Research on the Explosion Temperature Response of Fuel Air Explosive Measured by Colorimetric Pyrometer

An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature responses of primary initiation FAE and secondary initiation FAE in real time. And the characteristics of their temperature history curves were compared and analyzed. The results show that the primary initiation FAE has higher explosion temperature and longer duration compared to the secondary initiation FAE.

A new equivalent method to obtain the stoichiometric fuel-air cloud from the inhomogeneous cloud based on FLACS-dispersion

The fuel-air cloud resulting from an accidental discharge event is normally irregular in shape and varying in concentration. Performance of dispersion simulations using the computational fluid dynamics （CFD）-based tool FLACS can get an uneven and irregular cloud. For the performance of gas explosion study with FLACS, the equivalent stoichiometric fuel-air cloud concept is widely applied to get a representative distribution of explosion loads. The Q9 cloud model that is employed in FLACS is an equivalent fuel-air cloud representation, in which the laminar burning velocity with first order SL and volume expansion ratio are taken into consideration. However, during an explosion in congested areas, the main part of the combustion involves turbulent flame propagation. Hence, to give a more reasonable equivalent fuel-air size, the turbulent burning velocity must be taken into consideration. The paper presents a new equivalent cloud method using the turbulent burning velocity, which is described as a function of SL, deduced from the TNO multi- energy method.

Transient Air-Fuel Ratio Control in a CNG Engine Using Fuzzy Neural Networks

The fuzzy neural networks has been used as means of precisely controlling the air-fuel ratio of a lean-burn compressed natural gas (CNG) engine. A control algorithm, without based on engine model, has been (utilized) to construct a feedforward/feedback control scheme to regulate the air-fuel ratio. Using fuzzy neural networks, a fuzzy neural hybrid controller is obtained based on PI controller. The new controller, which can adjust parameters online, has been tested in transient air-fuel ratio control of a CNG engine.

Adaptive Air-Fuel Ratio Control with MLP Network

This paper presents an application of adaptive neural network model-based predictive control (MPC) to the air-fuel ratio of an engine simulation. A multi-layer perceptron (MLP) neural network is trained using two on-line training algorithms: a back propagation algorithm and a recursive least squares (RLS) algorithm. It is used to model parameter uncertainties in the nonlinear dynamics of internal combustion (IC) engines. Based on the adaptive model, an MPC strategy for controlling air-fuel ratio is realized, and its control performance compared with that of a traditional PI controller. A reduced Hessian method, a newly developed sequential quadratic programming (SQP) method for solving nonlinear programming (NLP) problems, is implemented to speed up nonlinear optimization in the MPC. Keywords Air-fuel ratio control - IC engine - adaptive neural networks - nonlinear programming - model predictive control Shi-Wei Wang PhD student, Liverpool John Moores University; MSc in Control Systems, University of Sheffield, 2003; BEng in Automatic Technology, Jilin University, 2000; Current research interests automotive engine control, model predictive control, sliding mode control, neural networks.Ding-Li Yu obtained B.Eng from Harbin Civil Engineering College, Harbin, China in 1981, M.Sc from Jilin University of Technology, Changchun, China in 1986 and PhD from Coventry University, U.K. in 1995, all in control engineering. He is currently a Reader in Process Control at Liverpool John Moores University, U.K. His current research interests are in process control, engine control, fault detection and adaptive neural nets. He is a member of SAFEPROCESS TC in IFAC and an associate editor of the IJMIC and the IJISS.

Adaptive inverse control of air supply flow for proton exchange membrane fuel cell systems

To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control （AIC） strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell （PEMFC） system in this paper. The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network （RFNN） is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances. Compared with the PI controller, numerical simulations are performed to validate the effectiveness and advantages of the proposed AIC strategy.

Study on a Closed-Loop Air-Fuel Control System of Gasoline Engines by Simulation

In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model of closed loop control system including the engine, air fuel mixing and transportation, oxygen sensor and controller, etc., is developed. Various factors that influence the A/F control are studied by simulation. The simulation results show that the reference voltage of oxygen sensor will influence the mean value of A/F ratio, the controller parameters will influence the amplitude of A/F fluctuation, and the operating conditions of the engine determine the frequency of A/F fluctuations, the amplitude of A/F fluctuation can be reduced to within demanded values by logical selection of the signal acquisition method and controller parameters. Higher A/F fluctuation frequency under high speed and load can be reduced through software delay in the controller. The A/F closed loop control system based on the simulation results, accompanied with a rare earth element TWC, gives a better efficiency of conversion against harmful emissions.

