Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order...Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order calculus has the inherent advantage of easily jumping out of local extreme values;here,it is introduced into the particle-swarm algorithm to invert the true temperature.An improved adaptive-adjustment mechanism is applied to automatically adjust the current velocity order of the particles and update their velocity and position values,increasing the accuracy of the true temperature values.The results of simulations using the proposed algorithm were compared with three algorithms using typical emissivity models:the internal penalty function algorithm,the optimization function(fmincon)algorithm,and the conventional particle-swarm optimization algorithm.The results show that the proposed algorithm has good accuracy for true-temperature inversion.Actual experimental results from a rocket-motor plume were used to demonstrate that the true-temperature inversion results of this algorithm are in good agreement with the theoretical true-temperature values.展开更多
In general, the dependence of the logarithm of the emissivity upon wavelength is usually used in the treatment of data measured by multi-wavelength pyrometer. In this paper, the suitability of this expression for diff...In general, the dependence of the logarithm of the emissivity upon wavelength is usually used in the treatment of data measured by multi-wavelength pyrometer. In this paper, the suitability of this expression for different materials has been examined. Further more, an effective method for automatically searching the mathematical model between emissivity and wavelength has been procsed. The calculated results show that the accuracy is improved by using this data treatment method.展开更多
The measurement and control of high temperature play very important roles in national defense,military,scientific experiments,industrial and agricultural production.Photoelectric pyrometer is one of the important radi...The measurement and control of high temperature play very important roles in national defense,military,scientific experiments,industrial and agricultural production.Photoelectric pyrometer is one of the important radiation thermometers for non-contact temperature measurement.It has an important application in the field of high temperature measurement,and its performance directly affects the accuracy of temperature measurement.By improving the design of the detection optical system of the photoelectric pyrometer,the imaging performance of the photoelectric pyrometer can be improved effectively,and the temperature measurement accuracy can be improved.In this paper,the temperature measurement principle of photoelectric pyrometer,the wo rking principle of the detection optical system and the composition of the system are introduced.The optical components that affect the imaging of the optical system of the photoelectric pyrometer are analyzed.The optical pyrometer detection optical system is simulated by ZEMAX software,based on the analysis results,the Modulation Transfer Function(MTF)and the spot Diagram are used as the main evaluation criteria to optimize the design of the objective lens of the photoelectric pyrometer detection optical system.The imaging performance of the photoelectric pyrometer detection optical system and the accuracy of temperature measurement of the photoelectric pyrometer are improved by optimization design of the detection optical system.展开更多
In the study,the two-color pyrometer technique was used to measure the transient temperature field of emulsion explosives with different contents of TiH_(2)powders.The experimental results showed that the introduction...In the study,the two-color pyrometer technique was used to measure the transient temperature field of emulsion explosives with different contents of TiH_(2)powders.The experimental results showed that the introduction of TiH_(2)powders could significantly increase the explosion temperature and fireball duration of emulsion explosive.When emulsion explosives were ignited,the average explosion temperature of pure emulsion explosive continuously decreased while emulsion explosives added with TiH_(2)powders increased at first and then decreased.When the content of TiH_(2)powders was 6 mass%,the explosion average temperature reached its maximum value of 3095 K,increasing by 43.7%as compared with that of pure emulsion explosive.In addition,the results of air blast experiment and explosion heat test showed that the variation trends of shock wave parameters,explosion heat and theoretical explosion temperature of emulsion explosives with different contents of TiH_(2)powders were basically consistent with that of explosion temperature measured by the two-color pyrometer technique.In conclusion,the two-color pyrometer technique would be conducive to the formula design of emulsion explosive by understanding the explosion temperature characteristics.展开更多
An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature res...An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature responses of primary initiation FAE and secondary initiation FAE in real time. And the characteristics of their temperature history curves were compared and analyzed. The results show that the primary initiation FAE has higher explosion temperature and longer duration compared to the secondary initiation FAE.展开更多
