The operating temperature of a solid oxide fuel cell (SOFC) stack is a very important parameter to be controlled, which impacts the performance of the SOFC due to thermal cycling. In this paper, an adaptive fuzzy cont...The operating temperature of a solid oxide fuel cell (SOFC) stack is a very important parameter to be controlled, which impacts the performance of the SOFC due to thermal cycling. In this paper, an adaptive fuzzy control method based on an affine nonlinear temperature model is developed to control the temperature of the SOFC within a specified range. Fuzzy logic systems are used to approximate nonlinear functions in the SOFC system and an adaptive technique is employed to construct the controller. Compared with the traditional fuzzy and proportion-integral-derivative (PID) control, the simulation results show that the designed adaptive fuzzy control method performed much better. So it is feasible to build an adaptive fuzzy controller for temperature control of the SOFC.展开更多
Effects of butanol isomers on characteristics of combustion and emission were studied on PFI SI engine. Experiments were operated under the condition of 3 and 5 bar brake mean effective pressure (BMEP) engine loads an...Effects of butanol isomers on characteristics of combustion and emission were studied on PFI SI engine. Experiments were operated under the condition of 3 and 5 bar brake mean effective pressure (BMEP) engine loads and different equivalence ratios (φ=0.83-1.25) with engine speed of 1200 r/min using blends made of 70 vol.% gasoline and 30 vol.% butanol isomers (N30, S30, I30 and T30). The results indicated that compared with gasoline, all butanol isomer blends have higher cylinder pressure. N30 has the highest and most advanced peak pressure, and T30 shows a higher brake specific fuel consumption (BSFC) and lower brake thermal efficiency (BTE). N30 presents a lower UHC emissions and I30 has slightly higher CO emissions than other blends. For unregulated emissions, compared with gasoline, butanol isomer blends have higher acetaldehyde, and N30 produces a higher emission of 1,3-butadiene than other blends. A reduction in benzene, toluene, ethylbenzene and xylene (BTEX) has been found with butanol isomer blends.展开更多
The aim of the present study is to develop the biomass furnace combustor which can effectively employ four unused biomasses, i.e., wood bark, wood branch, bamboo, and grass as a fuel. Emphasis is placed on the combust...The aim of the present study is to develop the biomass furnace combustor which can effectively employ four unused biomasses, i.e., wood bark, wood branch, bamboo, and grass as a fuel. Emphasis is placed on the combustion gas components and combustion gas temperature in the combustor. It is found from the study that： （1） Four unused biomasses can take plate self combustion and the stable combustion yield; （2） Different combustion temperature distribution appears in combustor and is affected by each biomass; （3） The concentrations of nitrogen oxide and sulfur oxides are lower than the discharge standard value; （4） Higher thermal efficiency yields for bark, bamboo and grass.展开更多
Black carbon （BC） aerosol, accounting for a minor fraction of atmospheric aerosols, is attracting increased attentio1 due to its impact on air quality, human health, and climate change. Focusing on BC emission reduc...Black carbon （BC） aerosol, accounting for a minor fraction of atmospheric aerosols, is attracting increased attentio1 due to its impact on air quality, human health, and climate change. Focusing on BC emission reduction, this paper give1 a brief introduction to the sources and global distribution of BC. Along with the decrease of BC emissions from sue1 actions as the reduction of global greenhouse gases （GHGs） and regulating local air quality, it also highlights othet BC reduction approaches such as control and improvement of combustion conditions, the elimination of open biomas burning, and the sequestration of BC by biomass pyrolysis. Finally, it is stressed that at this moment there is no enougt reason to push BC reduction into any climate change related negotiations, although BC has been included in some o so-called win-win reduction targets for the quick response to both climate and non-climate appeals.展开更多
Studied the changes of heat physical parameters, gas concentration of O_2, CO,CH_4 and H_2, and temperature through full scale wood fire experiments in a tunnel and simulationby FLUNET, a kind of computational fluid d...Studied the changes of heat physical parameters, gas concentration of O_2, CO,CH_4 and H_2, and temperature through full scale wood fire experiments in a tunnel and simulationby FLUNET, a kind of computational fluid dynamics software.The results showthat the wood fire experiment and simulation are both oxygen-enriched combustions,which show that the simulation results coincide with the experiment.The results also provethat it is difficult for oxygen-enriched combustion to cause secondary disasters.Somesuggestions were put forward to prevent the occurrence of secondary disasters effectively.展开更多
