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Effect of 2,5-dimethylfuran addition on ignition delay times of n-heptane at high temperatures

Zhenhua GAO, Erjiang HU, Zhaohua XU, Geyuan YIN, Zuohua HUANG

《能源前沿(英文)》 2019年 第13卷 第3期   页码 464-473 doi: 10.1007/s11708-019-0609-z

摘要: The shock tube autoignition of 2,5-dimethylfuran (DMF)/n-heptane blends (DMF0-100%, by mole fraction) with equivalence ratios of 0.5, 1.0, and 2.0 over the temperature range of 1200–1800 K and pressures of 2.0 atm and 10.0 atm were investigated. A detailed blend chemical kinetic model resulting from the merging of validated kinetic models for the components of the fuel blends was developed. The experimental observations indicate that the ignition delay times nonlinearly increase with an increase in the DMF addition level. Chemical kinetic analysis including radical pool analysis and flux analysis were conducted to explain the DMF addition effects. The kinetic analysis shows that at lower DMF blending levels, the two fuels have negligible impacts on the consumption pathways of each other. As the DMF addition increases to relatively higher levels, the consumption path of n-heptane is significantly changed due to the competition of small radicals, which primarily leads to the nonlinear increase in the ignition delay times of DMF/n-heptane blends.

关键词: ignition delay time     shock tube     kinetic model     2     5-dimethylfuran (DMF)     n-heptane    

Study on electrical ignition and micro-explosion properties of HAN-based monopropellant droplet

Yonggang YU, Ming LI, Yanhuang ZHOU, Xin LU, Yuzhu PAN,

《能源前沿(英文)》 2010年 第4卷 第3期   页码 430-435 doi: 10.1007/s11708-010-0010-4

摘要: In order to study the electrical ignition characteristics of hydroxylammonium nitrate (HAN)-based liquid propellant, an experimental device for the electrical heating ignition of a liquid propellant droplet was designed. By using a high speed camera system, the ignition properties of the LP1846 single droplet were observed at different electrical heating speeds. The results show that when the LP1846 droplet is electrified, it mainly goes through an evaporization process, a periodic expansion and contraction process, a stronger thermal decomposition process, and an ignition and combustion process. The periodic expansion and contraction process accompanies the droplet micro-explosion phenomenon, and the micro-explosion mechanism is formed mainly due to the overheated water component in LP1846. When peak load voltage is from 80 to 140V/s, the ignition delay of the LP1846 droplet is linearly shortened from 0.82 to 0.62s, but the flame is lighter. Based on the above experiments, a simplified model of the electrical heating ignition of the LP1846 single droplet is established.

关键词: liquid propellant     electrical ignition     ignition delay time     transient measurement    

Applicability of high dimensional model representation correlations for ignition delay times of n-heptane

Wang LIU, Jiabo ZHANG, Zhen HUANG, Dong HAN

《能源前沿(英文)》 2019年 第13卷 第2期   页码 367-376 doi: 10.1007/s11708-018-0584-9

摘要: It is difficult to predict the ignition delay times for fuels with the two-stage ignition tendency because of the existence of the nonlinear negative temperature coefficient (NTC) phenomenon at low temperature regimes. In this paper, the random sampling-high dimensional model representation (RS-HDMR) methods were employed to predict the ignition delay times of n-heptane/air mixtures, which exhibits the NTC phenomenon, over a range of initial conditions. A detailed n-heptane chemical mechanism was used to calculate the fuel ignition delay times in the adiabatic constant-pressure system, and two HDMR correlations, the global correlation and the stepwise correlations, were then constructed. Besides, the ignition delay times predicted by both types of correlations were validated against those calculated using the detailed chemical mechanism. The results showed that both correlations had a satisfactory prediction accuracy in general for the ignition delay times of the n-heptane/air mixtures and the stepwise correlations exhibited a better performance than the global correlation in each subdomain. Therefore, it is concluded that HDMR correlations are capable of predicting the ignition delay times for fuels with two-stage ignition behaviors at low-to-intermediate temperature conditions.

关键词: ignition delay     random sampling     high dimensional model representation     n-heptane     fuel kinetics    

A model reference adaptive control based method for actuator delay estimation in real-time testing

Cheng CHEN, James M. RICLES

《结构与土木工程前沿(英文)》 2010年 第4卷 第3期   页码 277-286 doi: 10.1007/s11709-010-0072-8

摘要: Real-time testing provides a viable experimental technique to evaluate the performance of structural systems subjected to dynamic loading. Servo-hydraulic actuators are often utilized to apply calculated displacements from an integration algorithm to the experimental structures in a real-time manner. The compensation of actuator delay is therefore critical to achieve stable and reliable experimental results. The advances in compensation methods based on adaptive control theory enable researchers to accommodate variable actuator delay and achieve good actuator control for real-time tests. However, these adaptive methods all require time duration for actuator delay adaptation. Experiments show that a good actuator delay estimate can help optimize the performance of the adaptive compensation methods. The rate of adaptation also requires that a good actuator delay estimate be acquired especially for the tests where the peak structural response might occur at the beginning of the tests. This paper presents a model reference adaptive control based method to identify the parameter of a simplified discrete model for servo-hydraulic dynamics and the resulting compensation method. Simulations are conducted using both numerical analysis and experimental results to evaluate the effectiveness of the proposed estimation method.

