This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing chara...This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing characteristics is revealed,and an energy-efficient zoned electric heating anti-icing strategy is proposed.A threedimensional grille model is constructed to systematically analyze the effects of environmental temperature(from−20℃to−4℃),droplet diameter(from 50μm to 500μm),and liquid water content(from 0.5 g/m³to 8 g/m³)on icing rates and blockage of the flow channel.The results indicate that low temperature and high liquid water content significantly exacerbate icing.Under the condition of an environmental temperature of−20℃,droplet diameter of 500μm,and liquid water content of 8 g/m³,the flow channel blockage ratio reaches 30.95%within 10 min.Additionally,as droplet diameter increases,the droplet impingement and icing regions become more concentrated toward the leading edge of blades.To mitigate grille icing in cold environments,an electric heating film configuration is employed for thermal protection.Optimization of the heating strategy reveals that the zoned heating approach,compared to the initial uniform heating scheme,effectively homogenizes surface temperature distribution while reducing total power consumption by 37.47%.This study validates the engineering applicability of the zoned electric heating anti/de-icing strategy,providing theoretical and technical support for the design of anti-icing systems in ship power systems operating in cold maritime regions.展开更多
Layup temperature is a vital factor that affects the production quality of automated fiber placement for thermoset composites.For high quality production,this paper proposes a new prediction model of layup temperature...Layup temperature is a vital factor that affects the production quality of automated fiber placement for thermoset composites.For high quality production,this paper proposes a new prediction model of layup temperature by considering the structure of infrared heater of automatic fiber placement equipment.The model was first verified by comparing with the temperature results of layup experiments.Then a prediction on the effects of heater structure arrangement on layup temperature was conducted in the model.The research shows that the length of infrared tube and the radian of reflective-film have significant influences,rather than other parameters.According to this investigation,a heater structure-based heating strategy was presented in the paper to efficiently achieve constant temperature control in variable speed layup process.展开更多
The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The ...The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The present study proposes a hybrid heating approach combining active heating with passive insulation.Conceptual experiments were conducted to investigate the effects of phase change materials(PCMs),inlet water temperature,and intermittent pump startup strategies on battery performance.The obtained experimental results demonstrate that low temperatures lead to increased electrochemical impedance and reduced charge–discharge capacity in batteries.Notably,charge transfer resistance of 162 mΩwas observed at-30℃.Herein,the developed PCM-based battery heating system effectively extended the operational capacity of batteries in cold driving conditions and maintained battery warmth by leveraging the superior heat storage capability of the PCM.Additionally,after the switch off of the heating system,the charge capacity of the battery exceeded 80%owing to latent heat.The use of an intermittent heating strategy not only allowed to conserve energy but also maintained adequate heat storage within the battery module.At-30℃,this strategy enhanced the power efficiency of the cooling system by 35.94%with a reduction in capacity of only 0.8%compared to the continuous strategy.展开更多
This paper discusses the design and building process of a net-zero energy solar-powered house developed for the 2013 Solar Decathlon competition to promote high-performance design while using traditional passive strat...This paper discusses the design and building process of a net-zero energy solar-powered house developed for the 2013 Solar Decathlon competition to promote high-performance design while using traditional passive strategies.This project,sponsored by the Department of Energy,brought together students from architecture,engineering,and marketing departments to design and build the house of the future.The challenge was to design a net-zero energy completely solar-powered house that is economically viable,aesthetically pleasant,and completely functional as well.Given that a net-zero energy building will rely on the functional interdependency of a building’s passive and active elements,the UNC Charlotte entry-the UrbanEden house-tried to effectively integrate those elements and deliver a best practice.To that end,the building envelope embraced passive strategies to minimize the annual heating and cooling loads and to optimize natural lighting.Several design ideas were tested via energy simulation to optimize energy and comfort performance.The estimated energy demand led into the design of the photovoltaic system,which has the dual function of producing energy and acting as a shading device.The modular configuration of the house accommodated the transportation of the house across the country while enhancing the future expansion of the house for bigger size applications.Daylighting simulation was performed to finalize the building openings and address the lighting needs.This paper reports a way of effectively designing and constructing a net-zero energy,comfortable,and affordable solar house.展开更多
基金supported in part by the Ship Preliminary Research Project (No.3020401020102)。
文摘This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing characteristics is revealed,and an energy-efficient zoned electric heating anti-icing strategy is proposed.A threedimensional grille model is constructed to systematically analyze the effects of environmental temperature(from−20℃to−4℃),droplet diameter(from 50μm to 500μm),and liquid water content(from 0.5 g/m³to 8 g/m³)on icing rates and blockage of the flow channel.The results indicate that low temperature and high liquid water content significantly exacerbate icing.Under the condition of an environmental temperature of−20℃,droplet diameter of 500μm,and liquid water content of 8 g/m³,the flow channel blockage ratio reaches 30.95%within 10 min.Additionally,as droplet diameter increases,the droplet impingement and icing regions become more concentrated toward the leading edge of blades.To mitigate grille icing in cold environments,an electric heating film configuration is employed for thermal protection.Optimization of the heating strategy reveals that the zoned heating approach,compared to the initial uniform heating scheme,effectively homogenizes surface temperature distribution while reducing total power consumption by 37.47%.This study validates the engineering applicability of the zoned electric heating anti/de-icing strategy,providing theoretical and technical support for the design of anti-icing systems in ship power systems operating in cold maritime regions.