The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often rema...The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often remains in the recirculation zone,achieving stability of flame.This study investigates, by means of experiments,the variations of the aerodynamics as the fluid is injected into a combustion chamber through a double concentric burner with a bluff-body.The observation and measurement of the aerodynamics in our experiment are conducted under a cold flow.The controlled parameters in our experiment are:variations in the blockage ratio of the center bluff body,the cone angle of the bluff body,and the velocity ratio(U_s/U_p)of the secondary jet and primary jet;the injection of helium bubbles into the primary and secondary jets to observe the recirculation zone behind the bluff body;using Tufts for observing the characteristics of corner recirculation zone in a combustion chamber,measuring the average velocity of each point within the aerodynamics by the 5-hole pitot tube;measuring the distribution of static pressure of the combustion chamber walls with a static pressure tap.展开更多
Modeling aluminum(Al)dust detonation is difficult due to uncertainties in the product species and fractions.Recent experiments indicate both gaseous and solid alumina may appear in the detonation product,but only the ...Modeling aluminum(Al)dust detonation is difficult due to uncertainties in the product species and fractions.Recent experiments indicate both gaseous and solid alumina may appear in the detonation product,but only the gaseous one was considered before.To resolve this drawback,we study the effects of different product phases on the detonation parameters with the hybrid combustion model proposed recently.Numerical results demonstrate that the assumption of gaseous product induces high velocity and pressure,while the assumption of solid product induces low velocity and pressure.To clarify how close-to-experiment results have been obtained with one phase assumption,we revisit previous studies and analyze the models.The inconsistency between the product phase and heat release is found,and then one model with variable heat release dependent on the product phase is proposed.Then simulations with both the gaseous and solid products are carried out,and results reveal the necessity of establishing a relationship between the heat release and reaction products.展开更多
基金国家自然科学基金项目 ( 4 9975 0 2 640 3 180 0 1) +1 种基金Research Grant Council of HongKong (PolyU 5 0 61/99E)The Hong Kong Polytechnic Uni versity (G YW 5 8)共同资助
文摘The operating temperature of a solid oxide fuel cell (SOFC) stack is a very important parameter to be controlled, which impacts the performance of the SOFC due to thermal cycling. In this paper, an adaptive fuzzy control method based on an affine nonlinear temperature model is developed to control the temperature of the SOFC within a specified range. Fuzzy logic systems are used to approximate nonlinear functions in the SOFC system and an adaptive technique is employed to construct the controller. Compared with the traditional fuzzy and proportion-integral-derivative (PID) control, the simulation results show that the designed adaptive fuzzy control method performed much better. So it is feasible to build an adaptive fuzzy controller for temperature control of the SOFC.
基金Projects(51776016,51606006) supported by the National Natural Science Foundation of ChinaProjects(3172025,3182030) supported by Beijing Natural Science Foundation,China+4 种基金Project(2017YFB0103401) supported by National Key Research and Development ProgramProject(NELMS2017A10) funded by the National Engineering Laboratory for Mobile Source Emission Control Technology,ChinaProject(2018RC017) supported by the Talents Foundation of Beijing Jiaotong University,ChinaProject(DE-EE0006864) supported by the Department of EnergyProject(201507090044) supported by China Scholarship Council
文摘Effects of butanol isomers on characteristics of combustion and emission were studied on PFI SI engine. Experiments were operated under the condition of 3 and 5 bar brake mean effective pressure (BMEP) engine loads and different equivalence ratios (φ=0.83-1.25) with engine speed of 1200 r/min using blends made of 70 vol.% gasoline and 30 vol.% butanol isomers (N30, S30, I30 and T30). The results indicated that compared with gasoline, all butanol isomer blends have higher cylinder pressure. N30 has the highest and most advanced peak pressure, and T30 shows a higher brake specific fuel consumption (BSFC) and lower brake thermal efficiency (BTE). N30 presents a lower UHC emissions and I30 has slightly higher CO emissions than other blends. For unregulated emissions, compared with gasoline, butanol isomer blends have higher acetaldehyde, and N30 produces a higher emission of 1,3-butadiene than other blends. A reduction in benzene, toluene, ethylbenzene and xylene (BTEX) has been found with butanol isomer blends.
