Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to ...Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.展开更多
The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper stud...The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper studied the shell-side heat and mass transfer characteristics of vapor-liquid two-phase mixed refrigerants in an SWHE by combining a multi-component model in FLUENT software with a customized multicomponent mass transfer model. Besides, the mathematical model under the sloshing condition was obtained through mathematical derivation, and the corresponding UDF code was loaded into FLUENT as the momentum source term. The results under the sloshing conditions were compared with the relevant parameters under the steady-state condition. The shell-side heat and mass transfer characteristics of the SWHE were investigated by adjusting the component ratio and other working conditions. It was found that the sloshing conditions enhance the heat transfer performance and sometimes have insignificant effects. The sloshing condition is beneficial to reduce the flow resistance. The comprehensive performance of multi-component refrigerants has been improved and the improvement is more significant under sloshing conditions, considering both the heat transfer and pressure drop.These results will provide theoretical support for the research and design of multi-component heat and mass transfer enhancement of LNG SWHE under ocean sloshing conditions.展开更多
The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupansh...The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupanshui raw coal(LPS-R)and Liupanshui demineralized coal(LPS-D)were analyzed by FTIR and solid-state 13C-NMR.The pyrolysis experiments were carried out by TG,and the pyrolysis kinetics was analyzed by three iso-conversional methods.FTIR and 13C-NMR results suggested that the carbon structure of LPS coal was not altered greatly,while demineralization promoted the maturity of coal and the condensation degree of the aromatic ring,making the chemical structure of coal more stable.The oxygen-containing functional groups with low bond energy were reduced,and the ratio of aromatic carbon with high bond energy was increased,decreasing the pyrolysis reactivity.DTG curve-fitting results revealed that the thermal weight loss of LPS coal mainly came from the cleavage of aliphatic covalent bonds.By pyrolysis kinetics analysis of LPS-R and LPS-D,the apparent activation energies were 76±4 to 463±5 kJ/mol and 84±2 to 758±12 kJ/mol,respectively,under different conversion rates.The reactivity of the demineralized coal was inhibited to some extent,as the apparent activation energy of pyrolysis for LPS-D increased by acid treatment.展开更多
Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to inve...Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC.Results show that unlike the low-temperature condition of 873 K,where the peak temperature gradient occurs at the cell center,it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density.Despite the large heat convection capacity,excessive air could not eff ectively eliminate the harmful temperature gradient caused by the large current density.Thus,optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state.Interestingly,the maximum axial temperature gradient could be reduced by about 18%at 973 K and 20%at 1073 K when the air with a 5 K higher temperature is supplied.Additionally,despite the higher electrochemical performance observed,the cell with a counter-fl ow arrange-ment featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability.Overall,this study could provide insightful thermal information for the operating condition selection,structure design,and stability assessment of realistic SOFCs combined with their internal reforming process.展开更多
Nowadays,the utilization rate of electronic products is increasing while showing no obvious sign of reaching a limit.To solve the associated“internal heat generation problem”,scientists have proposed two methods or ...Nowadays,the utilization rate of electronic products is increasing while showing no obvious sign of reaching a limit.To solve the associated“internal heat generation problem”,scientists have proposed two methods or strategies.The first approach consists of replacing the heat exchange medium with a nanofluid.However,the high surface energy of the nanoparticles makes them prone to accumulate along the heat transfer surface.The second method follows a different approach.It tries to modify the surface structure of the electronic components in order to reduce the fluid-dynamic drag and improve the rate of heat exchange.This article reviews these effects considering different types of nanofluid and different shapes,sizes,and arrangements of“biomimetic grooves”.The idea to use these two methods in a combined fashion(to improve heat transfer and reduce flow resistance at the same time)is also developed and discussed critically to a certain extent.展开更多