A streaked optical pyrometer (SOP) is developed and calibrated for the measurement of the temperature of shocked materials. In order to achieve a higher relative sensitivity, a onechannel scheme is adopted for the s...A streaked optical pyrometer (SOP) is developed and calibrated for the measurement of the temperature of shocked materials. In order to achieve a higher relative sensitivity, a onechannel scheme is adopted for the system. The system is calibrated with a shocked step-shaped aluminum sample in the SG-III prototype laser facility. The relation between the count number in the detection system and the sample temperature is thus obtained, which can be adopted to infer the temperature of any shocked materials in future experiments.展开更多
In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algo...In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algorithm based on the methods of synchronous detection providing展开更多
A study of the fundamental properties of high-energy-density (HED) matter is of considerable important as it has wide application to various branches of the basic and applied science. The study will enable one to prob...A study of the fundamental properties of high-energy-density (HED) matter is of considerable important as it has wide application to various branches of the basic and applied science. The study will enable one to probe the validity of existing theories on stellar formation and evolution, compressibility of inertial fusion targets and check the correctness of existing models for strongly coupled high density plasma[1;2].展开更多
In the applications of primary spectrum pyrometry,based on the dynamic range and the minimum sensibility of the sensor,the application issues,such as the measurement range and the measurement partition,were investigat...In the applications of primary spectrum pyrometry,based on the dynamic range and the minimum sensibility of the sensor,the application issues,such as the measurement range and the measurement partition,were investigated through theoretical analyses. For a developed primary spectrum pyrometer,the theoretical predictions of measurement range and the distributions of measurement partition were presented through numerical simulations. And the measurement experiments of high-temperature blackbody and standard temperature lamp were processed to further verify the above theoretical analyses and numerical results. Therefore the research in the paper provides the helpful supports for the applications of primary spectrum pyrometer and other radiation pyrometers.展开更多
The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the...The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.展开更多
Although the streaked optical pyrometer(SOP)system has been widely adopted in shock temperature measurements,its reliability has always been of concern.Here,two calibrated Planckian radiators with different color temp...Although the streaked optical pyrometer(SOP)system has been widely adopted in shock temperature measurements,its reliability has always been of concern.Here,two calibrated Planckian radiators with different color temperatures were used to calibrate and verify the SOP system by comparing the two calibration standards using both multi-channel and single-channel methods.A high-color-temperature standard lamp and a multi-channel filter were specifically designed for the measurement system.To verify the reliability of the SOP system,the relative deviation between the measured data and the standard value of less than 5%was calibrated out,which demonstrates the reliability of the SOP system.Furthermore,a method to analyze the uncertainty and sensitivity of the SOP system is proposed.A series of laserinduced shock experiments were conducted at the‘Shenguang-Ⅱ’laser facility to verify the reliability of the SOP system for temperature measurements at tens of thousands of kelvin.The measured temperature of the quartz in our experiments agreed fairly well with previous works,which serves as evidence for the reliability of the SOP system.展开更多
The velocity interferometer system for any reflector(VISAR) coupled with a streaked optical pyrometer(SOP) system is used as a diagnostic tool in inertial confinement fusion(ICF) experiments involving equations of sta...The velocity interferometer system for any reflector(VISAR) coupled with a streaked optical pyrometer(SOP) system is used as a diagnostic tool in inertial confinement fusion(ICF) experiments involving equations of state and shock timing.To validate the process of adiabatically compressing the fuel shell through precise tuning of shocks in experimental campaigns for the double-cone ignition(DCI) scheme of ICF, a compact line-imaging VISAR with an SOP system is designed and implemented at the Shenguang-II upgrade laser facility. The temporal and spatial resolutions of the system are better than 30 ps and 7 μm, respectively. An illumination lens is used to adjust the lighting spot size matching with the target size. A polarization beam splitter and λ/4 waveplate are used to increase the transmission efficiency of our system. The VISAR and SOP work at 660 and 450 nm, respectively, to differentiate the signals from the scattered lights of the drive lasers. The VISAR can measure the shock velocity. At the same time, the SOP system can give the shock timing and relative strength. This system has been used in different DCI campaigns, where the generation and propagation processes of multi-shock are carefully diagnosed.展开更多
