Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existin...Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existing catalyst is limited due to the poor activity and stability,which hinders its industrialization.Herein,we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles(NPs)as bifunctional catalysts(NPs@Zn-MFI)for CO_(2)-ODP.Characterization results reveal that the Zn2+species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt,Rh,or Rh Pt are highly dispersed in the zeolite crystals.The isolated Zn2+cations are very effective for activating the propane and the small NPs are favorable for activating the CO_(2),which synergistically promote the selective transformation of propane and CO_(2)to propylene and CO.As a result,the optimal 0.25%Rh0.50%Pt@Zn-MFI catalyst shows the best propylene yield,satisfactory CO_(2)conversion,and long-term stability.Moreover,considering the tunable synergetic effects between the isolated cations and NPs,the developed approach offers a general guideline to design more efficient CO_(2)-ODP catalysts,which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn4+cations for Zn2+cations in the MFI zeolite matrix.展开更多
This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat...This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.展开更多
This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat...This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.展开更多
The present work relates to a numerical investigation of double diffusive mixed convection around a horizontal annulus with a finned inner cylinder.The solutal and thermal buoyancy forces are sustained by maintaining ...The present work relates to a numerical investigation of double diffusive mixed convection around a horizontal annulus with a finned inner cylinder.The solutal and thermal buoyancy forces are sustained by maintaining the inner and outer cylinders at uniform temperatures and concentrations.Buoyancy effects are also considered,with the Boussinesq approximation.The forced convection effect is induced by the outer cylinder rotating with an angular velocity(ω)in an anti-clockwise direction.The studies are made for various combinations of dimensionless numbers;buoyancy ratio number(N),Lewis number(Le),Richardson number(Ri)and Grashof number(Gr).The isotherms,isoconcentrations and streamlines as well as both average and local Nusselt and Sherwood numbers were studied.A finite volume scheme is adopted to solve the transport equations for continuity,momentum,energy and mass transfer.The results indicate that the use of fins on the inner cylinder with outer cylinder rotation,significantly improves the heat and mass transfer in the annulus.展开更多
This paper numerically investigates the effect of the location of a horizontal fin on the melting of a phase change material(PCM)inside a rectangular enclosure heated by multiple discrete pulsed protruding heat source...This paper numerically investigates the effect of the location of a horizontal fin on the melting of a phase change material(PCM)inside a rectangular enclosure heated by multiple discrete pulsed protruding heat sources.The fin and the phase change material filling the enclosure store the thermal energy extracted from the heat sources,in sensible and latent forms.The heat sources are assumed to simulate electronic components undergoing a superheating technical issue.By extracting heat from the electronics,the PCM plays the role of a heat sink.To analyze the thermal behavior and predict the cooling performance of the proposed cooling system,we derive a nonlinear mathematical model based on mass,momentum and energy conservation laws.Several numerical investigations are conducted to quantify the influence of the fin position on the thermal behavior and the cooling performance of the heat sink.Predictions include the transient maximum temperature occurring inside the heat sources and the liquid volume.A comparison between our numerical results and experimental data selected from the literature shows a good agreement.The main conclusion is that the presence of the fin leads to a slight increase in the melting time.展开更多
The heat storage performance of latent heat storage systems is not good due to the poor thermal conductivity of phase change materials.In this paper,a new type of pointer-shaped fins combining rectangular and triangul...The heat storage performance of latent heat storage systems is not good due to the poor thermal conductivity of phase change materials.In this paper,a new type of pointer-shaped fins combining rectangular and triangular fins has been employed to numerically simulate the melting process in the heat storage tank,and the fin geometry parameter effects on heat storage performance have been studied.The results indicate that compared with the bare tube and the rectangular finned tank,the melting time of the phase change material in the pointer-shaped finned tank is reduced by 64.2%and 15.1%,respectively.The closer the tip of the triangular fin is to the hot wall,the better the heat transfer efficiency.The optimal height of the triangular fin is about 8 mm.Increasing the number of fins from 4 to 6 and from 6 to 8 reduces the melting time by 16.0%and 16.7%respectively.However,increasing the number of fins from 8 to 10 only reduces the melting time by 8.4%.When the fin dimensionless length is increased from 0.3 to 0.5 and from 0.5 to 0.7,the melting time is shortened by 17.5%and 13.0%.But the melting time is only reduced by 2.9%when the dimensionless fin length is increased from 0.7 to 0.9.For optimising the design of the thermal storage system,the results can provide a reference value.展开更多
Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which ca...Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which can provide different grades of thermal energy with two heat transfer fluids(oil and water),is designed to improve thermal efficiency.In this FPTR-IT,an inner tube and straight fins are employed to respectively lessen heat loss at upper and lower parts of the absorber.Based on the design,a numerical model is developed to investigate its performance.Comparisons with other PTRs indicate that the FPTR-IT can combine the advantages of PTR with inner tube and finned PTR and obtain the best performance.Moreover,performance evaluation under broad ranges of direct normal irradiances(300–1000 W/m^(2)),flow rates(50–250 L/min)and inlet temperatures(400–600 K)of oil as well as flow rates(3.6–10 L/min)and inlet temperatures(298.15–318.15 K)of water is investigated.Compared with conventional PTR,heat loss is reduced by 20.7%–63.2%and total efficiency is improved by 0.03%–4.27%.Furthermore,the proportions of heat gains for water and oil are located in 8.3%–73.9%and-12.0%–64.3%,while their temperature gains are located in 11.6–37.9 K and-1.2–19.6 K,respectively.Thus,the proposed FPTR-IT may have a promising application prospect in remote arid areas or islands to provide different grades of heat for electricity and freshwater production.展开更多
In this article,a new evaporative condenser with an annular elliptic firmed tube heat exchanger that includes a round inner tube and elliptic outer finned tube was designed and analyzed.The refrigerant flows between t...In this article,a new evaporative condenser with an annular elliptic firmed tube heat exchanger that includes a round inner tube and elliptic outer finned tube was designed and analyzed.The refrigerant flows between the round inner tube and the elliptic outer tube,and it simultaneously exchanges heat with the cooling water in the inner tube,the spray water,and the cooling air flowing past the outer tube.Using field measurement for the traditional round finned tube evaporative condenser in the Futong Metro Station of Line 14 in Beijing,China,the theoretical heat transfer performance of the annular elliptic finned tube evaporative condenser was analyzed and simulated.Compared with a round finned tube heat exchanger,the heat exchange capacity of the annular elliptic finned tube increased by 2.34%to 9.28%;the total heat transfer coefficient increased by 47.42%,and the power consumption of the fan in the air-conditioning system with an annular elliptic finned tube heat exchanger decreased by 11.18%to 14.65%.Therefore,the energy-saving performance and the heat transfer performance of the new annular elliptic finned tube heat exchanger were enhanced compared to the round finned tube heat exchanger.展开更多
The Tbx family is first known through the study of their functions in the body and limbs,and its members Tbx4 and Tbx5 genes are important factors in determining the characteristics of the appendages.Pampus argenteus ...The Tbx family is first known through the study of their functions in the body and limbs,and its members Tbx4 and Tbx5 genes are important factors in determining the characteristics of the appendages.Pampus argenteus is one of the important economical marine fishes widely distributed in offshore areas.Therefore,it is necessary to study the role of Tbx family genes in the deletion of pelvic fin in P.argenteus.In this study,we cloned Tbx4 and Tbx5 cDNA sequence of P.argenteus(GenBank:MH709128 and MH712458).The Western blot and real time PCR were used to detect the expressions of Tbx4 and Tbx5 in different developmental stages and tissues of P.argenteus.In addition,whole-mount in-situ hybridization was used to study the localization of Tbx4 and Tbx5 genes in different developmental stages of P.argenteus.Results show that the translation of Tbx4 mRNA was inhibited during the critical period of pelvic fin development.Among different tissues,Tbx4 protein levels were the lowest in the abdominal epithelium,and even lower than that in the pectoral fin,suggesting that the protein expression was also inhibited in the abdominal epithelium of adult P.argenteus.Therefore,the results indicated that upstream genes regulation led to the key stage-specific and low expression of Tbx4 during pelvic fin development and in the abdominal epithelium.展开更多
The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, a...The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.展开更多
An investigation of the decoupled thermal–hydraulic analysis of a separated heat pipe spent fuel pool passive cooling system(SFS)is essential for practical engineering applications.Based on the principles of thermal ...An investigation of the decoupled thermal–hydraulic analysis of a separated heat pipe spent fuel pool passive cooling system(SFS)is essential for practical engineering applications.Based on the principles of thermal and mass balance,this study decoupled the heat transfer processes in the SFS.In accordance with the decoupling conditions,we modeled the spent fuel pool of the CAP1400 pressurized water reactor in Weihai and used computational fluid dynamics to explore the heat dissipation capacity of the SFS under different air temperatures and wind speeds.The results show that the air-cooled separated heat pipe radiator achieved optimal performance at an air temperature of 10℃ or wind speed of 8 m/s.Fitted equations for the equivalent thermal conductivity of the separated heat pipes with the wind speed and air temperature we obtained according to the thermal resistance network model.This study is instructive for the actual operation of an SFS.展开更多
