switching point and switching delay time is not appropriate, it is easy to cause compressor surge, turbocharger exceed limited speed, combustion become deteriorate and so on. In order to restrain sequential turbocharging system surge phenomenon in switching process, compressor surge active control technology was applied to anti-surge control in sequential turbocharging system, sequential turbocharging anti-surge control system was developed. Experiment results show that surge active control system can inhibit the spread of surge that caused by sequential turbocharging system switching, it offer a new idea to improve the stationarity and safety for sequential turbocharging system. The main contents of this dissertation are as follows:1. Investigation of the turbocharger compressor steady performance. Sequential turbocharging thermal power test bed was designed and constructed according to the requirements of compressor steady performance and sequential turbocharging switching experiment based on turbocharger test rig and sequential turbocharging diesel engine test bed. The test bed used the combustor to replace the high-power diesel engine to study the sequential turbocharging system. It is easy to adjust turbine inlet parameters flexibly, to control working status, to study the overall performance of the sequential turbocharging system. The test bed can work under circulation mode and blow off mode, it can undertake sequential turbocharging test that is composed of three turbochargers in different structure, it also can carry out single turbocharger performance test including steady and dynamic characteristics. This paper make some research about its working principle, overall structure and measurement and control system in detail, the compressor steady performance experiment was carried out based on the test bed, which supplied experiment data for the test bed circulation mode simulation.2. Study on turbocharger compressor surge. The thermal power system simulation model including single turbocharger was established based on Greitzer compression system model. The dynamic characteristics of compressor mass flow and outlet pressure parameters in surging process were analysed to find out parameters or parameters characteristic which can predict oncoming compressor surge. Compressor surging experiment was carried out based on sequential turbocharging test rig, the compressor surge law versus rotational speed and plenum volume was investigated, spectrum analysis and wavelet analysis were applied to validate the surge precursor signal, the quantitative criterion to judge compressor surge was built. Compressor surge active control hardware-in-the-loop-simulation will be carried out based on dSPACE real-time simulation system and LabVIEW measurement system. Fuzzy control algorithm was applied to develop rapid control prototype which make a basis for sequential turbocharging anti-surge control algorithm.3. Investigation to sequential turbocharging system dynamic switching process. Sequential turbocharging thermal power system simulation model was established to study the law of switching process in different switching delay time and different plenum volume. And the relevant experiments were carried out to validate the simulated results. The results show that the large turbocharger as basic turbocharger, the entering delay time have a greater margin; the small one as basic turbocharger, the entering delay time margin is small in unequal size sequential turbocharging system. The sequential turbocharging system exiting experiment show that exhaust valve should be closed before the air valve, ifnot, the controlled compressor would be in deep surge. If the exiting delay time is short, controlled compressor will be in deep surge; if the time is long, the controlled compressor will be in backflow. It is inevitable that the controlled compressor would be in surge state in exiting process due to the turbocharger keep rotate state when air valve was closed, but it can reduce the surge intension to set reasonable exiting delay time. Meanwhile, the volume size of the surge tank has significant influence for dynamic characteristics of the sequential turbocharging system switching process. It should be taken into account the engine exhaust pipeline impact capacity to the booster compressor system dynamic characteristics in turbocharging system design and matching.4. Development of sequential turbocharging surge active control system. The surge active control system used blow-off valve as control actuator, surge controller software and hardware were designed based on STM32F103 micro-processor andμC/OS-Ⅱembedded real-time operating system. Control system acquires turbocharger rotational speed, compressor outlet pressure and compressor mass flow signal, fuzzy control algorithm was designed based on hardware in the loop simulation control prototype. The transplant method ofμC/OS-Ⅱand realization of fuzzy algorithm were introduced in detail. The test results show that the control system can realize the coming surge signal and inhibit the surge spread. It improved the sequential turbocharging system switching stationarity and safety.更多还原