The theoretical characterizations on the triangular-form thixotropy-loop tests of an LDPE melt （PE-FSB- 23D022/Q200） were conducted in the present paper by using a new thixotropy model, which is constituted by the u...The theoretical characterizations on the triangular-form thixotropy-loop tests of an LDPE melt （PE-FSB- 23D022/Q200） were conducted in the present paper by using a new thixotropy model, which is constituted by the upper convected Maxwell model and a rate-type kinetic equation. The new thixotropic Maxwell model can partially describe well three reported thixotropy-loop experiments by comparison with the previous calculations of the variant form of the thixotropy-type Huang model. It is noted that the stress deviations between the experiments and the predictions of the new thixotropic Maxwell model are much slighter than those deviations obtained by using the variant Huang model at the same condition, although both models include five parameters. The constitution of the new thixotropic Maxwell model is more reasonable than that of the variant Huang model.展开更多
A High Temperature Gas Cooled Reactor （HTGR） with an outlet coolant temperature of 950 ℃ is considered as an efficient reactor to couple with the thermo-chemical Sulfur Iodine （SI） cycle for a hydrogen production...A High Temperature Gas Cooled Reactor （HTGR） with an outlet coolant temperature of 950 ℃ is considered as an efficient reactor to couple with the thermo-chemical Sulfur Iodine （SI） cycle for a hydrogen production. The test loop was installed in the Korea Atomic Energy Research Institute （KAERI） facility to confirm the integrity of the sulfur trioxide decomposer, one of the key components in the test loop, under HTGR operating conditions. In this paper, the simulation using Aspen plus, a chemical process simulator, was made to evaluate the performance of a sulfur trioxide decomposer. The simulation indicated that at least 10 kW heat needs to be supplied to the sulfur trioxide decomposer in the test loop when the sulfuric acid flowrate is 0.5 kg/min. The simulation flowsheet was obtained and the material balance around the sulfur trioxide decomposer was determined in case of 10 kW heat input and 0.5 kg/min flowrate of liquid sulfuric acid. The parametric study was carried out for sulfur trioxide decomposer. It indicated that the moles of sulfur dioxide produced at the decomposer increases as the operating temperature increases and is decreasing as the operating pressure becomes higher at a given temperature. The parametric study also indicated water vapor removal out of the decomposer is a less effective method to increase the sulfur trioxide conversion ratio.展开更多
The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing appro...The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing approach. It is found the variation of ramp amplitude will lead to the alternation of gyro bias. The amplitude and the phase parameters of the electrical crosstalk signal are measured by lock-in amplifier, and the variation of gyro bias is confirmed to be caused by the alternation of phase according to the amplitude of the ramp. A digital closed-loop fibre optic gyro electrical crosstalk-coupling model is built by approximating the electrical cross-coupling paths as a proportion and integration segment. The results of simulation and experiment show that the modulation signal electrical crosstalk-coupling can cause the dead zone of the gyro when a small angular velocity is inputted, and it could also lead to a periodic vibration of the bias error of the gyro when a large angular velocity is inputted.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No. 10402024).
文摘The theoretical characterizations on the triangular-form thixotropy-loop tests of an LDPE melt （PE-FSB- 23D022/Q200） were conducted in the present paper by using a new thixotropy model, which is constituted by the upper convected Maxwell model and a rate-type kinetic equation. The new thixotropic Maxwell model can partially describe well three reported thixotropy-loop experiments by comparison with the previous calculations of the variant form of the thixotropy-type Huang model. It is noted that the stress deviations between the experiments and the predictions of the new thixotropic Maxwell model are much slighter than those deviations obtained by using the variant Huang model at the same condition, although both models include five parameters. The constitution of the new thixotropic Maxwell model is more reasonable than that of the variant Huang model.
文摘A High Temperature Gas Cooled Reactor （HTGR） with an outlet coolant temperature of 950 ℃ is considered as an efficient reactor to couple with the thermo-chemical Sulfur Iodine （SI） cycle for a hydrogen production. The test loop was installed in the Korea Atomic Energy Research Institute （KAERI） facility to confirm the integrity of the sulfur trioxide decomposer, one of the key components in the test loop, under HTGR operating conditions. In this paper, the simulation using Aspen plus, a chemical process simulator, was made to evaluate the performance of a sulfur trioxide decomposer. The simulation indicated that at least 10 kW heat needs to be supplied to the sulfur trioxide decomposer in the test loop when the sulfuric acid flowrate is 0.5 kg/min. The simulation flowsheet was obtained and the material balance around the sulfur trioxide decomposer was determined in case of 10 kW heat input and 0.5 kg/min flowrate of liquid sulfuric acid. The parametric study was carried out for sulfur trioxide decomposer. It indicated that the moles of sulfur dioxide produced at the decomposer increases as the operating temperature increases and is decreasing as the operating pressure becomes higher at a given temperature. The parametric study also indicated water vapor removal out of the decomposer is a less effective method to increase the sulfur trioxide conversion ratio.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2007AA04Z436)
文摘The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing approach. It is found the variation of ramp amplitude will lead to the alternation of gyro bias. The amplitude and the phase parameters of the electrical crosstalk signal are measured by lock-in amplifier, and the variation of gyro bias is confirmed to be caused by the alternation of phase according to the amplitude of the ramp. A digital closed-loop fibre optic gyro electrical crosstalk-coupling model is built by approximating the electrical cross-coupling paths as a proportion and integration segment. The results of simulation and experiment show that the modulation signal electrical crosstalk-coupling can cause the dead zone of the gyro when a small angular velocity is inputted, and it could also lead to a periodic vibration of the bias error of the gyro when a large angular velocity is inputted.