The performance of an integrated thermal management system signi?cantly in?uences the stability of special-purpose vehicles;thus,enhancing the heat transfer of the radiator is of great signi?cance.Common research meth...The performance of an integrated thermal management system signi?cantly in?uences the stability of special-purpose vehicles;thus,enhancing the heat transfer of the radiator is of great signi?cance.Common research methods for radiators include?uid mechanics numerical simulations and experimental measurements,both of which are time-consuming and expensive.Applying the surrogate model to the analysis of the?ow and heat transfer in louvered?ns can effectively reduce the computational cost and obtain more data.A simpli?ed louvered-?n heat transfer unit was established,and computational?uid dynamics(CFD)simulations were conducted to obtain the?ow and heat transfer characteristics of the geometric structure.A three-factor and six-level orthogonal design was established with three structural parameters:angleθ,length a,and pitch L_p of the louvered?ns.The results of the orthogonal design were subjected to a range analysis,and the effects of the three parametersθ,a,and L_p on the j,f,and JF factors were obtained.Accordingly,a proxy model of the heat transfer performance for louvered?ns was established based onthe arti?cial neural network algorithm,and the model was trained with the data obtained by the orthogonal design.Finally,the?n structure with the largest JF factor was realized.Compared with the original model,the optimizedmodel improved the heat transfer factor j by 2.87%,decreased the friction factor f by 30.4%,and increased the comprehensive factor JF by 15.7%.展开更多
A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current article.The periodic variation in the fin base temperature is taken into account a...A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current article.The periodic variation in the fin base temperature is taken into account along with the temperature sensitive thermal conductivity and convective heat transfer coefficients.The modeled problem,which is resolved into a non-linear partial differential equation(PDE),is made dimensionless and solved by employing the finite difference method(FDM).The results are displayed through graphs and discussed.The effects of amplitude,frequency of oscillation,wet nature,Peclet number,and other relevant quantities on the distribution of temperature through the fin length and with the dimensionless time are investigated.It is deciphered that the periodic heat transfer gives rise to the wavy nature of the fin thermal profile against time.The analysis is beneficial in the design of fin structures for applications like solar collectors,space/airborne applications,and refrigeration industries.展开更多
The variations of single event transient(SET)pulse width of high-LET heavy ion irradiation in 16-nm-thick bulk silicon fin field-effect transistor(Fin FET)inverter chains with different driven strengths are measured a...The variations of single event transient(SET)pulse width of high-LET heavy ion irradiation in 16-nm-thick bulk silicon fin field-effect transistor(Fin FET)inverter chains with different driven strengths are measured at different temperatures.Three-dimensional(3D)technology computer-aided design simulations are carried out to study the SET pulse width and saturation current varying with temperature.Experimental and simulation results indicate that the increase in temperature will enhance the parasitic bipolar effect of bulk Fin FET technology,resulting in the increase of SET pulse width.On the other hand,the increase of inverter driven strength will change the layout topology,which has a complex influence on the SET temperature effects of Fin FET inverter chains.The experimental and simulation results show that the device with the strongest driven strength has the least dependence on temperature.展开更多
An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously obs...An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.展开更多
基金supported by the National Natural Science Foundation of China(21902097,21636006 and 21761132025)the China Postdoctoral Science Foundation(2019M653861XB)+1 种基金the Natural Science Foundation of Shaanxi Province(2020JQ-409)the Fundamental Research Funds for the Central Universities(GK201901001 and GK202003035)。
文摘Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existing catalyst is limited due to the poor activity and stability,which hinders its industrialization.Herein,we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles(NPs)as bifunctional catalysts(NPs@Zn-MFI)for CO_(2)-ODP.Characterization results reveal that the Zn2+species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt,Rh,or Rh Pt are highly dispersed in the zeolite crystals.The isolated Zn2+cations are very effective for activating the propane and the small NPs are favorable for activating the CO_(2),which synergistically promote the selective transformation of propane and CO_(2)to propylene and CO.As a result,the optimal 0.25%Rh0.50%Pt@Zn-MFI catalyst shows the best propylene yield,satisfactory CO_(2)conversion,and long-term stability.Moreover,considering the tunable synergetic effects between the isolated cations and NPs,the developed approach offers a general guideline to design more efficient CO_(2)-ODP catalysts,which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn4+cations for Zn2+cations in the MFI zeolite matrix.