关键词: real-time testing     actuator delay     compensation     adaptive control     MIT rule     discrete transfer function    

Ignition delay of dual fuel engine operating with methanol ignited by pilot diesel

ZOU Hongbo, WANG Lijun, LIU Shenghua, LI Yu

《能源前沿(英文)》 2008年 第2卷 第3期   页码 285-290 doi: 10.1007/s11708-008-0060-z

摘要: An investigation on the ignition delay of a dual fuel engine operating with methanol ignited by pilot diesel was conducted on a TY1100 direct-injection diesel engine equipped with an electronic controlled methanol low-pressure injection system. The experimental results show that the polytropic index of compression process of the dual fuel engine decreases linearly while the ignition delay increases with the increase in methanol mass fraction. Compared with the conventional diesel engine, the ignition delay increment of the dual fuel engine is about 1.5° at a methanol mass fraction of 62%, an engine speed of 1600 r/min, and full engine load. With the elevation of the intake charge temperature from 20°C to 40°C and then to 60°C, the ignition delay of the dual fuel engine decreases and is more obvious at high temperature. Moreover, with the increase in engine speed, the ignition delay of the dual fuel engine by time scale (ms) decreases clearly under all engine operating conditions. However, the ignition delay of the dual fuel engine increases remarkably by advancing the delivery timing of pilot diesel, especially at light engine loads.

基于子空间的离散时滞系统辨识 Article

Qiang LIU,Jia-chen MA

《信息与电子工程前沿(英文)》 2016年 第17卷 第6期   页码 566-575 doi: 10.1631/FITEE.1500358

摘要: 本文研究了具有未知时延的线性随机时滞系统的辨识问题。时滞系统被表达为具有单一时延的时滞差分方程。首先利用状态增广方法将时滞系统转化为一个等价的线性时不变系统,然后采用传统的子空间辨识方法来估计增广系统矩阵。本文提出了一种ACS算法,从而得到时滞系统的状态空间模型。最后,基于ACS算法得到的相似变换,重新得到卡尔曼状态序列。采用最小二乘法,利用卡尔曼状态序列和输入输出数据,得出相同状态空间下的时滞系统矩阵。仿真结果表明了这种算法的有效性。

关键词: 辨识问题;时滞系统;子空间辨识方法;ACS算法;最小二乘法    

考虑输入噪声的混合调制拉格朗日明确时延估计改进算法 Article

Wei XIA,Ju-lei ZHU,Wen-ying JIANG,Ling-feng ZHU

《信息与电子工程前沿(英文)》 2016年 第17卷 第10期   页码 1067-1073 doi: 10.1631/FITEE.1500417

摘要: 概要:混合调制拉格朗日明确时延估计(mixed modulated Lagrange explicit time delay estimation, MMLETDE)算法可对窄带信号或正弦信号提供有效的时延估计

关键词: 时延估计;自适应滤波器;噪声输入;调制拉格朗日法;无偏脉冲响应估计    

An experimental study on ignition of single coal particles at low oxygen concentrations

Wantao YANG, Yang ZHANG, Lilin HU, Junfu LYU, Hai ZHANG

《能源前沿(英文)》 2021年 第15卷 第1期   页码 38-45 doi: 10.1007/s11708-020-0692-1

摘要: An experimental study on the ignition of single coal particles at low oxygen concentrations ( <21%) was conducted using a tube furnace. The surface temperature ( ) and the center temperature ( ) of the coal particles were obtained from the images taken by an infrared camera and thermocouples respectively. The ignition processes were recorded by a high-speed camera at different values and furnace temperatures . Compared with literature experimental data obtained at a high value, the ignition delay time decreases more rapidly as increases at the low region. The responses of and to the variation of are different: decreases while remains nearly constant with increasing at a low value. In addition, is less sensitive to while the ignition temperature is more sensitive to at a low value than in air. Observations of the position of flame front evolution illustrate that the ignition of a coal particle may change from a homogeneous mode to a heterogeneous or combined ignition mode as decreases. At a low value, buoyancy plays a more significant role in sweeping away the released volatiles during the ignition process.

