某型增压柴油机排气系统的仿真研究

排气系统设计是否合理对柴油机的性能有着重要影响,为了探求某型增压柴油机采用不同排气系统的优越性,本文以内燃机性能仿真软件GT-Power为平台,建立了工作过程仿真模型,利用试验数据验证了模型的可靠性.柴油机采用脉冲增压系统,针对定压增压系统和MPC增压系统对原机的排气系统进行了重新设计,建立了定压增压系统和MPC增压系统的柴油机模型,并分别对其进行了稳态工作过程计算,着重分析研究了采用不同排气系统对该柴油机性能的影响,为该柴油机排气系统的改进提供了参考依据.     

12V150车用柴油机排气系统研究

介绍了大功率车用柴油机 MPC增压系统的设计思想 ,通过可调式排气管对 1 2 V1 50车用柴油机 MPC增压系统的结构参数进行了优化试验。在此基础上重新设计了 MPC系排气系统 ,试验结果表明该系统改善了发动机低速性能。最后 ,分析了试验中存在的问题并提出改善措施。     

高速增压柴油机增压系统优化设计

本文用广义一维非定常流动计算方法,对高速增压柴油机三脉冲排气系统进行了性能模拟与优化计算,并与优化后的MPC系统作了两种增压方式在排气有用能传递上的对比和特点分析。     

8V165增压中冷柴油机降低热负荷性能改进研究

以提高8V1656增压中冷柴油机低速特征和降低热负荷为目的进行了研究，通过改进增压器并与柴油机合理匹配，增加了空气流量，改善了其低速性能，通过对原MPC排气系统所存在问题的分析，结合性能模拟计算，对MPC排气系统的主要结构尺寸进行了优化设计，有效地降低了柴油机的燃油消耗率和涡轮前排气温度，取得了较好的整机性能指标；为了进一步降低柴油机的热负荷，根据8V165增压中冷柴油机的特点，尝试进行了进排气连通技术的研究，在保证柴油机性能指标的基础上使涡轮前排气温度进一步下降，最终满足了柴油机的使用要求。     

可变几何排气管增压系统与其他增压系统的对比计算研究

为了解决某船用8缸机高低负荷兼顾的问题,提出了1种全新的可变几何排气管增压系统,它通过安装在排气管上的可控阀门来实现增压方式的转换。利用GT-POWER对可变几何排气管增压系统进行了计算研究,根据油耗最优原则找出其阀门开和阀门关之间的切换点在50%负荷;又分别对四脉冲增压系统、PC系统、MPC系统和MIXPC系统进行了计算研究。计算结果表明:在25%、50%、75%、100%负荷,可变几何排气管增压系统的油耗均小于四脉冲增压系统、MPC增压系统和MIXPC增压系统的油耗,扫气系数均大于四脉冲增压系统、MPC增压系统和MIXPC增压系统的扫气系数。     

8V165柴油机应用组合脉冲转换(MPC)增压系统的研究

<正> 1 前言脉冲增压的8V165/155柴油机在额定工况时存在燃油耗率和排温均偏高的缺点,为此作者提出了采用MPC增压系统来代替原脉冲增压的方案,以改善该机的性能并简化其排气系统的结构。作者通过电子计算机进行了多方案模拟计算,优化设计出该机的MPC增压系统方案,并进行了零部件加工和整机试验。在8V165/155柴油机上进行的试验结果表明,在所有的运行工况下,柴油机的功率大幅度提高,燃油耗率和排温也有较大的下降,机械负荷变化不大。通过计算证明增压器的效率有较大幅度的提高。     

可变几何排气管增压系统的模拟试验研究

针对可变几何排气管增压系统在6缸机上的应用效果进行了模拟试验研究,利用原机脉冲增压系统排气管模拟阀门关,用新加工的准定压增压系统排气管模拟阀门开。试验结果表明:在标定工况下准定压增压系统的油耗比脉冲增压系统的油耗降低4.7 g/(kW.h)。原因是当增压方式为准定压增压系统时,在强制排气过程中,排气管内排气平均压力减小,使泵气负功减小,油耗下降。     

