The solar temperature field of a large three-span continuous bridge with steel-concrete composite box girder and variable cross-section is measured to verify a calculation method for the temperature field of steel-con...The solar temperature field of a large three-span continuous bridge with steel-concrete composite box girder and variable cross-section is measured to verify a calculation method for the temperature field of steel-concrete composite beams. The test results show that the temperature of an external steel web- plate is higher than that of an internal web-plate due to the difference in solar radiation. Air temperature inside the box matches the average temperature of the whole steel box. Based on actual measurements, a transient thermal analysis with multiple boundary conditions is also carried out by a software program ANSYS. Convective boundary situation and states of solar radiation on steel web plates in different situations are determined in the analysis. The feature of the temperature field is preliminarily achieved through a comparative study between the actual measurement and the finite element analysis. The computed results are in good consistence with the actual measurement results, with the maximum difference within 2 ℃. This indicates that the theoretical calculation method is reliable and it provides a foundation for further research on temperature field distribution in the steel-concrete composite box girder.展开更多
In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared vi...In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared video signals obtained by the experiment are processed with SAT.Then the infrared radiation signals are processed by EMD with Hilbert–Huang and the infrared radiation noise is effectively removed.The research results show that the desorption process,with the change of the temperature,is an endothermic process.The coal absorbs heat when the gas is desorbed and the temperature drops.The coal body temperature drop range is obviously related to coal particle size.The smaller the particle size is,the bigger the temperature drop becomes.The temperature variation curves in the process of coal gas desorption under different particle sizes are fitted,and they comply with the exponential function.The research results lay the theoretical and experimental foundation for non-contact prediction on working face of coal and gas outburst with infrared thermal image technology.展开更多
文摘The solar temperature field of a large three-span continuous bridge with steel-concrete composite box girder and variable cross-section is measured to verify a calculation method for the temperature field of steel-concrete composite beams. The test results show that the temperature of an external steel web- plate is higher than that of an internal web-plate due to the difference in solar radiation. Air temperature inside the box matches the average temperature of the whole steel box. Based on actual measurements, a transient thermal analysis with multiple boundary conditions is also carried out by a software program ANSYS. Convective boundary situation and states of solar radiation on steel web plates in different situations are determined in the analysis. The feature of the temperature field is preliminarily achieved through a comparative study between the actual measurement and the finite element analysis. The computed results are in good consistence with the actual measurement results, with the maximum difference within 2 ℃. This indicates that the theoretical calculation method is reliable and it provides a foundation for further research on temperature field distribution in the steel-concrete composite box girder.
基金provided by the National Natural Science Foundation of China (No.51174157)the Doctor Start-up Fund of Xi’an University of Science and Technology of China (No.2013QDJ005)the Research Development Fund of Xi’an University of Science and Technology of China (No.201244)
文摘In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared video signals obtained by the experiment are processed with SAT.Then the infrared radiation signals are processed by EMD with Hilbert–Huang and the infrared radiation noise is effectively removed.The research results show that the desorption process,with the change of the temperature,is an endothermic process.The coal absorbs heat when the gas is desorbed and the temperature drops.The coal body temperature drop range is obviously related to coal particle size.The smaller the particle size is,the bigger the temperature drop becomes.The temperature variation curves in the process of coal gas desorption under different particle sizes are fitted,and they comply with the exponential function.The research results lay the theoretical and experimental foundation for non-contact prediction on working face of coal and gas outburst with infrared thermal image technology.