关键词: coal particles     low oxygen concentration     ignition     ignition temperature     ignition modes    

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 432-439 doi: 10.1007/s11708-009-0050-9

摘要: A detailed chemical dynamical mechanism of oxidation of n-heptane was implemented into kiva-3 code to study the ignition mechanism of a high-temperature, high-pressure, three-dimensional-space, transient turbulent, non-homogeneous, mono-component fuel in the engine. By testing the quantity of the heat released by the chemical reaction within the cylinder cell, the elementary reaction showing an obvious increase in the cell temperature was defined as ignition reaction and the corresponding cell as ignition position. The main pathway of the ignition reaction was studied by using the reverse deducing method. The result shows that the ignition in the engine can be divided into low-temperature ignition and high-temperature ignition, both of which follow the same rule in releasing heat, called the impulse heat releasing feature. Low-temperature ignition reaction, whose ignition reaction is c5h9o1-4=ch3cho+c3h5-a, follows the oxidation mechanism, while high-temperature ignition reaction, whose ignition reaction is c2h3o1-2=ch3co, follows the decomposition mechanism. No matter which ignition it is in, the chemical reaction that restrains the ignition reaction from lasting is the deoxidization reaction of alkylperoxy radicals.

关键词: compression-ignition engine     ignition mechanism     elementary reaction     n-heptane    

时滞系统的辨识及NARMA模型的修正

王冬青

《中国工程科学》 2006年 第8卷 第2期   页码 39-43

摘要:

对现有神经网络对非线性时滞系统的时滞辨识方法进行了补充说明和分析,同时指出现有的NARMA模型修正方法对时滞系统的不当之处。以时滞系统神经网络预测控制为例,介绍了NARMA模型的正确修正方法,仿真证明了所提出的修正方法能获得好的控制性能及抗干扰能力。

关键词: 辨识     NARMA模型     神经网络     预测控制    

控制器局域网在错误状态下的报文延时分布研究 Research Papers

Lei-ming ZHANG, Yi-chao SUN, Yong LEI

《信息与电子工程前沿(英文)》 2019年 第20卷 第6期   页码 760-772 doi: 10.1631/FITEE.1700815

摘要: 控制器局域网(CAN)是一种广泛应用于各类工业场景的现场总线协议。为深入理解错误发生时的网络行为并优化网络控制系统设计,需分析CAN网络报文响应时间。本文在考虑错误的基础上,提出一种新颖的CAN网络报文延时分布分析方法,将复杂报文序列分解为典型报文模式和情形。首先开发随机故障模型并定义概率因子计算错误的分布形式,其次基于错误分布分析单个子节点布局下报文的延时分布。然后基于典型报文模式和情形的延时分布,开发多子节点布局下报文延时分布的分析框架。最后搭建实验平台,在不同网络设置下进行多组实验,展示和验证该方法。结果表明该方法计算出的报文延时分布与实际观测值一致。

关键词: 控制器局域网;报文延时;概率分布;错误    

具有任意有限延迟耦合布尔网络的完全同步 Research Articles

Jie LIU, Lulu LI, HabibM. FARDOUN

《信息与电子工程前沿(英文)》 2020年 第21卷 第2期   页码 281-293 doi: 10.1631/FITEE.1900438

摘要: 研究耦合延迟布尔网络完全同步性问题。文中所讨论的耦合延迟布尔网络模型中,状态延迟和输出延迟可能不相等,并且每个布尔网络中的状态延迟也可能不相等。基于矩阵半张量积获得耦合延迟布尔网络达到完全同步的充要条件。提供解决耦合延迟布尔网络完全同步性的有效算法。最后,通过数值算例说明该算法的有效性。

关键词: 布尔网络;同步性;时滞    

状态和控制均具有多时滞的布尔控制网络可控性 Research Article

李一峰1,王兰2

《信息与电子工程前沿(英文)》 2023年 第24卷 第6期   页码 906-915 doi: 10.1631/FITEE.2200618

摘要: 本文研究状态和控制均具有多时滞的布尔控制网络可控性问题。首先,考虑控制具有多时滞的布尔控制网络可控性问题。对于该问题,本文通过定义一个新的矩阵乘积构建系统的可控性矩阵,基于该矩阵,得到一个系统可控的充分必要条件。其次,研究状态具有多时滞的布尔控制网络可控性问题,提出一个状态具有多时滞的布尔控制网络可控的充分必要条件。然后,提出一个状态和控制均具有多时滞的布尔控制网络可控性矩阵,利用该矩阵,提供一个简洁的可控性条件。最后,给出2个例子说明得到的理论结果。