In the development of 3D conductive frameworks for lithium metal anode(LMA),two models have been proposed:top growth model and bottom-up growth model.However,Li tends to accumulate on the top of these 3D frameworks wi...In the development of 3D conductive frameworks for lithium metal anode(LMA),two models have been proposed:top growth model and bottom-up growth model.However,Li tends to accumulate on the top of these 3D frameworks with homogenous lithiophilicity(top growth)and Li dendrite still forms.To address this issue,some researchers have focused on developing 3D frameworks with gradient lithio-philicity,which realized bottom-up growth of Li.Nevertheless,partial Li nucleation sites on the top of these frameworks were missed.Inspired by the two models talked above,this work firstly proposed a novel intermittent lithiophilic model for lithium deposition.To demonstrate the feasibility of this model,a bimetallic metal-organic frameworks derived ZnMn_(2)O_(4)-MnO nanoparticles were grown on carbon cloth for LMA.It can cycle stably under ultra-high current and areal capacity(10 mA/cm^(2),10 mAh/cm^(2)).The in-situ optical microscopy(OM)was conducted to observe the Li deposition behavior,no dendrite was found during 80 h in ester-based electrolyte while the pure Li only cycled for 2h.What is more,it can also be well-coupled with LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode and solid-state electrolyte,which further prove the advantages of the intermittent model for the development of LMAs with high safety and high energy density.展开更多
The sluggish redox reaction kinetics of lithium polysulfides(LiPSs)are considered the main obstacle to the commercial application of lithium-sulfur(Li-S)batteries.To accelerate the conversion by catalysis and inhibit ...The sluggish redox reaction kinetics of lithium polysulfides(LiPSs)are considered the main obstacle to the commercial application of lithium-sulfur(Li-S)batteries.To accelerate the conversion by catalysis and inhibit the shuttling of soluble LiPSs in Li-S batteries,a solution is proposed in this study.The solution involves fabrication of N,S co-doped carbon coated In_(2)O_(3)/In_(2)S_(3)heterostructure(In_(2)O_(3)-In_(2)S_(3)@NSC)as a multifunctional host material for the cathode.The In_(2)O_(3)-In_(2)S_(3)@NSC composite can reduce the Gibbs free energy for the conversion reactions of LiPSs,which results in superior performance.The synergy between different components in In_(2)O_(3)-In_(2)S_(3)@NSC and the unique 3D structure facilitate ion and electron transport in Li-S batteries.The In_(2)O_(3)-In_(2)S_(3)@NSC/Li 2 S 6 cathode exhibits excellent rate capacity,with a capacity of 599 mAh g−1 at 5.5 C,and good cycle stability,with a capacity of 436 mAh g^(−1)after 1000 cycles at 1 C.Overall,this study proposes a promising solution to improve the energy storage properties of Li-S batteries,which could potentially facilitate the commercialization of Li-S batteries.展开更多
The practicality of conventional solid-liquid phase change materials(PCMs)is adversely restricted by liquid phase leakage,large volume expansion,shape instability,and severe corrosion in high-temperature thermal manag...The practicality of conventional solid-liquid phase change materials(PCMs)is adversely restricted by liquid phase leakage,large volume expansion,shape instability,and severe corrosion in high-temperature thermal management systems.This highlight presents the latest development to resolve these challenges by designing ultrahigh-performance high-temperature Ni-Mn-Ti solid-solid PCMs using martensitic phase transition strategy,offering a new paradigm to develop advanced wide-temperature high-temperature metallic solid-solid phase change thermal storage materials.展开更多
Turbulent environment improves the flotation recovery of fine particles by promoting the particle–bubble collision rate,which directly depends on the particle slip velocity.However,the existing slip velocity models a...Turbulent environment improves the flotation recovery of fine particles by promoting the particle–bubble collision rate,which directly depends on the particle slip velocity.However,the existing slip velocity models are not applicable to fine particles in turbulence.The mechanism of turbulence characteristics and particle properties on the slip velocity of fine particles in turbulence was unclear.In this study,a coupled ANSYS FLUENT and EDEM based on computational fluid dynamics(CFD)and discrete element method(DEM)were used to simulate the slip velocity of fine particles in the approximately homogenous isotropic turbulence,which was excited by the grid.The reliability of the used CFD-DEM simulation method was validated against the slip velocity measured by the particle image velocimetry(PIV)experiments.In particular,the effects of the particle shapes,particle densities,and turbulence intensities on the slip velocity have been investigated with this numerical method.Numerical results show that particle shapes have no significant effect on fine particles between 37 and 225μm.The slip velocity of the spherical particles increases with the turbulence intensity and particle density.Based on the simulated data,a model which has a correlation coefficient of 0.95 is built by using nonlinear fitting.展开更多
As a new type of energy transport medium with high efficiency and high heat transfer performance,nanofluids have shown broad application prospects in the fields of thermodynamics,solar heat collection,microelectronics...As a new type of energy transport medium with high efficiency and high heat transfer performance,nanofluids have shown broad application prospects in the fields of thermodynamics,solar heat collection,microelectronics,thermal energy,and material science.The wide liquid range and environmental properties of ionic liquids have drawn ample attention to their application when used as a working fluid,especially as a base solvent of nanofluids.The ionic liquid-based nanofluids were prepared by a two-step method using 1-ethyl-3-methylimidazole trifluoroacetate ionic liquid as a base solvent and graphene oxide(GO)as a nanofiller.Thermophysical properties study reveals that the thermal conductivity could be enhanced by 3.0%with the addition of 0.05 wt%GO,and the viscosity and the specific heat capacity were also subject to study as a function of testing temperature and concentration of nanofiller.Additionally,the photothermal conversion efficiency of these nanofluids was studied comprehensively under different conditions.The results show that the photothermal conversion efficiency can reach 83%within an irradiation time of 6000 s and the highest temperature of the nanofluids is up to 105.89℃with a maximum photothermal conversion efficiency increase by 29%.展开更多
