| With the rapid development of social economy, the ETT( evacuated tube transport) system will certainly become an important transport vehicle in the future. And how to reduce the ETT system construction costs, operating costs and improve system economic speed is one of the key factors to the successful construction of the evacuated tube transport system. Therefore, the study of the operation energy consumption problem of the ETT system is imminent.This paper tacking three parameters of the blocking ratio, train running speed and internal tube pressure, using the finite volume method, according to the mechanism of the train runs in the evacuated tube, establish physical and mathematical models of the running train under the thermal-pressure coupling effect, the flow field characteristics of the system is detailed analyzed, the results showed that:(1)The differential pressure of the train increases with the train running speed, blocking ratio, pressure system increasing, leading to aerodynamic drag of the train increases.(2)When the blocking ratios is constants, as the system pressure decreases, and when the train running speed improving, the differential pressure resistance maintains the constant, namely in the ETT system, reducing the system pressure, when the system overcoming the pressure drag loss under the condition of equal energy, this can make the train stay at the high-speed running state, to achieve the goal of low energy consumption and high speed.Numerical simulation is used, when the train speed is changing from 100 m to 400 m/s to system pressure decreasing from 1 atm to 0.05 atm, blocking ratio respectively at 0.18, 0.23, 0.32, 0.46, the differential pressure of the running train and relative speed trains with the surrounding gas are calculated, the aerodynamic drag of the system is analyzed, and, change law of ETT system operation energy consumption changing with the parameters is observed at different working conditions.(1)When the system pressure is constants, as the train speed increases, the train traction energy consumption is parabolic growth trend, and maintaining the vacuum of energy decreases; on the other hand, as the blocking ratio increases, the train traction energy consumption by aerodynamic drag increases, but maintaining the vacuum of energy decreases. As the train speed increases, the total operation energy consumption decreases first and then increases, the total operation energy consumption reaches the minimum value; and when the system blocking ratio increases, resulting in that the speed decreasing when the total energy consumption reaching minimum, as the train speed increases the total energy consumption is rapidly improved.(2)When the blocking ratio is constants, as the system pressure increases the train traction energy consumption will maintain the linear growth trend, maintaining the vacuum of energy parabolic downward trend; At the same time, the faster the train runs, the more track traction energy it takes and the less energy consumption to maintain the system vacuum. When the train speed is 100 m/s, as the system pressure increases, the total energy consumption presents the negative growth trend, When the train speed is about 200 m/s, total energy consumption almost keep the same as increase of the system pressure; But when the train speed is after more than 200 m/s, the total energy consumption is positively growth trend.(3)When the train speed is constants, as the blocking ratio increases, the train traction energy consumption is parabolic growth trend, but maintaining the vacuum of energy decreases, At the same time as system pressure increases, the train traction energy consumption increases, but maintaining the vacuum of energy is decrease. As the blocking ratio increases, the total energy consumption is parabolic growth trend, it reaches wave trough appear at low system pressure. And as system pressure increases, The total energy consumption curve slope show a increased trend.According to the above research conclusion, the correlations that the parameters of ETT system blockage ratio, system pressure, train speed affecting the total energy consumption is obtained. Blockage ratio, system pressure and train speed increase, the train traction energy consumption increases, but maintaining the vacuum of energy is decrease. Therefore, considering the parameters of ETT system blocking ratio, system pressure, and train speed affect the total energy consumption, in order to achieve optimum energy operating parameters.By comparing two kinds transportation ETT system and CRH 3 total energy consumption, as the train speed increases, the gap between energy consumption is growing. When the train speed is 345 km/h, at standard atmospheric pressure environment CRH 3 total energy consumption equal to 5 times higher than ETT system total energy consumption, meaning the speed of the ETT system is greater than CRH 3 with the same energy consumption. |
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