The ability to measure the very high heat fluxes that typically occur during the hypersonic re-entry phase of space vehicles is generally considered a subject of great importance in the aerospace field.Most of the sen...The ability to measure the very high heat fluxes that typically occur during the hypersonic re-entry phase of space vehicles is generally considered a subject of great importance in the aerospace field.Most of the sensors used for these measurements need to be checked periodically and re-calibrated accordingly.Another bottleneck relates to the need to procure thermal sources that are able to generate reliable reference heat fluxes in the range between 100 and 1000 kW/m^(2)(as order of magnitude).In the present study,a method is presented by which,starting from a calibration system with a capacity of approximately 500 kW/m^(2) only,heat fluxes in the range of interest for hypersonic applications are generated.The related procedure takes advantage of established standards for the characterization of a radiative heat flux.It also builds on the hybrid radiative-convective nature of typical hypersonic heat fluxes and the yet poorly explored possibility to use convective sources of heat to produce high-intensity fluxes.The reliability of such a strategy has been tested using a high enthalpy supersonic flow facility relying on an electric arc-heater and pure Nitrogen as work gas.Stagnation-point heat fluxes have been successfully measured(with reasonable accuracy)in the range between 600 and 1500 kW/m^(2) for values of the centerline enthalpy spanning the interval from to 6 to 24 MJ/kg.展开更多
Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- ...Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- mostat module maintains the sensor temperature invariable, and the heat flux sensor（Peltier device） detects the heat flux temperature difference between the thermostat module and the object surface. Two different modes of the heat flux tactile sensor are proposed, and they are simulated and experimented for different material objects. The results indicate that the heat flux tactile sensor can effectively identify different thermal properties.展开更多
To measure heat flux on the sharp leading edge and other surface with very small curvature radius in the wind tunnel, Hong-Ru Yu proposed a novel design of integral type heat flux sensor. Compared with the traditional...To measure heat flux on the sharp leading edge and other surface with very small curvature radius in the wind tunnel, Hong-Ru Yu proposed a novel design of integral type heat flux sensor. Compared with the traditional heat flux sensor, the integral type heat flux sensor improved spatial resolution up to an order of magnitude, and the size of the sensing elements has been minimized to 0.1 mm successfully, which satisfied the heat flux measurement requirements at R0.5 mm pointed cone stagnation point. A constantan film was used as the contact layer of the integral heat flux sensor, which was prepared by electron beam coevaporation method. The influence of sensor structure on the accuracy of measurement was analyzed using numerical calculation. The measurement results in shock wave wind tunnel indicated that the response frequency was about100 kHz and the repeatability error was less than 10 %.展开更多
The need for developing accurate quenching models requires an extensive experimental database that includes surface heat flux characterization. Quantification of the quenching process permits i) the development of hig...The need for developing accurate quenching models requires an extensive experimental database that includes surface heat flux characterization. Quantification of the quenching process permits i) the development of high-quality heat treated products, ii) the evaluation of new quenchants and quenchant systems, and iii) the evaluation of quenchant quality over usage time. The surface heat transfer coefficient (or heat flux) is rarely measured, calculated or modeled in sufficient detail for real scientific use. Many single-thermocouple based probes are designed for the purpose of measuring the cooling power of a liquid quenchant or for monitoring quenchant quality. Lumped based probes are sufficient for these types of applications. However, the lack of sufficient distributed detail impedes the development of future high-quality heat-treated products. Frankel and his coworkers are developing a new family of transient thermal-rate sensors that will improve both diagnostic and real-time analyzes in heat transfer studies. Analyzes have been performed indicating that there exists a novel, thermal-rate sensor hierarchy that stabilizes predictions when used with analysis. This concept can be used for investigating both (i) direct surface heat transfer effects, and (ii) projective surface analysis based on embedded sensors. This new sensor family includes the ability to measure temperature, T; heat flux, q"; and their temporal derivatives, i.e., dT/dt, d^T/dt2 and dq’Vdt.展开更多
A new type of sensor with the flexible substrate is introduced.It is applicable in measuring instantaneous heat flux on the model surface in a hypersonic shock tunnel.The working principle,structure and manufacture pr...A new type of sensor with the flexible substrate is introduced.It is applicable in measuring instantaneous heat flux on the model surface in a hypersonic shock tunnel.The working principle,structure and manufacture process of the sensor are presented.The substrate thickness and the dynamic response parameter of the sensor are calculated.Because this sensor was successfully used in measuring the instantaneous heat flux on the surface of a flat plate in a detonation-driven shock tunnel,it may be effective in measuring instantaneous heat flux on the model surface.展开更多