Porous foam based on renewable materials has attracted extensive attention in green energy conservation and sustainable development.However,there is still a requisite for biomass-based porous foam that could meet the ...Porous foam based on renewable materials has attracted extensive attention in green energy conservation and sustainable development.However,there is still a requisite for biomass-based porous foam that could meet the demand for excellent mechanical and high thermal insulation performances for building insulation.Herein,we demonstrated a facile strategy to prepare a porous foam made from a chitosan matrix reinforced by SiC whisker,which shows good performance in building insulation and mechanical strength.The prepared porous foam has a low density(20.1–54.4 kg m^(-3))and high porosity(>97.0%).The density of the chitosan-SiC porous foam can be controlled by varying the suspension solid and SiC whisker content in the preparation process.Furthermore,the influences of SiC whisker content on the mechanical properties and thermal conductivity of the porous foams were also investigated.When the content of SiC whisker is 30 wt%,the prepared porous foam has the highest compression modulus of about 89.8 kPa and also low thermal conductivity of 0.0354 W m^(-1)K^(-1).Moreover,the prepared porous foam shows excellent water vapor permeability with a vapor resistance factor of 2.94,which is beneficial for moisture transfer in buildings.This work provides a facile way to manufacture biomass-based porous foam,which is potential for energy saving in buildings.展开更多
基金the support of the Opening Fund of State Key Laboratory of Multiphase Flow in Power Engineering(SKLMF-KF-2102)。
文摘Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.
基金funded by the National Natural Science Foundation of China(No.51806236,No.51806239)the Fundamental Research Funds for the Central Universities(No.2015XKMS059)+1 种基金Shaanxi Postdoctoral Fund Project(No.2018BSHEDZZ56)Foundation of Key Laboratory of Thermo-Fluid Science and Engineering(Xi'an Jiaotong University),Ministry of Education(No.KLTFSE2017KF01)。
文摘The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper studied the shell-side heat and mass transfer characteristics of vapor-liquid two-phase mixed refrigerants in an SWHE by combining a multi-component model in FLUENT software with a customized multicomponent mass transfer model. Besides, the mathematical model under the sloshing condition was obtained through mathematical derivation, and the corresponding UDF code was loaded into FLUENT as the momentum source term. The results under the sloshing conditions were compared with the relevant parameters under the steady-state condition. The shell-side heat and mass transfer characteristics of the SWHE were investigated by adjusting the component ratio and other working conditions. It was found that the sloshing conditions enhance the heat transfer performance and sometimes have insignificant effects. The sloshing condition is beneficial to reduce the flow resistance. The comprehensive performance of multi-component refrigerants has been improved and the improvement is more significant under sloshing conditions, considering both the heat transfer and pressure drop.These results will provide theoretical support for the research and design of multi-component heat and mass transfer enhancement of LNG SWHE under ocean sloshing conditions.
基金supported by the National Natural Science Foundation of China (51536002)the Fundamental Research Funds for the Central Universities (2015QNA12)the Open Sharing Fund for the Large-scale Instruments and Equipments of China University of Mining and Technology (CUMT).
文摘The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupanshui raw coal(LPS-R)and Liupanshui demineralized coal(LPS-D)were analyzed by FTIR and solid-state 13C-NMR.The pyrolysis experiments were carried out by TG,and the pyrolysis kinetics was analyzed by three iso-conversional methods.FTIR and 13C-NMR results suggested that the carbon structure of LPS coal was not altered greatly,while demineralization promoted the maturity of coal and the condensation degree of the aromatic ring,making the chemical structure of coal more stable.The oxygen-containing functional groups with low bond energy were reduced,and the ratio of aromatic carbon with high bond energy was increased,decreasing the pyrolysis reactivity.DTG curve-fitting results revealed that the thermal weight loss of LPS coal mainly came from the cleavage of aliphatic covalent bonds.By pyrolysis kinetics analysis of LPS-R and LPS-D,the apparent activation energies were 76±4 to 463±5 kJ/mol and 84±2 to 758±12 kJ/mol,respectively,under different conversion rates.The reactivity of the demineralized coal was inhibited to some extent,as the apparent activation energy of pyrolysis for LPS-D increased by acid treatment.