Air flow control based on optimal oxygen excess ratio in fuel cells for vehicles

Air flow control is one of the most important control methods for maintaining the stability and reliability of a fuel cell system, which can avoid oxygen starvation or oxygen saturation. The oxygen excess ratio （OER） is often used to indicate the air flow condition. Based on a fuel cell system model for vehicles, OER performance was analyzed for different stack currents and temperatures in this paper, and the results show that the optimal OER was affected weakly by the stack temperature. In order to ensure the system working in optimal OER, a control scheme that includes an optimal OER regulator and a fuzzy control was proposed. According to the stack current, a reference value of air flow rate was obtained with the optimal OER regulator and then the air compressor motor voltage was controlled with the fuzzy controller to adjust the air flow rate provided by the air compressor. Simulation results show that the control method has good dynamic and static characteristics.

Assessment of Health Effects Related to the Use of Biomass Fuel and Indoor Air Pollution in Kapkokwon Sub-Location, Bomet Country, Kenya

Biomass Fuel (BMF) refers to burned plant or animal material;wood, charcoal, dung and crop residues which account for more than half of domestic energy in most developing countries and for as much as 95% in low income countries. It is estimated that about 3 billion people in the world rely on biomass fuel for cooking, heating and lighting. The biomass fuel chain includes gathering, transportation, processing and combustion. These processes are predominantly managed by women where they work as gatherers, processors, carriers or transporters and also as end-users or cooks. Thus, they suffer health hazards at all stages of the biomass fuel chain. The main objective was to assess health effects related to the use of Biomass fuel and indoor air pollution in Kapkokwon Sub-location, Kericho County, Kenya from March to May, 2013. The study area was Kapkokwon sub location, Bomet County, Kenya. The study population was 202 households. Primary females of the household were the target group as they managed the biomass chain. A quantitative descriptive cross-sectional study design was adopted to assess the health effects associated to the use of biomass fuel and indoor air pollution. The research revealed that women suffer different type of physical ailments due to the biomass fuel chain. Physical exhaustion (86%), neck aches (78%), headaches (34%), knee aches (30%) and back aches (16%) were reported as the principal health effects associated with the third stage of the biomass fuel chain. Irritation of the mucus membrane of the eyes, nose and throat (100%), coughing (100%), burns (42%), shortness of breath (38%) and exacerbation of asthma (2%) were identified as principal health effects associated with the fourth stage of the biomass fuel chain (cooking). As a result of the detrimental impact of indoor air pollution (IAP) on health and mortality, many governments, non-governmental organization and international organizations should develop strategies aimed at reducing indoor air pollution. The strategies to include subsidization of cleaner fuel technologies, development, promotion and subsidization of improved cooking stoves, use of solar thermal cookers and solar hot water heaters, processing biomass fuel to make them cleaner, modifying user behavior and improved household design.

Air Pollution, Global Warming and Difficulties to Replace Fossil Fuel with Renewable Energy

Since the Industrial Revolution, greenhouse gas (GHG) emissions have greatly increased with the increased use of fossil fuels, leading to air pollution and global warming. We present the researches on air pollution and the use of fossil fuels in north China, the economic zone of Changsha-Zhuzhou-Xiangtan and the economic zone of the Pearl River Delta region. Researches indicate that the use of fossil fuels has been the main source of air pollution in the three regions. We present researches on global mean surface temperature (GMST) with the rise of carbon dioxide concentration (CDC) and global fossil fuel consumption (GFFC);researches indicate that the rise in CDC can account for 91% of the rise in GMST, and GFFC can account for 90% of the rise in GMST. We analyse the factors that bring about air pollution and temperature rise, they are the use of fossil fuels and deforestation. It is critically important to replace fossil fuels with clean energy, but renewable energy has also disadvantages. The world faces difficulties in solving air pollution and global warming, so governments of the world should cooperate to solve the technologies of clean energy, and preserve the forests and the natural environment.

Effect of Center High Explosive in Dispersion of Fuel

The dispersion of the fuel due to the center high explosive, including several different physical stages, is analyzed by means of experimental results observed with a high speed motion analysis system, and the effect of center high explosive charge is suggested. The process of the fuel dispersion process can be divided into three main stages, acceleration, deceleration and turbulence. Within a certain scope, the radius of the final fuel cloud dispersed is independent of the center explosive charge mass in an FAE (fuel air explosive) device, while only dependent both on the duration of acceleration stage and on that of the deceleration. In these two stages, the dispersion of the fuel dust mainly occurs along the radial direction. There is a close relation between the fuel dispersion process and the center explosive charge mass. To describe the motion of fuel for different stages of dispersion, different mechanical models should be applied.

