Metal foil strain gauges remain the state-of-the-art transducers for wind tunnel balances.While strain gauge technology is very mature,piezoresistive semiconductor sensors offer alternatives that are worth exploring t...Metal foil strain gauges remain the state-of-the-art transducers for wind tunnel balances.While strain gauge technology is very mature,piezoresistive semiconductor sensors offer alternatives that are worth exploring to assess their unique benefits,such as better strain resolution and accuracy,which would enable balances to be designed with higher factors to safety and hence longer fatigue lifetimes.A new three-component balance,based on temperature compensated semiconductor strain gauges,is designed,calibrated and tested in a hypersonic low density wind tunnel.The static accuracy of the semiconductor balance is calibrated better than 0.3%FS,and the dynamic accuracy of the balance is established using a HB-2 standard model in a Mach 12 hypersonic flow.Good experimental repeatability is confirmed to be better than 2.5%FS,and the effectiveness of the balance is demonstrated by comparing the forces and moments of measured data with computational fluid dynamics simulations,as well as reference wind tunnel results under similar conditions.展开更多
In order to visualize the rarefied flow field in aΦ1m hypersonic low-density wind tunnel,an electric glow discharge technique based on high frequency excited power has been developed.Firstly,finite element simulation...In order to visualize the rarefied flow field in aΦ1m hypersonic low-density wind tunnel,an electric glow discharge technique based on high frequency excited power has been developed.Firstly,finite element simulation analysis has been carried out,and it is concluded that the breakdown voltage can be reduced by using high frequency power supply;then an electric glow discharge apparatus has been fabricated,and the discharge images were compared with simulations;besides,a clear flow field around HB-1 standard model has been observed using this technology;finally,the influence of glow discharge on the flow field,as well as the differences between direct current and high frequency electric glow discharges is discussed at the end of this paper.展开更多
Advanced sensing techniques are in big demand for applications in hypersonic wind tunnel harsh environments,such as aero(thermo)dynamics measurements,thermal protection of aircraft structures,air-breathing propulsion,...Advanced sensing techniques are in big demand for applications in hypersonic wind tunnel harsh environments,such as aero(thermo)dynamics measurements,thermal protection of aircraft structures,air-breathing propulsion,light-weighted and highstrength materials,etc.In comparison with traditional electromechanical or electronic sensors,the fiber optic sensors have relatively high potential to work in hypersonic wind tunnel,due to the capability of responding to a wide variety of parameters,high resolution,miniature size,high resistant to electromagnetic and radio frequency interferences,and multiplexing,and so on.This article has classified and summarized the research status and the representative achievement on the fiber optic sensing technologies,giving special attention to the summary of research status on the popular Fabry-Perot interferometric,fiber Bragg gratings and(quasi)distributed fiber optic sensors working in hypersonic wind tunnel environment,and discussed the current problems in special optical fiber sensing technologies.This article would be regarded as reference for the researchers in hypersonic wind tunnel experiment field.展开更多
文摘Metal foil strain gauges remain the state-of-the-art transducers for wind tunnel balances.While strain gauge technology is very mature,piezoresistive semiconductor sensors offer alternatives that are worth exploring to assess their unique benefits,such as better strain resolution and accuracy,which would enable balances to be designed with higher factors to safety and hence longer fatigue lifetimes.A new three-component balance,based on temperature compensated semiconductor strain gauges,is designed,calibrated and tested in a hypersonic low density wind tunnel.The static accuracy of the semiconductor balance is calibrated better than 0.3%FS,and the dynamic accuracy of the balance is established using a HB-2 standard model in a Mach 12 hypersonic flow.Good experimental repeatability is confirmed to be better than 2.5%FS,and the effectiveness of the balance is demonstrated by comparing the forces and moments of measured data with computational fluid dynamics simulations,as well as reference wind tunnel results under similar conditions.
基金supported by the National Natural Science Foundation of China(NSFC)(Project Nr.:11802329).
文摘In order to visualize the rarefied flow field in aΦ1m hypersonic low-density wind tunnel,an electric glow discharge technique based on high frequency excited power has been developed.Firstly,finite element simulation analysis has been carried out,and it is concluded that the breakdown voltage can be reduced by using high frequency power supply;then an electric glow discharge apparatus has been fabricated,and the discharge images were compared with simulations;besides,a clear flow field around HB-1 standard model has been observed using this technology;finally,the influence of glow discharge on the flow field,as well as the differences between direct current and high frequency electric glow discharges is discussed at the end of this paper.
基金the National Natural Science Foundation of China(NSFC)(Project Nr.:2012YQ25002,11802329).
文摘Advanced sensing techniques are in big demand for applications in hypersonic wind tunnel harsh environments,such as aero(thermo)dynamics measurements,thermal protection of aircraft structures,air-breathing propulsion,light-weighted and highstrength materials,etc.In comparison with traditional electromechanical or electronic sensors,the fiber optic sensors have relatively high potential to work in hypersonic wind tunnel,due to the capability of responding to a wide variety of parameters,high resolution,miniature size,high resistant to electromagnetic and radio frequency interferences,and multiplexing,and so on.This article has classified and summarized the research status and the representative achievement on the fiber optic sensing technologies,giving special attention to the summary of research status on the popular Fabry-Perot interferometric,fiber Bragg gratings and(quasi)distributed fiber optic sensors working in hypersonic wind tunnel environment,and discussed the current problems in special optical fiber sensing technologies.This article would be regarded as reference for the researchers in hypersonic wind tunnel experiment field.