基金by the Project of Strategic Importance Funding Scheme from The Hong Kong China Polytechnic University(No.P0035168)the National Natural Science Foundation of China(No.51806241).
文摘Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC.Results show that unlike the low-temperature condition of 873 K,where the peak temperature gradient occurs at the cell center,it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density.Despite the large heat convection capacity,excessive air could not eff ectively eliminate the harmful temperature gradient caused by the large current density.Thus,optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state.Interestingly,the maximum axial temperature gradient could be reduced by about 18%at 973 K and 20%at 1073 K when the air with a 5 K higher temperature is supplied.Additionally,despite the higher electrochemical performance observed,the cell with a counter-fl ow arrange-ment featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability.Overall,this study could provide insightful thermal information for the operating condition selection,structure design,and stability assessment of realistic SOFCs combined with their internal reforming process.
基金This work is financially supported by“National Natural Science Foundation of China”(Grant No.51606214).
文摘Nowadays,the utilization rate of electronic products is increasing while showing no obvious sign of reaching a limit.To solve the associated“internal heat generation problem”,scientists have proposed two methods or strategies.The first approach consists of replacing the heat exchange medium with a nanofluid.However,the high surface energy of the nanoparticles makes them prone to accumulate along the heat transfer surface.The second method follows a different approach.It tries to modify the surface structure of the electronic components in order to reduce the fluid-dynamic drag and improve the rate of heat exchange.This article reviews these effects considering different types of nanofluid and different shapes,sizes,and arrangements of“biomimetic grooves”.The idea to use these two methods in a combined fashion(to improve heat transfer and reduce flow resistance at the same time)is also developed and discussed critically to a certain extent.
基金supported by National Natural Science Foundation of China(Nos.21701083,22279112)Fok Ying-Tong Education Foundation of China(No.171064)Natural Science Foundation of Hebei Province(Nos.B2022203018,B2018203297).
文摘In the development of 3D conductive frameworks for lithium metal anode(LMA),two models have been proposed:top growth model and bottom-up growth model.However,Li tends to accumulate on the top of these 3D frameworks with homogenous lithiophilicity(top growth)and Li dendrite still forms.To address this issue,some researchers have focused on developing 3D frameworks with gradient lithio-philicity,which realized bottom-up growth of Li.Nevertheless,partial Li nucleation sites on the top of these frameworks were missed.Inspired by the two models talked above,this work firstly proposed a novel intermittent lithiophilic model for lithium deposition.To demonstrate the feasibility of this model,a bimetallic metal-organic frameworks derived ZnMn_(2)O_(4)-MnO nanoparticles were grown on carbon cloth for LMA.It can cycle stably under ultra-high current and areal capacity(10 mA/cm^(2),10 mAh/cm^(2)).The in-situ optical microscopy(OM)was conducted to observe the Li deposition behavior,no dendrite was found during 80 h in ester-based electrolyte while the pure Li only cycled for 2h.What is more,it can also be well-coupled with LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode and solid-state electrolyte,which further prove the advantages of the intermittent model for the development of LMAs with high safety and high energy density.
基金supported by the National Natural Sci-ence Foundation of China(Nos.51776218 and 52106120)the Natural Science Foundation of Jiangsu Province(No.BK20180083).
文摘The sluggish redox reaction kinetics of lithium polysulfides(LiPSs)are considered the main obstacle to the commercial application of lithium-sulfur(Li-S)batteries.To accelerate the conversion by catalysis and inhibit the shuttling of soluble LiPSs in Li-S batteries,a solution is proposed in this study.The solution involves fabrication of N,S co-doped carbon coated In_(2)O_(3)/In_(2)S_(3)heterostructure(In_(2)O_(3)-In_(2)S_(3)@NSC)as a multifunctional host material for the cathode.The In_(2)O_(3)-In_(2)S_(3)@NSC composite can reduce the Gibbs free energy for the conversion reactions of LiPSs,which results in superior performance.The synergy between different components in In_(2)O_(3)-In_(2)S_(3)@NSC and the unique 3D structure facilitate ion and electron transport in Li-S batteries.The In_(2)O_(3)-In_(2)S_(3)@NSC/Li 2 S 6 cathode exhibits excellent rate capacity,with a capacity of 599 mAh g−1 at 5.5 C,and good cycle stability,with a capacity of 436 mAh g^(−1)after 1000 cycles at 1 C.Overall,this study proposes a promising solution to improve the energy storage properties of Li-S batteries,which could potentially facilitate the commercialization of Li-S batteries.