文摘The ability to measure the very high heat fluxes that typically occur during the hypersonic re-entry phase of space vehicles is generally considered a subject of great importance in the aerospace field.Most of the sensors used for these measurements need to be checked periodically and re-calibrated accordingly.Another bottleneck relates to the need to procure thermal sources that are able to generate reliable reference heat fluxes in the range between 100 and 1000 kW/m^(2)(as order of magnitude).In the present study,a method is presented by which,starting from a calibration system with a capacity of approximately 500 kW/m^(2) only,heat fluxes in the range of interest for hypersonic applications are generated.The related procedure takes advantage of established standards for the characterization of a radiative heat flux.It also builds on the hybrid radiative-convective nature of typical hypersonic heat fluxes and the yet poorly explored possibility to use convective sources of heat to produce high-intensity fluxes.The reliability of such a strategy has been tested using a high enthalpy supersonic flow facility relying on an electric arc-heater and pure Nitrogen as work gas.Stagnation-point heat fluxes have been successfully measured(with reasonable accuracy)in the range between 600 and 1500 kW/m^(2) for values of the centerline enthalpy spanning the interval from to 6 to 24 MJ/kg.
基金Supported by the National High Technology Research and Development Program of China(″863″Program)(2009AA01Z314,2009AA01Z311)the Jiangsu Province Natural Science Foundation(BK2009272)theJiangsu Province″333″Program~~
文摘Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- mostat module maintains the sensor temperature invariable, and the heat flux sensor（Peltier device） detects the heat flux temperature difference between the thermostat module and the object surface. Two different modes of the heat flux tactile sensor are proposed, and they are simulated and experimented for different material objects. The results indicate that the heat flux tactile sensor can effectively identify different thermal properties.
文摘To measure heat flux on the sharp leading edge and other surface with very small curvature radius in the wind tunnel, Hong-Ru Yu proposed a novel design of integral type heat flux sensor. Compared with the traditional heat flux sensor, the integral type heat flux sensor improved spatial resolution up to an order of magnitude, and the size of the sensing elements has been minimized to 0.1 mm successfully, which satisfied the heat flux measurement requirements at R0.5 mm pointed cone stagnation point. A constantan film was used as the contact layer of the integral heat flux sensor, which was prepared by electron beam coevaporation method. The influence of sensor structure on the accuracy of measurement was analyzed using numerical calculation. The measurement results in shock wave wind tunnel indicated that the response frequency was about100 kHz and the repeatability error was less than 10 %.
文摘The need for developing accurate quenching models requires an extensive experimental database that includes surface heat flux characterization. Quantification of the quenching process permits i) the development of high-quality heat treated products, ii) the evaluation of new quenchants and quenchant systems, and iii) the evaluation of quenchant quality over usage time. The surface heat transfer coefficient (or heat flux) is rarely measured, calculated or modeled in sufficient detail for real scientific use. Many single-thermocouple based probes are designed for the purpose of measuring the cooling power of a liquid quenchant or for monitoring quenchant quality. Lumped based probes are sufficient for these types of applications. However, the lack of sufficient distributed detail impedes the development of future high-quality heat-treated products. Frankel and his coworkers are developing a new family of transient thermal-rate sensors that will improve both diagnostic and real-time analyzes in heat transfer studies. Analyzes have been performed indicating that there exists a novel, thermal-rate sensor hierarchy that stabilizes predictions when used with analysis. This concept can be used for investigating both (i) direct surface heat transfer effects, and (ii) projective surface analysis based on embedded sensors. This new sensor family includes the ability to measure temperature, T; heat flux, q"; and their temporal derivatives, i.e., dT/dt, d^T/dt2 and dq’Vdt.
文摘A new type of sensor with the flexible substrate is introduced.It is applicable in measuring instantaneous heat flux on the model surface in a hypersonic shock tunnel.The working principle,structure and manufacture process of the sensor are presented.The substrate thickness and the dynamic response parameter of the sensor are calculated.Because this sensor was successfully used in measuring the instantaneous heat flux on the surface of a flat plate in a detonation-driven shock tunnel,it may be effective in measuring instantaneous heat flux on the model surface.
