Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR pr...Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR products,liquid oxygenates(Oxys)are especially attractive due to their high energy density,high safety and transportability that could be adapted to the existing infrastructure and transportation system.However,efficiently generating these highly reduced oxygen-containing products by ECR remains challenging due to the complexity of coupled proton and electron transfer processes.In recent years,in-depth studies of reaction mechanisms have advanced the design of catalysts and the regulation of reaction systems for ECR to produce Oxys,Here,by focusing on the production of typical Oxys,such as methanol,acetic acid,ethanol,acetone,n-propanol,and isopropanol,we outline various reaction paths and key intermediates for the electrochemical conversion of CO_(2)into these target products.We also summarize the current research status and recent advances in catalysts based on their elemental composition,and consider recent studies on the change of catalyst geometry and electronic structure,as well as the optimization of reaction systems to increase ECR performance.Finally,we analyze the challenges in the field of ECR to Oxys and provide an outlook on future directions for high-efficiency catalyst prediction and design,as well as the development of advanced reaction systems.展开更多
The thermal protection of rocket engines is a crucial aspect of rocket engine design.In this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber ...The thermal protection of rocket engines is a crucial aspect of rocket engine design.In this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling model.The accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust chamber.Additionally,key parameters related to heat transfer performance were calculated.The results demonstrate that the model is sufficiently accurate to be used as a preliminary design tool.The temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer analysis.In addition,the performance of composite cooling is observed to be superior to regenerative cooling.Increasing the gas film flow rate results in higher cooling efficiency and a lower gas-side wall temperature.Furthermore,the position at which the gas film is introduced greatly impacts the cooling performance.The optimal introduction position for the gas film is determined when the film is introduced from a single row of holes.This optimal introduction position results in a more uniform wall temperature distribution and reduces the peak temperature.Lastly,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall temperature.These results provide a basis for the design of gas film/regenerative composite cooling systems.展开更多
The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic beh...The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic behavior of liquid oxygen （LOX） feeding pipe system in a large scale launch vehicle is performed,with the effect of fluid-structure interaction （FSI） taken into consideration.The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling.Numerical tests on pipes between the tank and the pump are solved by the finite volume method.Results show that restrictions weaken the interaction between axial and lateral vibrations.The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis,and thus highlight the usefulness of the proposed model.This study would provide a reference to the pipe test,as well as facilitate further studies on oscillation suppression.展开更多
For capturing and recycling of CO_(2)in the internal combustion engine,Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techn...For capturing and recycling of CO_(2)in the internal combustion engine,Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle.However,due to the water spray nozzle need to be installed on the cylinder,which increases the cylinder head design difficulty and makes the combustion conditions become more complicated.In this paper,a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines.The proposed new method uses liquid oxygen to solidify part of cooled CO_(2)from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system.The other part of CO_(2)is sent to inlet system and mixed with oxygen,which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable.Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program.The effects of exhaust gas recirculation(EGR)rate are analyzed on the temperatures,the pressures and the instantaneous heat release rates when the EGR rate is more than 8%.The possibility of enclosing intake and exhaust system for engine is verified.The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO_(2)capture experiment is carried out.The experimental results show that when the EGR rate is 36%for the optimum EGR rate.When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min,respectively,21.50-701.30 g dry ice is obtained.This research proposes a new design method which can capture CO_(2)for vehicular internal combustion engine.展开更多
Hierarchical BiOBr microspheres with oxygen vacancies, which can be used for the dyes removal, have been synthesized successfully in the presence of different kinds of ionic liquids. It was revealed that BiOBr prepare...Hierarchical BiOBr microspheres with oxygen vacancies, which can be used for the dyes removal, have been synthesized successfully in the presence of different kinds of ionic liquids. It was revealed that BiOBr prepared by the ionic liquids with short chain length exhibited higher photocatalytic activity in the degradation of methyl orange （MO） under visible light. The experimental results showed that the phenomenon of the photocatalytic degradation of MO can be explained by the photoluminescence spectra.展开更多
Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid ...Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.展开更多
A few factors affecting plasma oxidation desulfurization of ethyl- thioether were investigated.Under the typical conditions,the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and...A few factors affecting plasma oxidation desulfurization of ethyl- thioether were investigated.Under the typical conditions,the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and 79% respectively.展开更多
Methane chemistry is one of the“Holy Grails of catalysis”.It is highly desirable but challenge to transform methane into value-added chemicals,because of its high C-H bonding energy(435 kJ/mol),lack ofπbonding or u...Methane chemistry is one of the“Holy Grails of catalysis”.It is highly desirable but challenge to transform methane into value-added chemicals,because of its high C-H bonding energy(435 kJ/mol),lack ofπbonding or unpaired electrons.Currently,commercial methane conversion is usually carried out in harsh conditions with enormous energy input.Photocatalytic partial oxidation of methane to liquid oxygenates(PPOMO)is a future-oriented technology towards realizing high efficiency and high selectivity under mild conditions.The selection of oxidant is crucial to the PPOMO performance.Hence,attentions are paid to the research progress of PPOMO with various oxidants(O_(2),H_(2)O,H_(2)O_(2)and other oxidants).Moreover,the activation of the selected oxidants is also highly emphasized.Meanwhile,we summarized the methane activation mechanisms focusing on the C-H bond that was broken mainly by·OH radical,O-specie or photogenerated hole(h+).Finally,the challenges and prospects in this subject are briefly discussed.展开更多
基金financial supports from the National Natural Science Foundation of China(52201237)the Talent Introduction Project of Chinese Academy of Sciences(E344011)+4 种基金the Shenzhen High Level Talent Team Project(KQTD2022110109364705)the Joint Research Project of China Merchants Group and SIAT(E2Z1521)the Cross Institute Joint Research Youth Team Project of SIAT(E25427)National Natural Science Foundation of China(52402136)the China Postdoctoral Science Foundation(E325281005)。
文摘Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR products,liquid oxygenates(Oxys)are especially attractive due to their high energy density,high safety and transportability that could be adapted to the existing infrastructure and transportation system.However,efficiently generating these highly reduced oxygen-containing products by ECR remains challenging due to the complexity of coupled proton and electron transfer processes.In recent years,in-depth studies of reaction mechanisms have advanced the design of catalysts and the regulation of reaction systems for ECR to produce Oxys,Here,by focusing on the production of typical Oxys,such as methanol,acetic acid,ethanol,acetone,n-propanol,and isopropanol,we outline various reaction paths and key intermediates for the electrochemical conversion of CO_(2)into these target products.We also summarize the current research status and recent advances in catalysts based on their elemental composition,and consider recent studies on the change of catalyst geometry and electronic structure,as well as the optimization of reaction systems to increase ECR performance.Finally,we analyze the challenges in the field of ECR to Oxys and provide an outlook on future directions for high-efficiency catalyst prediction and design,as well as the development of advanced reaction systems.