文摘The practicality of conventional solid-liquid phase change materials(PCMs)is adversely restricted by liquid phase leakage,large volume expansion,shape instability,and severe corrosion in high-temperature thermal management systems.This highlight presents the latest development to resolve these challenges by designing ultrahigh-performance high-temperature Ni-Mn-Ti solid-solid PCMs using martensitic phase transition strategy,offering a new paradigm to develop advanced wide-temperature high-temperature metallic solid-solid phase change thermal storage materials.
基金This work was supported by National Natural Science Foundation of China(grant No.51974310,U21A20325).
文摘Turbulent environment improves the flotation recovery of fine particles by promoting the particle–bubble collision rate,which directly depends on the particle slip velocity.However,the existing slip velocity models are not applicable to fine particles in turbulence.The mechanism of turbulence characteristics and particle properties on the slip velocity of fine particles in turbulence was unclear.In this study,a coupled ANSYS FLUENT and EDEM based on computational fluid dynamics(CFD)and discrete element method(DEM)were used to simulate the slip velocity of fine particles in the approximately homogenous isotropic turbulence,which was excited by the grid.The reliability of the used CFD-DEM simulation method was validated against the slip velocity measured by the particle image velocimetry(PIV)experiments.In particular,the effects of the particle shapes,particle densities,and turbulence intensities on the slip velocity have been investigated with this numerical method.Numerical results show that particle shapes have no significant effect on fine particles between 37 and 225μm.The slip velocity of the spherical particles increases with the turbulence intensity and particle density.Based on the simulated data,a model which has a correlation coefficient of 0.95 is built by using nonlinear fitting.
基金Thanks for financial support from the National Natural Science Foundation of China(No.51906252)the Natural Science Foundation of Jiangsu Province(No.BK20190632).
文摘As a new type of energy transport medium with high efficiency and high heat transfer performance,nanofluids have shown broad application prospects in the fields of thermodynamics,solar heat collection,microelectronics,thermal energy,and material science.The wide liquid range and environmental properties of ionic liquids have drawn ample attention to their application when used as a working fluid,especially as a base solvent of nanofluids.The ionic liquid-based nanofluids were prepared by a two-step method using 1-ethyl-3-methylimidazole trifluoroacetate ionic liquid as a base solvent and graphene oxide(GO)as a nanofiller.Thermophysical properties study reveals that the thermal conductivity could be enhanced by 3.0%with the addition of 0.05 wt%GO,and the viscosity and the specific heat capacity were also subject to study as a function of testing temperature and concentration of nanofiller.Additionally,the photothermal conversion efficiency of these nanofluids was studied comprehensively under different conditions.The results show that the photothermal conversion efficiency can reach 83%within an irradiation time of 6000 s and the highest temperature of the nanofluids is up to 105.89℃with a maximum photothermal conversion efficiency increase by 29%.
基金supported by the National Natural Science Foundation of China(Grant No.52076211)。
文摘Porous foam based on renewable materials has attracted extensive attention in green energy conservation and sustainable development.However,there is still a requisite for biomass-based porous foam that could meet the demand for excellent mechanical and high thermal insulation performances for building insulation.Herein,we demonstrated a facile strategy to prepare a porous foam made from a chitosan matrix reinforced by SiC whisker,which shows good performance in building insulation and mechanical strength.The prepared porous foam has a low density(20.1–54.4 kg m^(-3))and high porosity(>97.0%).The density of the chitosan-SiC porous foam can be controlled by varying the suspension solid and SiC whisker content in the preparation process.Furthermore,the influences of SiC whisker content on the mechanical properties and thermal conductivity of the porous foams were also investigated.When the content of SiC whisker is 30 wt%,the prepared porous foam has the highest compression modulus of about 89.8 kPa and also low thermal conductivity of 0.0354 W m^(-1)K^(-1).Moreover,the prepared porous foam shows excellent water vapor permeability with a vapor resistance factor of 2.94,which is beneficial for moisture transfer in buildings.This work provides a facile way to manufacture biomass-based porous foam,which is potential for energy saving in buildings.
