共查询到19条相似文献,搜索用时 189 毫秒
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通过仿真软件对某型废气涡轮增压柴油机进行建模,在原机模型基础上分别在涡轮压气机前端和后端加装电动增压器,分析增压柴油机满负荷和25%负荷工况下,电动增压器前置和后置对于涡轮增压器稳态性能的影响以及增压柴油机1800 r/min时,通过时间3 s,使柴油机负荷从25%提升至满负荷的瞬态工况下,电动增压器对涡轮增压器瞬态响应的影响。通过研究表明:稳态时,涡轮增压器压比和效率随柴油机负荷降低而下降,加装电动增压器能够提升进气流量和涡轮增压器压比以及涡轮增压器效率;瞬态时,设定工况下,电动增压器有助于改善增压柴油机涡轮增压器瞬态进气流量、压比、效率以及涡轮压气机转速响应差的问题。 相似文献
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就车用废气涡轮增压柴油机出现的瞬态响应特性变差、适应性系数降低、热负荷增加等问题进行了分析讨论,从结构和使用两方面提出了改进的措施 相似文献
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为了研究生物柴油在柴油发动机上的应用,本文在一台4缸涡轮增压柴油机上进行了生物柴油与0#柴油的排放特性对比试验。测定了试验用生物柴油与0#柴油的理化指标,并在不同负荷下对比分析了生物柴油与0#柴油的排放特性。研究结果表明:试验用生物柴油的大部分理化指标符合《车用柴油》国标要求;与燃用0#柴油相比,燃用生物柴油时发动机的HC和碳烟排放大幅度下降,CO排放在大负荷时略有降低,NOx排放增加。 相似文献
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对某柴油机采用大小涡轮相继增压系统进行了推进特性的稳态及瞬态试验研究。对柴油机分别采用小涡轮增压器、大涡轮增压器以及大小2台涡轮增压器并联3种增压方案进行推进特性的稳态试验,并对试验结果进行了比较分析,确定了该相继增压系统的两个切换工况点分别为40%和80%负荷工况。在各切换工况下进行了阀门不同切换时间的瞬态试验,通过分析切换过程中发动机各性能参数的变化,确定了各阀门的开闭顺序及延迟时间:在40%和80%负荷工况点切换时,阀门VCS滞后阀门VTS开启的最佳时间分别为0.6s和0.4s,阀门VCS滞后阀门VTS关闭的最佳时间均为0.2s。 相似文献
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为探究松油作为柴油机替代燃料的可行性,在定容弹中结合高速摄影技术对松油掺混比例为20%,、40%,和50%,的柴油/松油混合燃料在不同喷射压力及背压下的宏观喷雾特性进行可视化研究;同时基于一台4缸涡轮增压柴油机,研究掺混燃料在不同负荷下的燃烧和排放特性.结果表明:随喷射压力及背压的改变,4种燃料喷雾特性的变化规律一致;相同条件下松油掺混燃料的喷雾锥角、贯穿距及油束面积均比柴油大,且松油掺混比越大,雾化效果越好.在试验负荷范围内,松油掺混燃料的有效燃油消耗率、最大压力升高率比柴油略大;在全负荷工况下50%,掺混燃料的转矩较柴油仅降低2%,表明松油可提供与柴油相当的动力输出.掺混燃料在低负荷时的NO_x、CO和THC排放均高于柴油,中、高负荷时掺混燃料的CO及THC排放低于柴油,NO_x排放与柴油差别不大;通过增加松油掺混比例可以大幅降低碳烟的排放. 相似文献
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在分析涡轮增压发动机低速转矩矩不足和瞬态响应特性较差原因的基础上,提出运用小型涡轮技术、双级增压系统、进气旁通增压系统、排气旁通增压系统、可变喷嘴环流通截面涡轮增压系统、节流阀式涡轮增压系统、双蜗壳通道涡轮增压系统、电子辅助涡轮增压(EAT)系统与涡轮、机械双增压(TSI)系统是改善涡轮增压发动机转矩特性的有效措施。 相似文献
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涡轮增压柴油机的结构参数对瞬态响应特性具有重要影响。通过平均值模型建立柴油机进排气系统的传递函数,利用传递函数的增益与时间常数得到瞬态特性的评估指标。该指标结合试验测得的部分状态参数可用来分析柴油机结构参数如进排气管容积、增压器转动惯量、涡轮通流面积等对瞬态的影响权重,从而为柴油机的改进设计提供指导意义。 相似文献
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S. C. Tripathy M. Kalantar R. Balasubramanian 《Energy Conversion and Management》1992,33(12):1063-1072
Dynamic system analysis is carried out on an isolated electric power system consisting of a wind turbine generator (WTG) and a diesel engine generator (DG). The 150 kW wind turbine generator is operated in parallel with the diesel generator to serve an average load of 350 kW. A comprehensive digital computer model of a hybrid wind-diesel power generation system, including the diesel and wind power dynamics for stability evaluation, is developed. The dynamic performance of the power system and its control logic are studied, using the time domain solution approach. A systematic method of choosing the gain parameter of the wind turbine generator pitch control by the second method of Lyapunov that guarantees stability is presented. The response of the power system with the optimal gain setting to the random load changes has been studied. Analysis of stability has further been explored using the eigenvalue sensitivity technique. 相似文献
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The difference in dynamic behaviour of wind turbines connected to different size networks is analysed for synchronous and induction generators. Modal analysis has been applied to equivalent mechanical models of the wind turbine generator and the grid connection to show the difference in dynamics for a wind turbine generator connected to a large (interconnected) utility network or an (isolated) diesel micro-grid. Frequency domain analysis of these models has been used to quantify the effect of system parameters, such as enhanced drive train damping, diesel governor action and generator slip, on dynamic interaction. It has been shown that for wind turbines connected to a large grid an induction generator can reduce dynamic interaction. In contrast, for an isolated diesel micro-grid the diesel governor response and the compliance of the diesel generator dominate the system's dynamics, and the choice of either generator option for the wind turbine is dictated by other factors. 相似文献