In order to study the light flash radiant intensity produced by strong shock on a 2A12 aluminum target at the same projectile incidence angles and different shock velocities,experimental measurements were conducted fo...In order to study the light flash radiant intensity produced by strong shock on a 2A12 aluminum target at the same projectile incidence angles and different shock velocities,experimental measurements were conducted for light flash phenomena of a 2A12 aluminum projectile impacting a 2A12 aluminum target under the conditions of different impact velocity and the same projectile incidence angles of 45° by using an optical pyrometer measurement system and a two-stage light gas gun loading system.Experimental results show that the peak values of the light flash radiant intensity for the wavelength of 550 nm are largest in the wavelength ranges of 600 nm,650 nm and 700 nm when a 2A12 aluminum projectile impacts a double-layer 2A12 aluminum plate in the present experimental conditions.展开更多
Great efforts are still put into the design process of advanced film-cooling configurations.In particular,the vanes and blades of turbine front stages have to be cooled extensively for a safe operation.The conjugate c...Great efforts are still put into the design process of advanced film-cooling configurations.In particular,the vanes and blades of turbine front stages have to be cooled extensively for a safe operation.The conjugate calculation technique is used for the three dimensional thermal load prediction of a fim-cooled test blade of a modern gas turbine.Thus,it becomes possible to take into account the interaction of internal flows,external flow,and heat transfer without the prescription of heat transfer ooefficients.The focus of the investigation is laid on the leading edge part of the blade.The numerical model consists of all internal flow passages and cooling hole rows at the leading edge.Furthermore,the radial gap flow is also part of the model.The comparison with thermal pyrometer measurements shows that with respect to regions with high thermal load a qualitatively and quantitatively good agreement of the conjugate results and the measurements can be found.In particular,the region in the vicinity of the mid-span section is exposed to a higher thermal load,which requires further improvement of the cooling arrangement.Altogether the achieved results demonstrate that the conjugate calculation technique is applicable for reasonable prediction of three-dimensional thermal load of complex cooling configurations for blades.展开更多
A new technique is developed to measure the longitudinal thermal expansion coefficient of C/C composite material at high temperature. The measuring principle and components of the apparatus are described in detail. Th...A new technique is developed to measure the longitudinal thermal expansion coefficient of C/C composite material at high temperature. The measuring principle and components of the apparatus are described in detail. The calculation method is derived from the temperature dependence of the thermal expansion coefficient. The apparatus mainly consists of a high temperature environmental chamber, a power circuit of heating, two high-speed pyrometers, and a laser scanning system. A long solid specimen is resistively heated to a steady high-temperature state by a steady electrical current. The temperature profile of the specimen surface is not uniform because of the thermal conduction and radiation. The temperature profile and the total expansion are measured with a high-speed scanning pyrometer and a laser slit scanning measuring system, respectively. The thermal expansion coefficient in a wide temperature range (1000 - 3800 K) of the specimen can therefore be obtained. The perfect consistency between the present and previous results justifies the validity of this technique.展开更多
The channel output of a multi-wavelength pyrometer is the brightness temperature rather than the true temperature. Twice recognition method is put forward to change the brightness temperatures of a multiwavelength pyr...The channel output of a multi-wavelength pyrometer is the brightness temperature rather than the true temperature. Twice recognition method is put forward to change the brightness temperatures of a multiwavelength pyrometer into the true temperatures of targets. Using the data offered by Dr. F. Righini, the experimental results show that the difference between the calculated true temperature based on twice recognition method and the real true temperature is within ±20 K. The method presented in this paper is feasible and effective for the true temperature measurement of targets.展开更多
A new technique is developed to measure the electrical resistivity of conductor with a nonuniform tem- perature profile. The calculation method is derived from the temperature dependence of the electrical resistivity....A new technique is developed to measure the electrical resistivity of conductor with a nonuniform tem- perature profile. The calculation method is derived from the temperature dependence of the electrical resistivity. The apparatus consists mainly of a high temperature environmental chamber, a power circuit of heating, a twenty-wavelength pyrometer, and a scanning pyrometer. After getting the resistance from the voltage drop of the specimen, the electrical resistivity in a wide temperature range of the specimen can be obtained by our calculation model. Preliminary results of the electrical resistivity of SRM 8424 over a wide temperature range (1000-3000 K) are presented. The perfect consistency between the measurement results and the nominal values justifies the validity of this technique.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.62205280)the Graduate Innovation Foundation of Yantai University(Grant No.GGIFYTU2348).