文摘The aim of the present study is to develop the biomass furnace combustor which can effectively employ four unused biomasses, i.e., wood bark, wood branch, bamboo, and grass as a fuel. Emphasis is placed on the combustion gas components and combustion gas temperature in the combustor. It is found from the study that： （1） Four unused biomasses can take plate self combustion and the stable combustion yield; （2） Different combustion temperature distribution appears in combustor and is affected by each biomass; （3） The concentrations of nitrogen oxide and sulfur oxides are lower than the discharge standard value; （4） Higher thermal efficiency yields for bark, bamboo and grass.
基金co-supported by China 973 project of MOST(2011CB403401)China Postdoctoral Science Foundation(20080440463,200902157)
文摘Black carbon （BC） aerosol, accounting for a minor fraction of atmospheric aerosols, is attracting increased attentio1 due to its impact on air quality, human health, and climate change. Focusing on BC emission reduction, this paper give1 a brief introduction to the sources and global distribution of BC. Along with the decrease of BC emissions from sue1 actions as the reduction of global greenhouse gases （GHGs） and regulating local air quality, it also highlights othet BC reduction approaches such as control and improvement of combustion conditions, the elimination of open biomas burning, and the sequestration of BC by biomass pyrolysis. Finally, it is stressed that at this moment there is no enougt reason to push BC reduction into any climate change related negotiations, although BC has been included in some o so-called win-win reduction targets for the quick response to both climate and non-climate appeals.
基金Supported by the National"Eleventh Five-Year"Key Scientific and Technological Support Program Project(2007BAK22B04)2008 Independent Task(SKLCRSM08B12)
文摘Studied the changes of heat physical parameters, gas concentration of O_2, CO,CH_4 and H_2, and temperature through full scale wood fire experiments in a tunnel and simulationby FLUNET, a kind of computational fluid dynamics software.The results showthat the wood fire experiment and simulation are both oxygen-enriched combustions,which show that the simulation results coincide with the experiment.The results also provethat it is difficult for oxygen-enriched combustion to cause secondary disasters.Somesuggestions were put forward to prevent the occurrence of secondary disasters effectively.
文摘The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often remains in the recirculation zone,achieving stability of flame.This study investigates, by means of experiments,the variations of the aerodynamics as the fluid is injected into a combustion chamber through a double concentric burner with a bluff-body.The observation and measurement of the aerodynamics in our experiment are conducted under a cold flow.The controlled parameters in our experiment are:variations in the blockage ratio of the center bluff body,the cone angle of the bluff body,and the velocity ratio(U_s/U_p)of the secondary jet and primary jet;the injection of helium bubbles into the primary and secondary jets to observe the recirculation zone behind the bluff body;using Tufts for observing the characteristics of corner recirculation zone in a combustion chamber,measuring the average velocity of each point within the aerodynamics by the 5-hole pitot tube;measuring the distribution of static pressure of the combustion chamber walls with a static pressure tap.
基金supported by the National Natural Science Foundation ofChina(Grant No.90916028)
文摘Modeling aluminum(Al)dust detonation is difficult due to uncertainties in the product species and fractions.Recent experiments indicate both gaseous and solid alumina may appear in the detonation product,but only the gaseous one was considered before.To resolve this drawback,we study the effects of different product phases on the detonation parameters with the hybrid combustion model proposed recently.Numerical results demonstrate that the assumption of gaseous product induces high velocity and pressure,while the assumption of solid product induces low velocity and pressure.To clarify how close-to-experiment results have been obtained with one phase assumption,we revisit previous studies and analyze the models.The inconsistency between the product phase and heat release is found,and then one model with variable heat release dependent on the product phase is proposed.Then simulations with both the gaseous and solid products are carried out,and results reveal the necessity of establishing a relationship between the heat release and reaction products.
