基于潍柴WP10H改造的单缸机试验平台,深入研究中、高负荷工况充量热力学参数和柴油喷射参数之间的耦合关系及多参数协同获得高热效率的控制方法。结果表明,在平均指示压力(indicated mean effective pressure,IMEP)为1.0 MPa的中负荷工...基于潍柴WP10H改造的单缸机试验平台,深入研究中、高负荷工况充量热力学参数和柴油喷射参数之间的耦合关系及多参数协同获得高热效率的控制方法。结果表明,在平均指示压力(indicated mean effective pressure,IMEP)为1.0 MPa的中负荷工况,提前喷油定时会减少引燃油量的需求量;随着预混天然气当量比增大,柴油喷射定时推迟且喷油定时对引燃油量变化的敏感性降低,指示热效率(indicated thermal efficiency,ITE)和燃烧速率趋于最大值时所需要的最小引燃油量减小;中高负荷工况(IMEP为1.4 MPa)下,增大废气再循环(exhaust gas recirculation,EGR)率需提前喷油定时,增加引燃油量;增压会带来当量比减小从而减缓燃烧速率和提高压缩温度利于快速压燃着火两方面的影响,综合作用取决于混合气自身的热力学氛围。在中负荷工况下,柴油喷射参数的控制需要尽可能地提升燃烧速率以降低燃烧损失,而通过优化当量比调控传热损失与排气损失是提升热效率的关键;在满足粗暴燃烧限值的同时,优化燃烧相位避免过高的排气损失是中高负荷工况提高热效率的关键;随着负荷升高,进气压力与EGR率均增大,最小引燃油量减小,IMEP为1.7 MPa时,ITE可提升至52.1%,最小柴油能量占比为4.7%。展开更多
建立了抑爆球一模八腔仿真分析的有限元模型,基于注塑试验对模型进行验证,采用仿真分析可知,最大锁模力和隔片收缩率对成型质量的影响较大,但两者呈负相关,将其作为优化目标,以5种注塑参数作为影响因素,应用最优拉丁超立方抽样法和不同...建立了抑爆球一模八腔仿真分析的有限元模型,基于注塑试验对模型进行验证,采用仿真分析可知,最大锁模力和隔片收缩率对成型质量的影响较大,但两者呈负相关,将其作为优化目标,以5种注塑参数作为影响因素,应用最优拉丁超立方抽样法和不同阶响应面模型建立两者的数学关系。通过计算复相关系数可知,四阶响应面模型的精度最高,并且将其作为代理模型。利用自适应模拟退火算法(ASA)对代理模型进行自主寻优,得到满足注塑质量要求的最优工艺参数组合,使提高抑爆球的生产效率显著提高。优化后最大锁模力为535.53 k N,与优化前相比,降低了12.15%;优化后隔片收缩率为4.449%,与优化前相比,降低了20.04%,这表明,提出的优化方法效果显著。展开更多
综合能源系统是实现节能减排的有效途径之一,经济性和低碳性对于综合能源系统(integrated energy sys-tem,IES)的运行调度同等重要,设备运行特性对IES运行调度具有重要的影响.本文基于设备运行特性与生命周期理论,构建考虑设备运行特性...综合能源系统是实现节能减排的有效途径之一,经济性和低碳性对于综合能源系统(integrated energy sys-tem,IES)的运行调度同等重要,设备运行特性对IES运行调度具有重要的影响.本文基于设备运行特性与生命周期理论,构建考虑设备运行特性的输入能源(柴油、天然气、系统内新能源机组、大电网输入电能)生命周期碳排放数据库.基于碳排放数据库,考虑碳交易机制,建立IES经济低碳模型.该模型在考虑设备运行约束与系统能量转换特点基础上,以系统总成本最小为优化目标对系统运行进行优化,该优化目标中包含了运行成本与碳交易成本.通过算例分析与低碳模型、经济模型相比较,发现IES经济低碳模型能兼顾系统经济性和低碳性,能在以较低经济成本运行的同时,产生较少的碳排放.基于IES经济低碳模型,通过不同场景的对比分析,分析不同碳交易价格下的IES运行特性,得出碳交易价格变化与IES经济低碳运行的相关性,为碳交易价格的制定提供一定建议.考虑微型燃气轮机与柴油发电机运行特性,分析两类设备不同最大运行效率变化下IES经济低碳运行特点,从设备层面与系统层面基于运行效率变化对IES经济低碳运行特点进行分析,得出了最大运行效率变化对IES经济低碳运行的影响规律,为IES规划和运行优化提供一定参考和建议.展开更多
An experimental study was performed to compare the effects of high-and low-pressure exhaust gas recirculation loops(HP and LP EGR loops)on thermal efficiency and emissions of a diesel engine.Tests were conducted on a ...An experimental study was performed to compare the effects of high-and low-pressure exhaust gas recirculation loops(HP and LP EGR loops)on thermal efficiency and emissions of a diesel engine.Tests were conducted on a 12-L six-cylinder turbocharged diesel engine under various operating conditions.We found that at a low speed of 1100 r/min,1 MPa BMEP,the LP EGR loop could achieve higher brake thermal efficiency and lower emissions than the HP EGR.This is because the lower enthalpy available at the turbine inlet of the HP EGR loop increased the fuel/oxygen equivalence ratio.For the HP EGR,the gross indicated thermal efficiency was reduced by 1%,but pumping losses were only reduced by 0.5%,compared to the LP EGR loop.At a higher speed of 1600 r/min,1 MPa BMEP,the HP EGR loop attained a higher brake thermal efficiency and lower emissions because of the relatively sufficient flow through the turbocharger.For the HP EGR loop,the gross indicated thermal efficiency was only reduced by 0.5%and pumping losses