文摘This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.
文摘This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.
文摘The present work relates to a numerical investigation of double diffusive mixed convection around a horizontal annulus with a finned inner cylinder.The solutal and thermal buoyancy forces are sustained by maintaining the inner and outer cylinders at uniform temperatures and concentrations.Buoyancy effects are also considered,with the Boussinesq approximation.The forced convection effect is induced by the outer cylinder rotating with an angular velocity(ω)in an anti-clockwise direction.The studies are made for various combinations of dimensionless numbers;buoyancy ratio number(N),Lewis number(Le),Richardson number(Ri)and Grashof number(Gr).The isotherms,isoconcentrations and streamlines as well as both average and local Nusselt and Sherwood numbers were studied.A finite volume scheme is adopted to solve the transport equations for continuity,momentum,energy and mass transfer.The results indicate that the use of fins on the inner cylinder with outer cylinder rotation,significantly improves the heat and mass transfer in the annulus.
文摘This paper numerically investigates the effect of the location of a horizontal fin on the melting of a phase change material(PCM)inside a rectangular enclosure heated by multiple discrete pulsed protruding heat sources.The fin and the phase change material filling the enclosure store the thermal energy extracted from the heat sources,in sensible and latent forms.The heat sources are assumed to simulate electronic components undergoing a superheating technical issue.By extracting heat from the electronics,the PCM plays the role of a heat sink.To analyze the thermal behavior and predict the cooling performance of the proposed cooling system,we derive a nonlinear mathematical model based on mass,momentum and energy conservation laws.Several numerical investigations are conducted to quantify the influence of the fin position on the thermal behavior and the cooling performance of the heat sink.Predictions include the transient maximum temperature occurring inside the heat sources and the liquid volume.A comparison between our numerical results and experimental data selected from the literature shows a good agreement.The main conclusion is that the presence of the fin leads to a slight increase in the melting time.
基金financially supported by the National Natural Science Foundation of China(Grant No.51876147)。
文摘The heat storage performance of latent heat storage systems is not good due to the poor thermal conductivity of phase change materials.In this paper,a new type of pointer-shaped fins combining rectangular and triangular fins has been employed to numerically simulate the melting process in the heat storage tank,and the fin geometry parameter effects on heat storage performance have been studied.The results indicate that compared with the bare tube and the rectangular finned tank,the melting time of the phase change material in the pointer-shaped finned tank is reduced by 64.2%and 15.1%,respectively.The closer the tip of the triangular fin is to the hot wall,the better the heat transfer efficiency.The optimal height of the triangular fin is about 8 mm.Increasing the number of fins from 4 to 6 and from 6 to 8 reduces the melting time by 16.0%and 16.7%respectively.However,increasing the number of fins from 8 to 10 only reduces the melting time by 8.4%.When the fin dimensionless length is increased from 0.3 to 0.5 and from 0.5 to 0.7,the melting time is shortened by 17.5%and 13.0%.But the melting time is only reduced by 2.9%when the dimensionless fin length is increased from 0.7 to 0.9.For optimising the design of the thermal storage system,the results can provide a reference value.