可控脉冲增压系统对D6114柴油机性能影响研究

可控脉冲增压系统可以实现气缸相对排气容积的调节,具有兼顾发动机高低转速工况的优势。本文针对D6114ZLQB型柴油机,建立了该发动机可控脉冲增压系统GT-POWER仿真模型,通过不同排气容积条件下发动机性能试验校核了仿真模型。计算研究了不同转速下可控脉冲增压排气系统排气压力波和进气压力变化规律,探讨了脉冲增压系统和准定压增压系统在不同转速下的适应情况。通过仿真计算研究了可控脉冲增压系统对柴油机性能的影响,确定了可变脉冲增压系统的切换边界。     

高背压环境条件下涡轮增压柴油机排气系统适应性研究

本文通过对多脉冲引射排气系统和定压增压排气系统的模拟计算,研究了高背压和高真空环境条件下废气涡轮增压柴油机的排气系统的适应性。结果表明多脉冲引射排气系统对高背压环境条件下的自由废气涡轮增压柴油机并未显示其通常的优越性,而定压增压排气系统却表明具有明显的优点。文章也拟定了4脉冲引射排气系统的模拟计算方法,讨论了多脉冲引射排气系统的排气引射系数对柴油机性能的影响。     

16V190燃气发动机MPC排气系统设计优化

为提升增压器效率,实现降低排气温度的目标,在计算剖析颜巴赫排气系统的基础上,针对颜巴赫机型主要关注排气损失和功率要求,排气总管设计较粗的特点,对国产16V190燃气发动机模件式脉冲转换(modular pulse converter,MPC)排气系统进行设计优化;在满足16V190功率设计要求的前提下,主要从排气管管径设计及排气支管缩口设计对16V190排气管进行对比设计和计算分析,结果表明:优化获得了较低的排温,达到了设计优化的要求。     

乌鲁木齐市某换热站监控系统的设计研究

由于供热系统中用户换热站没有有效的调节装置和根据热负荷的变化进行实时调节的自控系统,影响了乌鲁木齐市的集中供热系统整体效果.根据控制策略分级执行的原则将换热站系统分为：就地监控系统、通信系统以及中心控制系统.对换热站整体结构以及监控系统方案进行了设计,并应用于实际,运行情况良好.     

储能电站作为系统辅助启动电源的建模研究

随着储能技术的发展和储能电站规模的不断增加,系统大停电后可考虑储能电站作为系统辅助启动电源以协助系统的恢复,考虑铅蓄电池、磷酸铁锂电池、全钒液流电池和钠硫电池为主要储能电站电池类型,根据蓄电池组放电功率和放电持续时间的幂次函数关系建立不同电池类型储能电站放电模型,储能电站放电模型和经济模型一起构成系统辅助启动电源模型,进而在系统辅助启动电源模型的基础上,以给定恢复时间内系统恢复的功率最大为目标函数,提出了考虑系统辅助启动电源的黑启动方案优化模型,并通过savnw23节点系统算例验证了储能电站作为系统辅助启动电源的可行性和黑启动方案优化模型的正确性。     

基于神经网络的集中供暖系统约束控制

为提高集中供暖系统的热效率,提出了一种基于神经网络的集中式供暖系统的水阀开合度控制策略,引入了障碍李雅普诺夫函数和一个特殊设计的辅助系统来解决控制系统中出现的输入输出约束的问题。采用了一种神经网络逼近器来在线估计系统模型,解决系统传递模型未知的问题。通过模拟仿真同时测试了所提出系统的性能,与传统PID控制系统进行对比,该系统具有良好的适应性和稳定性,有一定的实用价值。     

Optimisation and techno-economic analysis of autonomous photovoltaic–wind hybrid energy systems in comparison to single photovoltaic and wind systems

A techno-economic analysis for autonomous small scale photovoltaic–wind hybrid energy systems is undertaken for optimisation purposes in the present paper. The answer to the question whether a hybrid photovoltaic–wind or a single photovoltaic or wind system is techno-economically better is also sought. Monthly analysis of 8 year long measured hourly weather data shows that solar and wind resources vary greatly from one month to the next. The monthly combinations of these resources lead to basically three types of months: solar-biased month, wind-biased month and even month. This, in turn, leads to energy systems in which the energy contributions from photovoltaic and wind generators vary greatly. The monthly and yearly system performances simulations for different types of months show that the system performances vary greatly for varying battery storage capacities and different fractions of photovoltaic and wind energy. As well as the system performance, the optimisation process of such hybrid systems should further consist of the system cost. Therefore, the system performance results are combined with system cost data. The total system cost and the unit cost of the produced electricity (for a 20 year system lifetime) are analysed with strict reference to the yearly system performance. It is shown that an optimum combination of the hybrid photovoltaic–wind energy system provides higher system performance than either of the single systems for the same system cost for every battery storage capacity analysed in the present study. It is also shown that the magnitude of the battery storage capacity has important bearings on the system performance of single photovoltaic and wind systems. The single photovoltaic system performs better than a single wind system for 2 day storage capacity, while the single wind system performs better for 1.25 day storage capacity for the same system cost.     