基金supported by the National Science Fund Project(No.2019-JCJQ-ZQ-019)the Innovative Research Group Project of National Natural Science Foundation of China(No.T2221002).
文摘The thermal protection of rocket engines is a crucial aspect of rocket engine design.In this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling model.The accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust chamber.Additionally,key parameters related to heat transfer performance were calculated.The results demonstrate that the model is sufficiently accurate to be used as a preliminary design tool.The temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer analysis.In addition,the performance of composite cooling is observed to be superior to regenerative cooling.Increasing the gas film flow rate results in higher cooling efficiency and a lower gas-side wall temperature.Furthermore,the position at which the gas film is introduced greatly impacts the cooling performance.The optimal introduction position for the gas film is determined when the film is introduced from a single row of holes.This optimal introduction position results in a more uniform wall temperature distribution and reduces the peak temperature.Lastly,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall temperature.These results provide a basis for the design of gas film/regenerative composite cooling systems.
文摘The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic behavior of liquid oxygen （LOX） feeding pipe system in a large scale launch vehicle is performed,with the effect of fluid-structure interaction （FSI） taken into consideration.The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling.Numerical tests on pipes between the tank and the pump are solved by the finite volume method.Results show that restrictions weaken the interaction between axial and lateral vibrations.The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis,and thus highlight the usefulness of the proposed model.This study would provide a reference to the pipe test,as well as facilitate further studies on oscillation suppression.
基金Supported by National Natural Science Foundation of China(Grant No.51176082)Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions of China(Grant No.CIT&TCD20140311)Beijing Municipal Natural Science Foundation of China(Grant No.SQKZ201510016004)
文摘For capturing and recycling of CO_(2)in the internal combustion engine,Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle.However,due to the water spray nozzle need to be installed on the cylinder,which increases the cylinder head design difficulty and makes the combustion conditions become more complicated.In this paper,a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines.The proposed new method uses liquid oxygen to solidify part of cooled CO_(2)from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system.The other part of CO_(2)is sent to inlet system and mixed with oxygen,which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable.Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program.The effects of exhaust gas recirculation(EGR)rate are analyzed on the temperatures,the pressures and the instantaneous heat release rates when the EGR rate is more than 8%.The possibility of enclosing intake and exhaust system for engine is verified.The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO_(2)capture experiment is carried out.The experimental results show that when the EGR rate is 36%for the optimum EGR rate.When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min,respectively,21.50-701.30 g dry ice is obtained.This research proposes a new design method which can capture CO_(2)for vehicular internal combustion engine.
基金supported by funding from The Chinese Ministry of Education for the Scientific Key Project (No. 109094)
文摘Hierarchical BiOBr microspheres with oxygen vacancies, which can be used for the dyes removal, have been synthesized successfully in the presence of different kinds of ionic liquids. It was revealed that BiOBr prepared by the ionic liquids with short chain length exhibited higher photocatalytic activity in the degradation of methyl orange （MO） under visible light. The experimental results showed that the phenomenon of the photocatalytic degradation of MO can be explained by the photoluminescence spectra.
基金supported by the Natural Science Foundation of China(No.51706190)the State Scholarship Fund of China Scholarship Council。
文摘Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.
基金The project was supported by National Natural Science Foundation of China
文摘A few factors affecting plasma oxidation desulfurization of ethyl- thioether were investigated.Under the typical conditions,the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and 79% respectively.
基金the National Key R&D Program of China(No.2021YFA1500800)National Natural Science Foundation of China(No.22072106).
文摘Methane chemistry is one of the“Holy Grails of catalysis”.It is highly desirable but challenge to transform methane into value-added chemicals,because of its high C-H bonding energy(435 kJ/mol),lack ofπbonding or unpaired electrons.Currently,commercial methane conversion is usually carried out in harsh conditions with enormous energy input.Photocatalytic partial oxidation of methane to liquid oxygenates(PPOMO)is a future-oriented technology towards realizing high efficiency and high selectivity under mild conditions.The selection of oxidant is crucial to the PPOMO performance.Hence,attentions are paid to the research progress of PPOMO with various oxidants(O_(2),H_(2)O,H_(2)O_(2)and other oxidants).Moreover,the activation of the selected oxidants is also highly emphasized.Meanwhile,we summarized the methane activation mechanisms focusing on the C-H bond that was broken mainly by·OH radical,O-specie or photogenerated hole(h+).Finally,the challenges and prospects in this subject are briefly discussed.