基金supported by the National Natural Science Foundation of China(No.51805476)the Fundamental Research Funds for the Central Universities of China(No.2019FZA4001)the Major Research plan of the National Natural Science Foundation of China(No.91748204).
文摘Layup temperature is a vital factor that affects the production quality of automated fiber placement for thermoset composites.For high quality production,this paper proposes a new prediction model of layup temperature by considering the structure of infrared heater of automatic fiber placement equipment.The model was first verified by comparing with the temperature results of layup experiments.Then a prediction on the effects of heater structure arrangement on layup temperature was conducted in the model.The research shows that the length of infrared tube and the radian of reflective-film have significant influences,rather than other parameters.According to this investigation,a heater structure-based heating strategy was presented in the paper to efficiently achieve constant temperature control in variable speed layup process.
基金supported by the National Natural Science Foundation of China(Grant No.52090062)。
文摘The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The present study proposes a hybrid heating approach combining active heating with passive insulation.Conceptual experiments were conducted to investigate the effects of phase change materials(PCMs),inlet water temperature,and intermittent pump startup strategies on battery performance.The obtained experimental results demonstrate that low temperatures lead to increased electrochemical impedance and reduced charge–discharge capacity in batteries.Notably,charge transfer resistance of 162 mΩwas observed at-30℃.Herein,the developed PCM-based battery heating system effectively extended the operational capacity of batteries in cold driving conditions and maintained battery warmth by leveraging the superior heat storage capability of the PCM.Additionally,after the switch off of the heating system,the charge capacity of the battery exceeded 80%owing to latent heat.The use of an intermittent heating strategy not only allowed to conserve energy but also maintained adequate heat storage within the battery module.At-30℃,this strategy enhanced the power efficiency of the cooling system by 35.94%with a reduction in capacity of only 0.8%compared to the continuous strategy.
文摘This paper discusses the design and building process of a net-zero energy solar-powered house developed for the 2013 Solar Decathlon competition to promote high-performance design while using traditional passive strategies.This project,sponsored by the Department of Energy,brought together students from architecture,engineering,and marketing departments to design and build the house of the future.The challenge was to design a net-zero energy completely solar-powered house that is economically viable,aesthetically pleasant,and completely functional as well.Given that a net-zero energy building will rely on the functional interdependency of a building’s passive and active elements,the UNC Charlotte entry-the UrbanEden house-tried to effectively integrate those elements and deliver a best practice.To that end,the building envelope embraced passive strategies to minimize the annual heating and cooling loads and to optimize natural lighting.Several design ideas were tested via energy simulation to optimize energy and comfort performance.The estimated energy demand led into the design of the photovoltaic system,which has the dual function of producing energy and acting as a shading device.The modular configuration of the house accommodated the transportation of the house across the country while enhancing the future expansion of the house for bigger size applications.Daylighting simulation was performed to finalize the building openings and address the lighting needs.This paper reports a way of effectively designing and constructing a net-zero energy,comfortable,and affordable solar house.
