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1.
Jun Li Nan Gao Guang-yi Cao Heng-yong Tu Ming-ruo Hu Xin-jian Zhu Jian Li 《浙江大学学报(A卷英文版)》2010,11(1):61-70
In this paper, an application of a nonlinear predictive controller based on a self recurrent wavelet network （SRWN） model for a direct internal reforming solid oxide fuel cell （DIR-SOFC） is presented. As operating temperature and fuel utilization are two important parameters, the SOFC is identified using an SRWN with inlet fuel flow rate, inlet air flow rate and current as inputs, and temperature and fuel utilization as outputs. To improve the operating performance of the DIR-SOFC and guarantee proper operating conditions, the nonlinear predictive control is implemented using the off-line trained and on-line modified SRWN model, to manipulate the inlet flow rates to keep the temperature and the fuel utilization at desired levels. Simulation results show satisfactory predictive accuracy of the SRWN model, and demonstrate the excellence of the SRWN-based predictive controller for the DIR-SOFC. 相似文献
2.
本文通过对某炼油厂低压瓦斯气系统分析研究,增加微压自动控制系统,配合装置操作参数的调整,降低瓦斯气含水,将低压瓦斯气引入加热炉作为燃料,使瓦斯气回收率达到85%,节约了燃料油消耗,降低了操作成本,为中小型炼化企业提供了技术改进方向。 相似文献
3.
In view of the present situation of low cavitation performance of deep-sea mining slurry pump, the effect of solid phase on the cavitation performance of deep-sea mining pump is analyzed theoretically. The relationship between gas and liquid phases are established by cavitation nucleon theory and mass energy equation as well as solid phase and liquid phase, and then we explored the relationship between gas phase and solid phase. The results show that the critical bubble radius and solid-phase concentration flow rate during the cavitation can be related to the liquid pressure. Eq. (19) show that the larger the solid particle concentration and the solid phase flow, the earlier the cavitation will occur, and pump anti-cavitation performance will decline. 相似文献
4.
Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external- loop airlift reactor(AELAR)in the bubble flow and developing slug flow pattern. Experiments were performed by using tap-water and silicone oil with the viscosity of 2.0 mm2/s(2cs-SiO)and 5.0 mm2/s(5cs-SiO)as liquid phases. The effects of liquid viscosity and flow pattern on the AELAR performance were investigated. The predictions of the proposed model were in good agreement with the experimental results of the AELAR. In addition, the comparison of the experimental results shows that the proposed model has good accuracy and could be used to predict the gas holdup and liquid velocity of an AELAR operating in bubble and developing flow pattern. 相似文献
5.
Application of neural network in the study of combustion rate of natural gas/diesel dual fuel engine
In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based
on forward neural network was built to study the combustion process of the DFE. The effect of the operating parameters on
combustion rate was also studied by means of this model. The study showed that the predicted results were good agreement with
the experimental data. It was proved that the developed combustion rate model could be used to successfully predict and optimize
the combustion process of dual fuel engine.
Project supported by National Lab. for Automotive Engine and Safety, Tsinghua University, China 相似文献
6.
In this paper, a 60 kW proton exchange membrane fuel cell (PEMFC) generation system is modeled in order to design the system
parameters and investigate the static and dynamic characteristics for control purposes. To achieve an overall system model,
the system is divided into five modules: the PEMFC stack (anode and cathode flows, membrane hydration, and stack voltage and
power), cathode air supply (air compressor, supply manifold, cooler, and humidifier), anode fuel supply (hydrogen valve and
humidifier), cathode exhaust exit (exit manifold and water return), and power conditioning (DC/DC and DC/AC) modules. Using
a combination of empirical and physical modeling techniques, the model is developed to set the operation conditions of current,
temperature, and cathode and anode gas flows and pressures, which have major impacts on system performance. The current model
is based on a 60 kW PEMFC power plant designed for residential applications and takes account of the electrochemical and thermal
aspects of chemical reactions within the stack as well as flows of reactants across the system. The simulation tests show
that the system model can represent the static and dynamic characteristics of a 60 kW PEMFC generation system, which is mathematically
simple for system parameters and control designs. 相似文献
7.
Dependent on automatically generated unstructured grids, a comprehensive computational fluid dynamics(CFD)numerical simulation is performed to analyze the influence of nozzle geometry on the internal flow characteristics of a multi-hole diesel injector with the multi-phase flow model based on Eulerian multi-fluid method.The diesel components in nozzle are considered as two continuous phases, diesel liquid and diesel vapor respectively.Considering that both of them are fully coupled and interpenetrated, sepa... 相似文献
8.
Water management in porous electrodes bears significance due to its strong potential in determining the performance of proton exchange membrane fuel cell.In terms of porous electrodes,internal water distribution and removal process have extensively attracted attention in both experimental and numerical studies.However,the structural difference among the catalyst layer(CL),microporous layer(MPL),and gas diffusion layer(GDL) leads to significant challenges in studying the two-phase flow behavior.Given the different porosities and pore scales of the CL,MPL,and GDL,the model scales in simulating each component are inconsistent.This review emphasizes the numerical simulation related to porous electrodes in the water transport process and evaluates the effectiveness and weakness of the conventional methods used during the investigation.The limitations of existing models include the following:(i) The reconstruction of geometric models is difficult to achieve when using the real characteristics of the components;(ii) the computational domain size is limited due to massive computational loads in three-dimensional(3 D) simulations;(iii) numerical associations among 3 D models are lacking because of the separate studies for each component;(iv) the effects of vapor condensation and heat transfer on the two-phase flow are disregarded;(v) compressive deformation during assembly and vibration in road conditions should be considered in two-phase flow studies given the real operating conditions.Therefore,this review is aimed at critical research gaps which need further investigation.Insightful potential research directions are also suggested for future improvements. 相似文献
9.