文摘Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order calculus has the inherent advantage of easily jumping out of local extreme values;here,it is introduced into the particle-swarm algorithm to invert the true temperature.An improved adaptive-adjustment mechanism is applied to automatically adjust the current velocity order of the particles and update their velocity and position values,increasing the accuracy of the true temperature values.The results of simulations using the proposed algorithm were compared with three algorithms using typical emissivity models:the internal penalty function algorithm,the optimization function(fmincon)algorithm,and the conventional particle-swarm optimization algorithm.The results show that the proposed algorithm has good accuracy for true-temperature inversion.Actual experimental results from a rocket-motor plume were used to demonstrate that the true-temperature inversion results of this algorithm are in good agreement with the theoretical true-temperature values.
文摘In general, the dependence of the logarithm of the emissivity upon wavelength is usually used in the treatment of data measured by multi-wavelength pyrometer. In this paper, the suitability of this expression for different materials has been examined. Further more, an effective method for automatically searching the mathematical model between emissivity and wavelength has been procsed. The calculated results show that the accuracy is improved by using this data treatment method.
基金Jilin Province Science and Technology Development Plan Project(20190701024GH)。
文摘The measurement and control of high temperature play very important roles in national defense,military,scientific experiments,industrial and agricultural production.Photoelectric pyrometer is one of the important radiation thermometers for non-contact temperature measurement.It has an important application in the field of high temperature measurement,and its performance directly affects the accuracy of temperature measurement.By improving the design of the detection optical system of the photoelectric pyrometer,the imaging performance of the photoelectric pyrometer can be improved effectively,and the temperature measurement accuracy can be improved.In this paper,the temperature measurement principle of photoelectric pyrometer,the wo rking principle of the detection optical system and the composition of the system are introduced.The optical components that affect the imaging of the optical system of the photoelectric pyrometer are analyzed.The optical pyrometer detection optical system is simulated by ZEMAX software,based on the analysis results,the Modulation Transfer Function(MTF)and the spot Diagram are used as the main evaluation criteria to optimize the design of the objective lens of the photoelectric pyrometer detection optical system.The imaging performance of the photoelectric pyrometer detection optical system and the accuracy of temperature measurement of the photoelectric pyrometer are improved by optimization design of the detection optical system.
基金supported by the National Natural Science Foundation of China(No.11972046)Outstanding Youth Project of Natural Science Foundation of Anhui Province(No.2108085Y02)+1 种基金Major Project of Anhui University Natural Science Foundation(No.KJ2020ZD30)Anhui University of Science and Technology Postgraduate Innovation Fund(No.2020CX2066)。
文摘In the study,the two-color pyrometer technique was used to measure the transient temperature field of emulsion explosives with different contents of TiH_(2)powders.The experimental results showed that the introduction of TiH_(2)powders could significantly increase the explosion temperature and fireball duration of emulsion explosive.When emulsion explosives were ignited,the average explosion temperature of pure emulsion explosive continuously decreased while emulsion explosives added with TiH_(2)powders increased at first and then decreased.When the content of TiH_(2)powders was 6 mass%,the explosion average temperature reached its maximum value of 3095 K,increasing by 43.7%as compared with that of pure emulsion explosive.In addition,the results of air blast experiment and explosion heat test showed that the variation trends of shock wave parameters,explosion heat and theoretical explosion temperature of emulsion explosives with different contents of TiH_(2)powders were basically consistent with that of explosion temperature measured by the two-color pyrometer technique.In conclusion,the two-color pyrometer technique would be conducive to the formula design of emulsion explosive by understanding the explosion temperature characteristics.
基金Sponsored by the National Natural Science Foundation of China (10772032)
文摘An infrared colorimetric radiation thermometrical system was established based on the theory of optical radiation. The dynamic temperature history of fuel air explosive (FAE) was measured to obtain the temperature responses of primary initiation FAE and secondary initiation FAE in real time. And the characteristics of their temperature history curves were compared and analyzed. The results show that the primary initiation FAE has higher explosion temperature and longer duration compared to the secondary initiation FAE.