基金supported by the China Postdoctoral Science Foundation(Grant No.2020M672344)。
文摘Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which can provide different grades of thermal energy with two heat transfer fluids(oil and water),is designed to improve thermal efficiency.In this FPTR-IT,an inner tube and straight fins are employed to respectively lessen heat loss at upper and lower parts of the absorber.Based on the design,a numerical model is developed to investigate its performance.Comparisons with other PTRs indicate that the FPTR-IT can combine the advantages of PTR with inner tube and finned PTR and obtain the best performance.Moreover,performance evaluation under broad ranges of direct normal irradiances(300–1000 W/m^(2)),flow rates(50–250 L/min)and inlet temperatures(400–600 K)of oil as well as flow rates(3.6–10 L/min)and inlet temperatures(298.15–318.15 K)of water is investigated.Compared with conventional PTR,heat loss is reduced by 20.7%–63.2%and total efficiency is improved by 0.03%–4.27%.Furthermore,the proportions of heat gains for water and oil are located in 8.3%–73.9%and-12.0%–64.3%,while their temperature gains are located in 11.6–37.9 K and-1.2–19.6 K,respectively.Thus,the proposed FPTR-IT may have a promising application prospect in remote arid areas or islands to provide different grades of heat for electricity and freshwater production.
基金The work was supported by the Natural Science Foundation of Shaanxi Province(No.2018JM5084)“the 13th Five-Year”National Science and Technology Major Project of China(No.2017YFC0702202)+1 种基金the Shaanxi Key Science and Technology Innovative Tea m Project(No.2016KCT-22)the Fundamental Research Funds for the Central Universities(CHD300102289203).
文摘In this article,a new evaporative condenser with an annular elliptic firmed tube heat exchanger that includes a round inner tube and elliptic outer finned tube was designed and analyzed.The refrigerant flows between the round inner tube and the elliptic outer tube,and it simultaneously exchanges heat with the cooling water in the inner tube,the spray water,and the cooling air flowing past the outer tube.Using field measurement for the traditional round finned tube evaporative condenser in the Futong Metro Station of Line 14 in Beijing,China,the theoretical heat transfer performance of the annular elliptic finned tube evaporative condenser was analyzed and simulated.Compared with a round finned tube heat exchanger,the heat exchange capacity of the annular elliptic finned tube increased by 2.34%to 9.28%;the total heat transfer coefficient increased by 47.42%,and the power consumption of the fan in the air-conditioning system with an annular elliptic finned tube heat exchanger decreased by 11.18%to 14.65%.Therefore,the energy-saving performance and the heat transfer performance of the new annular elliptic finned tube heat exchanger were enhanced compared to the round finned tube heat exchanger.
基金Supported by the National Natural Science Foundation of China(Nos.31872586,42076118)the Major Project of Science,Technology and Innovation 2025 in Ningbo City(No.2021Z003)the K.C.Wong Magna Fund in Ningbo University。
文摘The Tbx family is first known through the study of their functions in the body and limbs,and its members Tbx4 and Tbx5 genes are important factors in determining the characteristics of the appendages.Pampus argenteus is one of the important economical marine fishes widely distributed in offshore areas.Therefore,it is necessary to study the role of Tbx family genes in the deletion of pelvic fin in P.argenteus.In this study,we cloned Tbx4 and Tbx5 cDNA sequence of P.argenteus(GenBank:MH709128 and MH712458).The Western blot and real time PCR were used to detect the expressions of Tbx4 and Tbx5 in different developmental stages and tissues of P.argenteus.In addition,whole-mount in-situ hybridization was used to study the localization of Tbx4 and Tbx5 genes in different developmental stages of P.argenteus.Results show that the translation of Tbx4 mRNA was inhibited during the critical period of pelvic fin development.Among different tissues,Tbx4 protein levels were the lowest in the abdominal epithelium,and even lower than that in the pectoral fin,suggesting that the protein expression was also inhibited in the abdominal epithelium of adult P.argenteus.Therefore,the results indicated that upstream genes regulation led to the key stage-specific and low expression of Tbx4 during pelvic fin development and in the abdominal epithelium.
基金Project supported by the DST-FIST Program for Higher Education Institutions of India(No. SR/FST/MS-I/2018/23(C))。
文摘The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.