Development of an integrated gasifier-solid oxide fuel cell test system: A detailed system study

A detailed system study on an integrated gasifier-SOFC test system which is being constructed for combined heat and power (CHP) application is presented. The performance of the system is evaluated using thermodynamic calculations. The system includes a fixed bed gasifier and a 5 kW SOFC CHP system. Two kinds of gas cleaning systems, a combined high and low temperature gas cleaning system and a high temperature gas cleaning system, are considered to connect the gasifier and the SOFC system. A complete model of the gasifier-SOFC system with these two gas cleaning systems is built and evaluated in terms of energy and exergy efficiencies. A sensitivity study is carried out to check system responses to different working parameters. The results of this work show that the electrical efficiencies of the gasifier-SOFC CHP systems with different gas cleaning systems are almost the same whereas the gasifier-SOFC CHP systems with the high temperature gas cleaning system offers higher heat efficiency for both energy and exergy.     

EX21OOe励磁系统故障诊断与预警优化

励磁系统的运行与发电机及电力系统稳定性息息相关。EX2100e系统是目前GE公司燃气轮机的主 流励磁 系统,该系统 、输出信息少,与国产励磁系统差异较大,不利于运行维护人员及时发现 并处理故障。针对这种 ,对该系统的保护、故障报警进行了分析梳理,并实施了故障 化方案, 提升了系统 靠性。     

Multivariable adaptive control for a thermal generator

A digital control system using the optimal control has been developed for a thermal power generator. In order to increase the generator control performance for improving the power system stability, this system supplies the excitation system directly with control signals and provides the governor system with control signals and supplemental control signals for a conventional governor. The system utilizes adaptive control for changes in generator nonlinear characteristics, as well as in power system characteristics. The principles and application of this system are described and results of simulation tests using a 1000 MVA thermal power plant model on a high-reliability AC/DC electric power system simulator are presented. The results verify the performance of this system, as well as the applicability of the system to actual plants     

A new solar and geothermal based integrated ammonia fuel cell system for multigeneration

In this study, a new solar and geothermal based integrated system is developed for multigeneration of electricity, fresh water, hydrogen and cooling. The system also entails a solar integrated ammonia fuel cell subsystem. Furthermore, a reverse osmosis desalination system is used for fresh water production and a proton exchange membrane based hydrogen production system is employed. Moreover, an absorption cooling system is utilized for district cooling via available system waste heat. The system designed is assessed thermodynamically through approaches of energy and exergy analyses. The overall energy efficiency is determined to be 42.3%. Also, the overall exergy efficiency is assessed, and it is found to be 21.3%. The exergy destruction rates in system components are also analysed and the absorption cooling system generator as well as geothermal flash chamber are found to have comparatively higher exergy destruction rates of 2370.2 kW and 643.3 kW, respectively. In addition, the effects of varying system parameters on the system performance are studied through a parametric analyses of the overall system and associated subsystems.     

Analysis and assessment of an advanced hydrogen liquefaction system

In the present work, an advanced hydrogen liquefaction system with catalyst infused heat exchangers is proposed, analyzed and assessed energetically and exergetically. The analysis starts with exergetic considerations on hydrogen liquefaction using different alternatives of pre-cooling including the conversion from normal to parahydrogen. It further explains the fundamentals of a proposed liquefaction process. The goal is then to assess the proposed system, make modifications and improve the system. The present system covers all of these portions of a hydrogen liquefaction system with an ultimate goal of achieving a sustainable and environmentally harmless system. The proposed hydrogen liquefaction system is simulated in the Aspen Plus and the performance of the system is measured through energy and exergy efficiencies. The resulting energy efficiency of the system is calculated to be 15.4%, and the exergy efficiency of the system is found to be 11.5%.