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Large eddy simulation of dynamically controlled wind turbines in an offshore environment 总被引:1,自引:0,他引:1
Accurate modelling of transient wind turbine wakes is an important component in the siting of turbines within wind farms because of wake structures that affect downwind turbine performance and loading. Many current industry tools for modelling these effects are limited to empirically derived predictions. A technique is described for coupling transient wind modelling with an aero‐elastic simulation to dynamically model both turbine operation and wake structures. The important feature of this approach is a turbine model in a flow simulation, which actively responds to transient wind events through the inclusion of controller actions such as blade pitching and regulation of generator torque. The coupled nature of the aero‐elastic/flow simulation also allows recording of load and control data, which permits the analysis of turbine interaction in multiple turbine systems. An aero‐elastic turbine simulation code and a large eddy simulation (LES) solver using an actuator disc model were adapted for this work. Coupling of the codes was implemented with the use of a software framework to transfer data between simulations in a synchronous manner. A computationally efficient simulation was developed with the ability to model turbines exhibiting standard baseline control operating in an offshore environment. Single and multiple wind turbine instances were modelled in a transient flow domain to investigate wake structures and wake interaction effects. Blade loading data were analysed to quantify the increased fluctuating loads on downwind turbines. The results demonstrate the successful implementation of the coupled simulation and quantify the effect of the dynamic‐turbine model. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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小型风力发电机面临的最大难题是其可靠性问题,即大风时的限速保护问题.从能量守恒的角度分析了利用风轮与发电机的功率匹配特性实现风力发电机限速保护的可行性.另外,设计了2台风轮与发电机具有不同匹配特性的300 W/26 V风力发电机,为了使其具有可比性,使用了同样型号的发电机.通过实验测试了风轮的机械输出特性、发电机在输出电压不同时的功率特性和整机的功率输出,实验结果表明,风速12 m/s以下时2台风力机输出功率基本相同,风速12 m/s以上时其中1台随着风速的增加功率不断增加,而另外1台随着风速的增加输出功率不再上升,甚至有点下降,与大风机功率特性相似. 相似文献
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In this paper the dynamics of a small autonomous system, comprising a diesel generator and a wind turbine, are investigated. The analysis is performed both in the frequency and time domain, using simplified models of the system components and taking into account the diesel engine speed governor and the wind turbine pitch controller (for pitch regulated machines). The investigation is extended to include different types of wind turbines, equipped with induction or synchronous generator and using pitch or stall regulation, as well as operation of the wind turbine in an autonomous or infinite system. The objective is to determine the main factors affecting the behaviour of the system and to illustrate the effect of the speed governor and pitch controller settings on the expected performance. Particular emphasis is placed on identifying the main modes of the system and determining their dependence on the controllers' parameters. A comparative assessment of the dynamic characteristics of different types of wind turbines is also included and the operation of the wind turbine in a small system and against an infinite bus is addressed and discussed. 相似文献
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为对比高水头水泵水轮机的转轮加装短叶片前后的能量特性及流动特性,基于SST湍流模型,选取4个具有代表性的水泵及水轮机工况,对有/无短叶片的水泵水轮机进行全流道三维定常计算。数值模拟结果表明,以水泵运行时加装短叶片可抑制脱流与漩涡等二次流现象,降低单个叶片承受的水力载荷,提高转轮进出口、导叶区及蜗壳静压,使泵获得更高的扬程。水轮机运行时添加短叶片可减小转轮出口环量,改善在尾水管内形成的复杂漩涡流,提高其水力效率。相同边界条件下,长短叶片转轮改善了转轮区的流动条件,从而提升了机组的能量特性及水力稳定性。 相似文献