Experimental Study on Single Ignition Characteristics of Mixed Solid and Liquid Fuel

In order to probe into the single ignition characteristics of mixed solid and liquid fuel, optical and electrical experinments on unconfined volume dispersion and single ignition of few dosage of ternary fuel mixture are successfully done. Experimental results show that cloud detonation is distinguished from explosion of trinitrotoluene charge. The single ignition process of mixed fuel containing aluminum powder（Al）, propylene oxide （PO） and explosive （TNT） can be divided into four stages, the overpressure within its explosion field first increases, then decays with increase of distance. Explosion effects can be enhanced with adding proper trinitrotoluene into fuel mixture, the optimized ratio is m （Al） ： m （PO）： m （TNT） - 55：35： 10. The overpressure of binary mixed fuel containing Al and TNT decays like trinitrotoluene charge with increase of distance, but its value is higher than the trinitrotoluene charge＇s in the same mass at longer distance. The continual action time of plus overpressure during cloud detonation reaches magnitude of 10 ms and is about 100 times longer than the trinitrotoluene charge＇ s.

Using KELEA (Kinetic Energy Limiting Electrostatic Attraction) to Improve the Efficiency of Fuel Combustion

There are many reports of devices and fuel additives being able to enhance the performance of automobiles and other forms of transportation that rely upon the combustion of gasoline or diesel fuels. The claims extend from increased mileage and power to significant reductions in toxic exhaust emissions of carbon monoxide and unburnt hydrocarbons. Progress towards more widespread applications of means of improving fuel efficiency has been impeded by the lack of a coherent explanation of the mechanism of action. Fuel combustion allows for the conversion of much of the available chemical energy in volatile hydrocarbons to mechanical energy, which moves the pistons within an engine. It is proposed that the amount of chemical energy in hydrocarbons can be increased by the absorption of an environmental force termed KELEA (kinetic energy limiting electrostatic attraction). In addition to providing greater mechanical energy with relatively less heat output, the combustion of KELEA activated fuels proceeds further with less toxic emissions of carbon monoxide and unburnt hydrocarbons from incomplete combustion. KELEA activation of fuels should become standard practice in the transportation industry, with potential additional benefits in slowing the rate of global warming.

Hydrogen Engine and Numerical Temperature-Entropy Chart for Hydrogen/Air Cycle Analysis

Fast depletion of fossil fuels with its resources already passed its mid depletion region and the pollution levels already reached unsafe levels which make it utmost necessity to search for alternative fuels to meet sustainable energy demand with minimum environmental impact. Among alternative fuels, hydrogen is considered as the near future, long term renewable, sustainable and non-polluting fuel. In the present paper, hydrogen fueled internal combustion engine fundamentals highlighted and presented relating to hydrogen combustion properties. A Mat lab programmed hydrogen temperature-entropy-energy chart is developed and presented for fresh charge and products of combustion at different excess air factors per mole combustion gases. The chart, then, used to represent a SI hydrogen-fueled fuel/air cycle analysis, which proved to be valuable design tool for engine sizing and for prediction of engine performance. Predictions carried out using the hydrogen F/A cycle analysis at different λ show low brake specific fuel consumption and low volume specific power compared with conventional SI engine.

Influence of fuel quality on vehicular NOx emissions

The quality of gasoline and diesel fuel affects pollutant emissions from vehicles. By applying the COMPLEX model, developed by the US EPA and industry to relate fuel composition to vehicle emissions, this paper estimates the influence of improvements in gasoline quality to lower vehicular NOx emissions. A case study is performed for Guangzhou City that has NOx concentrations significantly above the national ambient air quality standards (NAAQS). The paper discusses the potential for reducing NOx in Guangzhou by improving the quality of gasoline.

Materials Research Advances towards High-Capacity Battery/Fuel Cell Devices(Invited paper)

The world has entered an era featured with fast transportations,instant communications,and prompt technological revolutions,the further advancement of which all relies fundamentally,yet,on the development of cost-effective energy resources allowing for durable and high-rate energy supply.Current battery and fuel cell systems are challenged by a few issues characterized either by insufficient energy capacity or by operation instability and,thus,are not ideal for such highly-demanded applications as electrical vehicles and portable electronic devices.In this mini-review,we present,from materials perspectives,a few selected important breakthroughs in energy resources employed in these applications.Prospectives are then given to look towards future research activities for seeking viable materials solutions for addressing the capacity,durability,and cost shortcomings associated with current battery/fuel cell devices.