邵庆龙 《深圳信息职业技术学院学报》2007,5(2):25-31
质子交换膜燃料电池的水管理是影响其性能的重要因素之一。电池水管理的目的就是要实现尽可能高的膜的水合程度,降低膜的阻抗。为了更好实现以上目标,文中建立了电池水传输模型,基于模型利用工程逼近分析方法,分析了阴阳极湿度、反应气体流量对膜的水含量和阴阳极水分压的影响。仿真结果通过与其他模型相比较,取得了一致的结果,因此也证明了该模型的有效和实用性。基于以上的分析结果为建立简化的膜水含量控制模型和实现水管理的控制目标奠定基础。 相似文献
10.
INTRODUCTIONDuetodwindlingfueloilreservesandthedesireforreducedpollutantemissions,naturalgas,whichisdominantlycomposedofmethane,hasbeennowwidelyusedasanalternativefuelininternalcombustionengines .Aconventionaldieselenginecanbeconvertedwithoutexcessiveincr… 相似文献
11.
On acquiring expertise in medicine 总被引：6，自引：0，他引：6
12.
建立一个主要由熔融碳酸盐燃料电池（MCFC）和斯特林热机组成的新型耦合系统,其中斯特林热机是由在MCFC中产生的高品质废热驱动的。基于电化学和非平衡热力学,考虑各种不可逆损失的影响得到了耦合动力系统的效率和功率输出的解析表达式。研究表明,MCFC的性能可以通过耦合斯特林热机以进一步将废热转化为电输出而大幅度提高。此外,采用数值计算,不仅分析了多个不可逆损失对耦合系统性能的影响,并且还讨论了一些工作条件比如工作温度、输入气体组合以及工作压强对耦合系统性能响。 相似文献
13.
This paper introduces the effects of cell operating temperature, methanol concentration and airflow rate, respectively, on the performance of direct methanol fuel cell （DMFC）. A novel method based on fuzzy neural networks identification technique is proposed to establish the performance model of DMFC. Three dynamic performance models of DMFC under the influences of cell operating temperature, methanol concentration, and airflow rate are identified and established separately. Simulation results show that modeling using fuzzy neural networks identification is satisfactory with high accuracy. It is applicable to DMFC control systems. 相似文献
14.
Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resume, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data. 相似文献
15.
The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical
species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the
model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating
conditions.
Project (No. 50106014) supported by the National Natural Science Foundation of China 相似文献
16.
Based on a three-step kinetic mechanism, a one-dimensional, time dependent, numerical model is presented forthe smoldering propagation in a horizontally packed bed of cellulosic material. The kinetic processes include pyrolysis andoxidation degradation of fuel and oxidation of char. Heat transfer between solid and gas is taken into account, and the diffusioncoefficient varies with the temperature. Radiative heat transfer is included by using the diffusion approximation. The effectsof airflow velocity and oxygen concentration are simulated on the smoldering velocity and the averaged maximum temperatureof smoldering fuel. The results indicate that the spread rate varies linearly with increasing airflow velocity, and the inlet airvelocity has little effect on the maximum temperature. The evolutions of gas species and solid compositions are predicted.The effects of frequency factors (A1, A2 and A3) are analyzed. Simulations show that the smoldering spread rate increaseswith increasing A2 (fuel oxidation), but decreases with A1 (fuel pyrolysis) and A3 (char oxidation). 相似文献
17.
ZITOUNI Bariza BEN MOUSSA Hocine OULMI Kafia 《浙江大学学报(A卷英文版)》2007,8(9):1500-1504
The dimensions and the materials type limit the performance of fuel cell. The increase of the temperature in electrodes and electrolyte of the cell,is due to the over potential of activation (transfer of load),the over potential Ohmic (resistance of polarization),the over potential of reaction (heat released by the chemical reaction) and the over potential of diffusion. In this paper,we studied the thermo-electrical performance of an intermediate temperature solid oxide fuel cell (IT-SOFC) with electrode supported. The aim of this work is to study this increasing temperature of a single cell of an IT-SOFC under the influence of the following parameters: heat sources,functioning temperature and voltages of the cell,geometric configuration and materials type. The equation of energy in one dimension is numerically resolved by using the method of finite volumes. A computing program (FORTRAN) is developed locally for this purpose in order to obtain fields of temperature in every element of the cell. 相似文献
18.
1Introduction Moltencarbonatefuelcell(MCFC)isaclearelec tricitygeneratingtechniquewithhighefficiency,which istobeusedwidely.Withoutcombustion,MCFCcon vertschemicalenergycontainedinfuelandoxidantin toelectricenergyviaelectro chemicalreaction.Per formanceof… 相似文献
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Application of neural network in the study of combustion rate of natural gas/diesel dual fuel engine
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