基金supported by National Natural Science Foundation of China(Nos.11005097 and 1175179)the Innovation Project of the Chinese Academy of Sciences(No.KJCX2-YW-N36)the Project 2010A0102003 supported by CAEP
文摘A streaked optical pyrometer (SOP) is developed and calibrated for the measurement of the temperature of shocked materials. In order to achieve a higher relative sensitivity, a onechannel scheme is adopted for the system. The system is calibrated with a shocked step-shaped aluminum sample in the SG-III prototype laser facility. The relation between the count number in the detection system and the sample temperature is thus obtained, which can be adopted to infer the temperature of any shocked materials in future experiments.
文摘In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algorithm based on the methods of synchronous detection providing
文摘A study of the fundamental properties of high-energy-density (HED) matter is of considerable important as it has wide application to various branches of the basic and applied science. The study will enable one to probe the validity of existing theories on stellar formation and evolution, compressibility of inertial fusion targets and check the correctness of existing models for strongly coupled high density plasma[1;2].
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50606033 and 50674079)
文摘In the applications of primary spectrum pyrometry,based on the dynamic range and the minimum sensibility of the sensor,the application issues,such as the measurement range and the measurement partition,were investigated through theoretical analyses. For a developed primary spectrum pyrometer,the theoretical predictions of measurement range and the distributions of measurement partition were presented through numerical simulations. And the measurement experiments of high-temperature blackbody and standard temperature lamp were processed to further verify the above theoretical analyses and numerical results. Therefore the research in the paper provides the helpful supports for the applications of primary spectrum pyrometer and other radiation pyrometers.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272001,11972046)the Outstanding Youth Project of Natural Science Foundation of Anhui Province(Grant No.2108085Y02)the Major Project of Anhui University Natural Science Foundation(Grant No.KJ2020ZD30)。
文摘The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.
基金supported by the National Key R&D Program of China (No. 2017YFA0403200)the Science Challenge Project (No. TZ2016001)
文摘Although the streaked optical pyrometer(SOP)system has been widely adopted in shock temperature measurements,its reliability has always been of concern.Here,two calibrated Planckian radiators with different color temperatures were used to calibrate and verify the SOP system by comparing the two calibration standards using both multi-channel and single-channel methods.A high-color-temperature standard lamp and a multi-channel filter were specifically designed for the measurement system.To verify the reliability of the SOP system,the relative deviation between the measured data and the standard value of less than 5%was calibrated out,which demonstrates the reliability of the SOP system.Furthermore,a method to analyze the uncertainty and sensitivity of the SOP system is proposed.A series of laserinduced shock experiments were conducted at the‘Shenguang-Ⅱ’laser facility to verify the reliability of the SOP system for temperature measurements at tens of thousands of kelvin.The measured temperature of the quartz in our experiments agreed fairly well with previous works,which serves as evidence for the reliability of the SOP system.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA25030500 and XDA25010300)the CAS Youth Interdisciplinary Team(Grant No.JCTD-2022-05)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe National Natural Science Foundation of China(Grant Nos.11873061 and 12073043)the National Key R&D Program of China(Grant Nos.2022YFA1603200 and 2022YFA1603204)。
文摘The velocity interferometer system for any reflector(VISAR) coupled with a streaked optical pyrometer(SOP) system is used as a diagnostic tool in inertial confinement fusion(ICF) experiments involving equations of state and shock timing.To validate the process of adiabatically compressing the fuel shell through precise tuning of shocks in experimental campaigns for the double-cone ignition(DCI) scheme of ICF, a compact line-imaging VISAR with an SOP system is designed and implemented at the Shenguang-II upgrade laser facility. The temporal and spatial resolutions of the system are better than 30 ps and 7 μm, respectively. An illumination lens is used to adjust the lighting spot size matching with the target size. A polarization beam splitter and λ/4 waveplate are used to increase the transmission efficiency of our system. The VISAR and SOP work at 660 and 450 nm, respectively, to differentiate the signals from the scattered lights of the drive lasers. The VISAR can measure the shock velocity. At the same time, the SOP system can give the shock timing and relative strength. This system has been used in different DCI campaigns, where the generation and propagation processes of multi-shock are carefully diagnosed.