Experimental Study on Characteristics of Cathode Fan Systems of Proton Exchange Membrane Fuel Cells

对自制的阴极开放式自增湿型质子交换膜燃料电池阴极风扇系统不同工作模式下电池的空气流量分布及温度分布开展了实验研究。采用testo435多功能测量仪测量不同工作模式下电池阴极的空气流速；采用FLUKETi25红外温度成像仪测量不同操作模式下电池的表面温度分布。实验结果表明：阴极风扇系统不同的工作模式（“吸”和“吹”）会造成空气流量分布及温度分布不同。风扇工作在“吸．”模式下，燃料电池的表面工作温度分布和空气流量分布更均匀，性能更好；电池表面工作温度分布与流过电池阴极的空气流量具有一致性。该研究对于阴极开放式燃料电池性能研究及寻求电池系统效率、性能、温湿度等整体最优具有一定的指导和参考价值。

The Levels of Toxic Air Pollutants in Kitchens with Traditional Stoves in Rural Sierra Leone

Wood and charcoal fuels, widely used in Sierra Leone for cooking, may impact indoor air quality. Until now, there is presently lack of data to quantify the extent of impact. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs), suspended particulate matter (SPM) and carbon monoxide (CO) were measured in kitchens with wood and charcoal stoves during cooking in rural areas. PAH contents of PM2.5 and PM2.5 - 10 fractions were analyzed using HPLC/FLD and SPM and CO were monitored in realtime. Mean ± SD concentrations of PM2.5 related ∑11PAHs, PM and CO were 2127 ± 1173 ng/m3, 1686 ± 973 μg/m3 and 28 ± 9 ppm for wood stoves;and 158 ± 106 ng/m3, 315 ± 205 μg/m3 and 42 ± 21 ppm for charcoal stoves, respectively. PAHs were largely associated with PM2.5 than PM2.5 - 10. Maximum 1-hr time averaged ± SD CO concentration for kitchens with wood and charcoal stoves were 44 ± 21 ppm and 77 ± 49 ppm, respectively. Generally, concentrations of PAHs, PM and CO were higher than the WHO recommended guidelines which raise concern with regards to health risks. Given the existing evidence of reduced emissions of PAHs, PM and CO from cleaner fuels, a transition from cooking with wood and charcoal to cleaner fuels would provide an improvement in indoor air quality, a requirement for good health.

燃料电池空压机气磁悬浮系统的协同控制研究

针对燃料电池空压机目前存在的驱动和支承问题,提出一种箔片动压轴承和动力磁轴承一体化的气磁悬浮型空压机。基于空压机的结构组成,建立空压机磁悬浮支承力、气悬浮支承力以及空压机转子动力学数学模型;基于燃料电池空压机转子系统动力学模型的状态空间方程,设计抗干扰强的协同控制器,并对它进行了转速、驱动转矩、转子悬浮位移以及电磁调节力等关键物理量的仿真分析。结果表明:协同控制在响应、抗干扰以及鲁棒性方面的控制优于PID控制。基于协同控制和PID控制建立了控制实验平台,并对空压机转子的气磁悬浮进行分析,进一步验证了协同控制具有优良的控制效果和良好的控制性能。

PEMFC空气系统流量和压力协同控制策略设计

为提高质子交换膜燃料电池(PEMFC)空气系统的动态响应性能,避免局部缺气而导致其输出性能降低等问题的出现,针对空气系统存在流量和压力耦合的问题,分别采用PID、前馈解耦控制和模型预测控制(MPC)对空气系统进行控制,通过仿真和台架测试,验证控制算法的有效性。结果表明,两种控制算法相比较PID均具有较好的控制效果,空气流量和空气压力均能快速跟随设定值,PEMFC发动机的输出性能平稳。

油气场站火灾爆炸风险的神经支持决策树识别与预测

为了有效防控油气场站火灾爆炸事故,从影响因素之间因果关系的角度出发,提出利用神经支持决策树(Neural-Backed Decision Tree,NBDT)算法构建油气火灾爆炸可解释预测模型。该方法利用词频逆向文件频率(Term Frequency-Inverse Document Frequency,TF-IDF)算法从风险描述信息中提取出关键词并计算权重,整合得到64个风险二级因素,构建了油气场站的火灾爆炸数据集;采用神经支持决策树算法构建分类模型,对油气场站火灾爆炸事故进行预测和可解释分析,可以基于数据可视化地分析油气火灾爆炸事故的风险与诱因。结果表明,NBDT模型预测准确率为0.976,AUC为0.913,明显优于其他模型;模型可视化结果分别从单因素和多因素角度分析,确立7种二级风险主控因素和6种二级风险组合主控因素。13种风险主控因素的确立,可以为既有油气场站火灾爆炸预测和防控机制提供理论支撑。