were reduced by 1.5%,compared to the LP EGR loop.Lower fuel consumption and a longer ignition delay made the distribution of fuel/oxygen equivalence ratio more homogeneous,leading to lower emissions.Our data also showed that at the high speed of 1600 r/min,0.55 MPa BMEP,the brake thermal efficiency of the HP EGR loop first increased,then decreased as the EGR rate increased.Therefore,under all conditions,a reasonable match of both EGR loops could achieve a good balance between fuel consumption and emissions of NOx and soot.展开更多
文摘建立了抑爆球一模八腔仿真分析的有限元模型,基于注塑试验对模型进行验证,采用仿真分析可知,最大锁模力和隔片收缩率对成型质量的影响较大,但两者呈负相关,将其作为优化目标,以5种注塑参数作为影响因素,应用最优拉丁超立方抽样法和不同阶响应面模型建立两者的数学关系。通过计算复相关系数可知,四阶响应面模型的精度最高,并且将其作为代理模型。利用自适应模拟退火算法(ASA)对代理模型进行自主寻优,得到满足注塑质量要求的最优工艺参数组合,使提高抑爆球的生产效率显著提高。优化后最大锁模力为535.53 k N,与优化前相比,降低了12.15%;优化后隔片收缩率为4.449%,与优化前相比,降低了20.04%,这表明,提出的优化方法效果显著。
文摘综合能源系统是实现节能减排的有效途径之一,经济性和低碳性对于综合能源系统(integrated energy sys-tem,IES)的运行调度同等重要,设备运行特性对IES运行调度具有重要的影响.本文基于设备运行特性与生命周期理论,构建考虑设备运行特性的输入能源(柴油、天然气、系统内新能源机组、大电网输入电能)生命周期碳排放数据库.基于碳排放数据库,考虑碳交易机制,建立IES经济低碳模型.该模型在考虑设备运行约束与系统能量转换特点基础上,以系统总成本最小为优化目标对系统运行进行优化,该优化目标中包含了运行成本与碳交易成本.通过算例分析与低碳模型、经济模型相比较,发现IES经济低碳模型能兼顾系统经济性和低碳性,能在以较低经济成本运行的同时,产生较少的碳排放.基于IES经济低碳模型,通过不同场景的对比分析,分析不同碳交易价格下的IES运行特性,得出碳交易价格变化与IES经济低碳运行的相关性,为碳交易价格的制定提供一定建议.考虑微型燃气轮机与柴油发电机运行特性,分析两类设备不同最大运行效率变化下IES经济低碳运行特点,从设备层面与系统层面基于运行效率变化对IES经济低碳运行特点进行分析,得出了最大运行效率变化对IES经济低碳运行的影响规律,为IES规划和运行优化提供一定参考和建议.
基金supported by the National High Technology Research and Development Program of China("863" Program)(Grant No.2012AA111714)
文摘An experimental study was performed to compare the effects of high-and low-pressure exhaust gas recirculation loops(HP and LP EGR loops)on thermal efficiency and emissions of a diesel engine.Tests were conducted on a 12-L six-cylinder turbocharged diesel engine under various operating conditions.We found that at a low speed of 1100 r/min,1 MPa BMEP,the LP EGR loop could achieve higher brake thermal efficiency and lower emissions than the HP EGR.This is because the lower enthalpy available at the turbine inlet of the HP EGR loop increased the fuel/oxygen equivalence ratio.For the HP EGR,the gross indicated thermal efficiency was reduced by 1%,but pumping losses were only reduced by 0.5%,compared to the LP EGR loop.At a higher speed of 1600 r/min,1 MPa BMEP,the HP EGR loop attained a higher brake thermal efficiency and lower emissions because of the relatively sufficient flow through the turbocharger.For the HP EGR loop,the gross indicated thermal efficiency was only reduced by 0.5%and pumping losses were reduced by 1.5%,compared to the LP EGR loop.Lower fuel consumption and a longer ignition delay made the distribution of fuel/oxygen equivalence ratio more homogeneous,leading to lower emissions.Our data also showed that at the high speed of 1600 r/min,0.55 MPa BMEP,the brake thermal efficiency of the HP EGR loop first increased,then decreased as the EGR rate increased.Therefore,under all conditions,a reasonable match of both EGR loops could achieve a good balance between fuel consumption and emissions of NOx and soot.