基金supported by National Natural Science Foundation of China(Nos.10972145,11272218,11472178)State Key Program of National Natural Science of China(No.11032003)Program for Liaoning Excellent Talents in University,China(No.LR2013008)
文摘In order to study the light flash radiant intensity produced by strong shock on a 2A12 aluminum target at the same projectile incidence angles and different shock velocities,experimental measurements were conducted for light flash phenomena of a 2A12 aluminum projectile impacting a 2A12 aluminum target under the conditions of different impact velocity and the same projectile incidence angles of 45° by using an optical pyrometer measurement system and a two-stage light gas gun loading system.Experimental results show that the peak values of the light flash radiant intensity for the wavelength of 550 nm are largest in the wavelength ranges of 600 nm,650 nm and 700 nm when a 2A12 aluminum projectile impacts a double-layer 2A12 aluminum plate in the present experimental conditions.
文摘Great efforts are still put into the design process of advanced film-cooling configurations.In particular,the vanes and blades of turbine front stages have to be cooled extensively for a safe operation.The conjugate calculation technique is used for the three dimensional thermal load prediction of a fim-cooled test blade of a modern gas turbine.Thus,it becomes possible to take into account the interaction of internal flows,external flow,and heat transfer without the prescription of heat transfer ooefficients.The focus of the investigation is laid on the leading edge part of the blade.The numerical model consists of all internal flow passages and cooling hole rows at the leading edge.Furthermore,the radial gap flow is also part of the model.The comparison with thermal pyrometer measurements shows that with respect to regions with high thermal load a qualitatively and quantitatively good agreement of the conjugate results and the measurements can be found.In particular,the region in the vicinity of the mid-span section is exposed to a higher thermal load,which requires further improvement of the cooling arrangement.Altogether the achieved results demonstrate that the conjugate calculation technique is applicable for reasonable prediction of three-dimensional thermal load of complex cooling configurations for blades.
基金General Armament Department under Grant No.51312060201.
文摘A new technique is developed to measure the longitudinal thermal expansion coefficient of C/C composite material at high temperature. The measuring principle and components of the apparatus are described in detail. The calculation method is derived from the temperature dependence of the thermal expansion coefficient. The apparatus mainly consists of a high temperature environmental chamber, a power circuit of heating, two high-speed pyrometers, and a laser scanning system. A long solid specimen is resistively heated to a steady high-temperature state by a steady electrical current. The temperature profile of the specimen surface is not uniform because of the thermal conduction and radiation. The temperature profile and the total expansion are measured with a high-speed scanning pyrometer and a laser slit scanning measuring system, respectively. The thermal expansion coefficient in a wide temperature range (1000 - 3800 K) of the specimen can therefore be obtained. The perfect consistency between the present and previous results justifies the validity of this technique.
基金This work was supported by the National Natural Science Foundation of China under Grant No.60377037.
文摘The channel output of a multi-wavelength pyrometer is the brightness temperature rather than the true temperature. Twice recognition method is put forward to change the brightness temperatures of a multiwavelength pyrometer into the true temperatures of targets. Using the data offered by Dr. F. Righini, the experimental results show that the difference between the calculated true temperature based on twice recognition method and the real true temperature is within ±20 K. The method presented in this paper is feasible and effective for the true temperature measurement of targets.
基金supported by the General Armament Department under Grant No. 51312060201
文摘A new technique is developed to measure the electrical resistivity of conductor with a nonuniform tem- perature profile. The calculation method is derived from the temperature dependence of the electrical resistivity. The apparatus consists mainly of a high temperature environmental chamber, a power circuit of heating, a twenty-wavelength pyrometer, and a scanning pyrometer. After getting the resistance from the voltage drop of the specimen, the electrical resistivity in a wide temperature range of the specimen can be obtained by our calculation model. Preliminary results of the electrical resistivity of SRM 8424 over a wide temperature range (1000-3000 K) are presented. The perfect consistency between the measurement results and the nominal values justifies the validity of this technique.