Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal...Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal at low temperatures.Using this method, we calculated the oxidative heat release intensity of differently sized loose coals by comparing the temperature rise of the coal in nitrogen or an air environment.The results show that oxidation heat release intensity of Shenhua coal sized 0～15 mm is 0.001～0.03 W/m3 at 30～90 °C and increases with increasing temperature.The heat release intensity at a given temperature is larger for smaller sized coal.The temperature effect on heat release intensity is muted as the coal size increases.At lower temperature the change in heat release intensity as a function of size becomes smaller.These results show that the test system is usable for practical applications and is easy to operate and is capable of measuring mass samples.展开更多
We present a new calorimetric method for measuring alternative current(AC)losses of high-temperature superconducting(HTS)tapes by optical fiber Bragg grating(FBG),which is particularly well suited for the AC loss meas...We present a new calorimetric method for measuring alternative current(AC)losses of high-temperature superconducting(HTS)tapes by optical fiber Bragg grating(FBG),which is particularly well suited for the AC loss measurement of Re BCO wires,so-called the second generation(2G)HTS wires.Compared with conventional calorimetric methods,the suggested method is both free of electromagnetic disturbance,magnetic field,and fast as well as simple.Self-field AC losses are measured by the optical FBG method and the conventional lock-in-amplifier(LIA)technique,respectively.The results show that the measured AC loss is in good agreement with those measured by the electric method,thus the presented calorimetric method would be available for measuring the AC loss of 2G wire and is expected to be generalized for the measurement of AC loss or thermal performances of HTS bulk.展开更多
基金Projects 50474067 supported by the National Natural Science Foundation of China2007KF11 by the State Key Laboratory of Coal Resources and Safety Mining
文摘Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal at low temperatures.Using this method, we calculated the oxidative heat release intensity of differently sized loose coals by comparing the temperature rise of the coal in nitrogen or an air environment.The results show that oxidation heat release intensity of Shenhua coal sized 0～15 mm is 0.001～0.03 W/m3 at 30～90 °C and increases with increasing temperature.The heat release intensity at a given temperature is larger for smaller sized coal.The temperature effect on heat release intensity is muted as the coal size increases.At lower temperature the change in heat release intensity as a function of size becomes smaller.These results show that the test system is usable for practical applications and is easy to operate and is capable of measuring mass samples.
基金supported by the National Natural Science Foundation of China(Grant No.51477053)the Beijing Education Commissions(Grant No.GJ2013009)
文摘We present a new calorimetric method for measuring alternative current(AC)losses of high-temperature superconducting(HTS)tapes by optical fiber Bragg grating(FBG),which is particularly well suited for the AC loss measurement of Re BCO wires,so-called the second generation(2G)HTS wires.Compared with conventional calorimetric methods,the suggested method is both free of electromagnetic disturbance,magnetic field,and fast as well as simple.Self-field AC losses are measured by the optical FBG method and the conventional lock-in-amplifier(LIA)technique,respectively.The results show that the measured AC loss is in good agreement with those measured by the electric method,thus the presented calorimetric method would be available for measuring the AC loss of 2G wire and is expected to be generalized for the measurement of AC loss or thermal performances of HTS bulk.