关键词: 布尔控制网络;矩阵半张量积;能控性;时滞    

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

《能源前沿(英文)》 2013年 第7卷 第3期   页码 406-412 doi: 10.1007/s11708-013-0266-6

摘要: To reduce oil consumption during firing-up and partial-load operation, a tiny-oil ignition burner has been recommended. Through reacting-flow experiments performed on a full-scale experimental setup, the influence of different oil flow rates on bituminous coal combustion as well as flow rates without coal feed was analyzed. The ignition burner is identical to that normally used in an 800 MWe utility boiler. Under operating conditions with flow rates of 50, 100, and 150 kg/h, gas temperature distributions were measured in the burner. At the equivalent measuring points at the exits of the first and second combustion chambers, these distributions remained almost unchanged under a constant coal feed rate of 4 t/h. However on the burner centerline, distributions increased slightly with increasing flow rate. Different gas concentrations were measured at the center of the burner exit. For instance, the O concentration at the burner exit varied from 0.01% to 0.31% whereas CO concentrations were more than 10000 ppm. At the same coal feed rate of 4 t/h, burner resistances are 480, 600, and 740 Pa for oil flow rates of 50, 100, and 150 kg/h, respectively.

关键词: ignition     coal     burner     boiler     oil flow rate    

无线多媒体传感器网络中端对端时延资源调配的多层次跨层协议 Regular Papers-Research Articles

Hossein HADADIAN NEJAD YOUSEFI, Yousef SEIFI KAVIAN, Alimorad MAHMOUDI

《信息与电子工程前沿(英文)》 2019年 第20卷 第9期   页码 1266-1276 doi: 10.1631/FITEE.1700855

摘要: 近年来信息和通信技术的讯速发展让无线多媒体传感器网络(WMSNs)面临重要挑战。在传感器网络多媒体应用中,端对端时延和可靠性是关键问题。本文提出一种新的跨层方法,使得网络端对端时延可以确保理想的数据包分组传送率(PDR),此处PDR被用来度量网络可靠性。在提出的多层次跨层(MLCL)协议中,利用远离接收器的跃点数设置每个节点级别。数据包通过以该级别设置的到接收器的最小越点数路径发送。该协议利用网络和多址接入协议(MAC)层之间跨层特性估计最小时延,在该时延下节点能够将数据包传送给接收器。当节点想要发送一个数据包时,MLCL协议会将最小时延与数据包存活时间(TTL)作比较。如果该数据包存活时间大于最小时延,节点通过最小时延路径发送数据包。否则,由于节点不能在TTL内将数据包发送至接收器而丢弃数据包。该数据包的丢弃能够提高网络性能,因为节点能够发送有用数据包以取代无用数据包。结果表明,与当前最先进协议相比,所提协议在端对端时延和可靠性方面表现出优越性能。

关键词: 无线多媒体传感器网络;跨层;存活时间;端对端时延;服务质量    

标题 作者 时间 类型 操作

Effect of 2,5-dimethylfuran addition on ignition delay times of n-heptane at high temperatures

Zhenhua GAO, Erjiang HU, Zhaohua XU, Geyuan YIN, Zuohua HUANG

期刊论文

Study on electrical ignition and micro-explosion properties of HAN-based monopropellant droplet

Yonggang YU, Ming LI, Yanhuang ZHOU, Xin LU, Yuzhu PAN,

期刊论文

Applicability of high dimensional model representation correlations for ignition delay times of n-heptane

Wang LIU, Jiabo ZHANG, Zhen HUANG, Dong HAN

期刊论文

A model reference adaptive control based method for actuator delay estimation in real-time testing

Cheng CHEN, James M. RICLES

期刊论文

Ignition delay of dual fuel engine operating with methanol ignited by pilot diesel

ZOU Hongbo, WANG Lijun, LIU Shenghua, LI Yu

期刊论文

基于子空间的离散时滞系统辨识

Qiang LIU,Jia-chen MA

期刊论文

考虑输入噪声的混合调制拉格朗日明确时延估计改进算法

Wei XIA,Ju-lei ZHU,Wen-ying JIANG,Ling-feng ZHU

期刊论文

An experimental study on ignition of single coal particles at low oxygen concentrations

Wantao YANG, Yang ZHANG, Lilin HU, Junfu LYU, Hai ZHANG

期刊论文

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

期刊论文

时滞系统的辨识及NARMA模型的修正

王冬青

期刊论文

控制器局域网在错误状态下的报文延时分布研究

Lei-ming ZHANG, Yi-chao SUN, Yong LEI

期刊论文

具有任意有限延迟耦合布尔网络的完全同步

Jie LIU, Lulu LI, HabibM. FARDOUN

期刊论文

状态和控制均具有多时滞的布尔控制网络可控性

李一峰1,王兰2

期刊论文

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

期刊论文

无线多媒体传感器网络中端对端时延资源调配的多层次跨层协议

Hossein HADADIAN NEJAD YOUSEFI, Yousef SEIFI KAVIAN, Alimorad MAHMOUDI

期刊论文