Ice accretion on surfaces of the aircraft and engine is a serious threat to the flight safety.In this paper,a novel hot air anti-icing method is proposed based on the porous foam.Taking the NACA0012 airfoil as an exam...Ice accretion on surfaces of the aircraft and engine is a serious threat to the flight safety.In this paper,a novel hot air anti-icing method is proposed based on the porous foam.Taking the NACA0012 airfoil as an example,the traditional thermal protection structure is proved to exist the deficiency in balancing the heat exchange caused by route loss of the heat.By dividing the hot chamber into multiple regions to fill with various foam metal,flow resistance characteristics and heat transfer characteristics for this protection mode are analyzed in order to derive the maximized benefit in anti-icing process.The calculation results reveal that,under the same condition,the region filled with foamed copper not only improves the temperature uniformity on the anti-icing area,but also achieves a better protection effect for enhancing heat transfer between the tube and the hot gas,averagely above 20℃higher than it without porous foam filling in surface temperature.Additionally,the minimum mass flow rate of the protection hot air is reduced by 16.7%.The gratifying efficiency of the porous filler in fortifying heat transfer confirms the potential of replacing the efficient but complex heat transfer design with simple structure filled with foam metal.展开更多
Thermal management has become a significant concern in the design of advanced air vehicles.However,an effective evaluation method is needed when designers need to evaluate aircraft thermal management systems comprehen...Thermal management has become a significant concern in the design of advanced air vehicles.However,an effective evaluation method is needed when designers need to evaluate aircraft thermal management systems comprehensively.This paper proposes an evaluation method in which several evaluation directions concerned with thermal management systems(TMSs) are put forward to form an evaluation index system.The effect of temperature control,heat sink utilization efficiency,energy utilization efficiency,flight performance penalty,thermal endurance,space occupancy ratio,and economy are chosen as the direction of evaluation for TMS,considering its primary function,system performance,and impact on aerial vehicles.This method is comprehensive,intuitive,and user-friendly,along with the intensely subjective user-defined weight parameters,which provide rational metrics for thermal management techniques involved in aerial vehicles.The evaluation method could potentially be helpful for designers to comprehensively analyze the performance of aircraft thermal management systems and provide a basis for practical application.Two examples are provided to demonstrate the application of the method to evaluating TMS comprehensively.展开更多
An automatic cooling device has been developed by using a temperature-sensitive magnetic fluid as the coolant. A particle image velocimetry (PIV) system was used to measure the flow velocity of the fluid inside the lo...An automatic cooling device has been developed by using a temperature-sensitive magnetic fluid as the coolant. A particle image velocimetry (PIV) system was used to measure the flow velocity of the fluid inside the loop. The efficiency of the device under varying conditions such as the heat load and the power of cooling were ex- perimentally investigated. The effect of cooperation between external magnetic field and thermal field on the performance of the device was studied. As expected, a continuous flow induced by the thermal and magnetic field was observed in the loop, where heat was transferred by the circulating magnetic fluid. The synergic effect between the magnetic field and the temperature gradient has impact on the performance of the device.展开更多
文摘Ice accretion on surfaces of the aircraft and engine is a serious threat to the flight safety.In this paper,a novel hot air anti-icing method is proposed based on the porous foam.Taking the NACA0012 airfoil as an example,the traditional thermal protection structure is proved to exist the deficiency in balancing the heat exchange caused by route loss of the heat.By dividing the hot chamber into multiple regions to fill with various foam metal,flow resistance characteristics and heat transfer characteristics for this protection mode are analyzed in order to derive the maximized benefit in anti-icing process.The calculation results reveal that,under the same condition,the region filled with foamed copper not only improves the temperature uniformity on the anti-icing area,but also achieves a better protection effect for enhancing heat transfer between the tube and the hot gas,averagely above 20℃higher than it without porous foam filling in surface temperature.Additionally,the minimum mass flow rate of the protection hot air is reduced by 16.7%.The gratifying efficiency of the porous filler in fortifying heat transfer confirms the potential of replacing the efficient but complex heat transfer design with simple structure filled with foam metal.
基金supported by the 1912 Project of China (Grant No.2019-JCJQ-DA-001-108)。
文摘Thermal management has become a significant concern in the design of advanced air vehicles.However,an effective evaluation method is needed when designers need to evaluate aircraft thermal management systems comprehensively.This paper proposes an evaluation method in which several evaluation directions concerned with thermal management systems(TMSs) are put forward to form an evaluation index system.The effect of temperature control,heat sink utilization efficiency,energy utilization efficiency,flight performance penalty,thermal endurance,space occupancy ratio,and economy are chosen as the direction of evaluation for TMS,considering its primary function,system performance,and impact on aerial vehicles.This method is comprehensive,intuitive,and user-friendly,along with the intensely subjective user-defined weight parameters,which provide rational metrics for thermal management techniques involved in aerial vehicles.The evaluation method could potentially be helpful for designers to comprehensively analyze the performance of aircraft thermal management systems and provide a basis for practical application.Two examples are provided to demonstrate the application of the method to evaluating TMS comprehensively.
基金Supported by the National Natural Science Foundation of China (Grant No. 50436020)
文摘An automatic cooling device has been developed by using a temperature-sensitive magnetic fluid as the coolant. A particle image velocimetry (PIV) system was used to measure the flow velocity of the fluid inside the loop. The efficiency of the device under varying conditions such as the heat load and the power of cooling were ex- perimentally investigated. The effect of cooperation between external magnetic field and thermal field on the performance of the device was studied. As expected, a continuous flow induced by the thermal and magnetic field was observed in the loop, where heat was transferred by the circulating magnetic fluid. The synergic effect between the magnetic field and the temperature gradient has impact on the performance of the device.