文摘An investigation of the decoupled thermal–hydraulic analysis of a separated heat pipe spent fuel pool passive cooling system(SFS)is essential for practical engineering applications.Based on the principles of thermal and mass balance,this study decoupled the heat transfer processes in the SFS.In accordance with the decoupling conditions,we modeled the spent fuel pool of the CAP1400 pressurized water reactor in Weihai and used computational fluid dynamics to explore the heat dissipation capacity of the SFS under different air temperatures and wind speeds.The results show that the air-cooled separated heat pipe radiator achieved optimal performance at an air temperature of 10℃ or wind speed of 8 m/s.Fitted equations for the equivalent thermal conductivity of the separated heat pipes with the wind speed and air temperature we obtained according to the thermal resistance network model.This study is instructive for the actual operation of an SFS.
基金Zhejiang Provincial Natural Science of China (Grant No.LQ20E060003)Zhejiang Provincial Basic Public Welfare Research Project of China (Grant No.LGG20E050007)+3 种基金Key Projects of Hangzhou Agricultural and Social Development Research Program of China (Grant No.20212013B04)Projects of Hangzhou Agricultural and Social Development Research Program of China (Grant Nos.20201203B128,20212013B04)Scientific Research Foundation of Zhejiang University City College of China (Grant Nos.J-202116,X-202205)2021 Teacher Professional Development Program for Domestic Visiting Scholars in Universities of China (Grant No.FX2021105)。
文摘The performance of an integrated thermal management system signi?cantly in?uences the stability of special-purpose vehicles;thus,enhancing the heat transfer of the radiator is of great signi?cance.Common research methods for radiators include?uid mechanics numerical simulations and experimental measurements,both of which are time-consuming and expensive.Applying the surrogate model to the analysis of the?ow and heat transfer in louvered?ns can effectively reduce the computational cost and obtain more data.A simpli?ed louvered-?n heat transfer unit was established,and computational?uid dynamics(CFD)simulations were conducted to obtain the?ow and heat transfer characteristics of the geometric structure.A three-factor and six-level orthogonal design was established with three structural parameters:angleθ,length a,and pitch L_p of the louvered?ns.The results of the orthogonal design were subjected to a range analysis,and the effects of the three parametersθ,a,and L_p on the j,f,and JF factors were obtained.Accordingly,a proxy model of the heat transfer performance for louvered?ns was established based onthe arti?cial neural network algorithm,and the model was trained with the data obtained by the orthogonal design.Finally,the?n structure with the largest JF factor was realized.Compared with the original model,the optimizedmodel improved the heat transfer factor j by 2.87%,decreased the friction factor f by 30.4%,and increased the comprehensive factor JF by 15.7%.
基金Department of Science and Technology,Govt of India for their support under the DST-FIST Programme for HEIs(No.SR/FST/MS-I/2018/23(C))the University Grants Commission,New Delhi,India(No.CSIR-UGC NET DEC.2019)/(Student ID:191620111468)for the financial support in the form of UGC-Junior Research Fellowship。
文摘A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current article.The periodic variation in the fin base temperature is taken into account along with the temperature sensitive thermal conductivity and convective heat transfer coefficients.The modeled problem,which is resolved into a non-linear partial differential equation(PDE),is made dimensionless and solved by employing the finite difference method(FDM).The results are displayed through graphs and discussed.The effects of amplitude,frequency of oscillation,wet nature,Peclet number,and other relevant quantities on the distribution of temperature through the fin length and with the dimensionless time are investigated.It is deciphered that the periodic heat transfer gives rise to the wavy nature of the fin thermal profile against time.The analysis is beneficial in the design of fin structures for applications like solar collectors,space/airborne applications,and refrigeration industries.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12035019,12105339,and62174180)the Opening Special Foundation of State Key Laboratory of Intense Pulsed Radiation Simulation and Effect,China(Grant No.SKLIPR2113)。
文摘The variations of single event transient(SET)pulse width of high-LET heavy ion irradiation in 16-nm-thick bulk silicon fin field-effect transistor(Fin FET)inverter chains with different driven strengths are measured at different temperatures.Three-dimensional(3D)technology computer-aided design simulations are carried out to study the SET pulse width and saturation current varying with temperature.Experimental and simulation results indicate that the increase in temperature will enhance the parasitic bipolar effect of bulk Fin FET technology,resulting in the increase of SET pulse width.On the other hand,the increase of inverter driven strength will change the layout topology,which has a complex influence on the SET temperature effects of Fin FET inverter chains.The experimental and simulation results show that the device with the strongest driven strength has the least dependence on temperature.
文摘An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.