According to the formation of shock wave resulting from coal and gas outburst, the gas flow of coal and gas outburst was transformed from an unsteady flow to a steady one based on selected appropriate reference coordi...According to the formation of shock wave resulting from coal and gas outburst, the gas flow of coal and gas outburst was transformed from an unsteady flow to a steady one based on selected appropriate reference coordinates, and the mathematical expressions were then established by applying mass conservation, momentum conservation equation, and energy conservation equation. On this basis, analyzed gas flow mitigation of variable cross-section area and the outburst intensity, and the relations between cross-section area, velocity, and density; the relations between overpressures and outburst intensity were deduced. Furthermore, shock waves resulting from coal and gas outburst and outburst intensity were measured by experimental setup, the overpressure and outburst intensity of different gas pressures were obtained, and the similar conditions of the experiment were numerically simulated. The averaged overpressure and gas flow velocity of variable cross-section under different gas pressures were numerically derived. The results show that the averaged overpressure and outburst intensity obtained from simulation are in good agreement with the experimental results. Moreover, the gas flow velocity of variable cross-sections approximates to the theoretical analysis.展开更多
The pure thermal spectrum in dragging coordinate system and the tunneling radiation characteristics across the event horizon for stationary Demianski-Newman black hole are researched. The result shows that the tunneli...The pure thermal spectrum in dragging coordinate system and the tunneling radiation characteristics across the event horizon for stationary Demianski-Newman black hole are researched. The result shows that the tunneling rate of the particle is relevant to Bekenstein-Hawking entropy, and the derived radiate spectrum is not strictly pure thermal, but is consistent with underlying unitary theory. Finally, we use the obtained results to reduce to stationary Kerr black hole and static Schwarzschild black hole, and lind that only when ignoring the spectrum at higher energies is the tunneling radiation spectrum consistent with Hawking pure thermal one.展开更多
In this paper, a novel unsteady fluid network simulation method to compute the air system of jet engine was coded to predict the characteristics of pressure, temperature and mass flow rate of the flow and the temperat...In this paper, a novel unsteady fluid network simulation method to compute the air system of jet engine was coded to predict the characteristics of pressure, temperature and mass flow rate of the flow and the temperature of the solid in the gas turbine engine. The fluid and solid areas are divided into the network comprised of branches and nodes, and the method solves transient mass, energy conservation equations at each node and momentum conservation equation at each branch by a newly deduced numerical method. With this method, to simulate complicated fluid and solid system in short time becomes possible. To verify the code developed, it has been applied to simulate a gas turbine model against the widely used commercial software Flowmaster. And the comparisons show that the two are in good agreement. Then the verified program is applied to the prediction of the characteristics of a designed turbine disk and air-cooling system associated to it, and useful information is obtained.展开更多
基金Supported by the National Natural Science Foundation of China （50874111） the National High Technology Research and Development Program （2009AA063201）+2 种基金 the Program for New Century Excellent Talents in University of China （NCET-10-0724） the Fundamental Research Funds for Central Universities（2010QZ05） SRF for ROCS, SEM
文摘According to the formation of shock wave resulting from coal and gas outburst, the gas flow of coal and gas outburst was transformed from an unsteady flow to a steady one based on selected appropriate reference coordinates, and the mathematical expressions were then established by applying mass conservation, momentum conservation equation, and energy conservation equation. On this basis, analyzed gas flow mitigation of variable cross-section area and the outburst intensity, and the relations between cross-section area, velocity, and density; the relations between overpressures and outburst intensity were deduced. Furthermore, shock waves resulting from coal and gas outburst and outburst intensity were measured by experimental setup, the overpressure and outburst intensity of different gas pressures were obtained, and the similar conditions of the experiment were numerically simulated. The averaged overpressure and gas flow velocity of variable cross-section under different gas pressures were numerically derived. The results show that the averaged overpressure and outburst intensity obtained from simulation are in good agreement with the experimental results. Moreover, the gas flow velocity of variable cross-sections approximates to the theoretical analysis.
基金The project supported by National Natural Science Foundation of China under Grant No. 10347008 and the Science Foundation for Fundamental Research of Sichuan Province of China under Grant No. 05JY029-092 Great thanks are due to Prof. Zhang Jing-Yi and Dr. Ren Jun for their helpful discussion.
文摘The pure thermal spectrum in dragging coordinate system and the tunneling radiation characteristics across the event horizon for stationary Demianski-Newman black hole are researched. The result shows that the tunneling rate of the particle is relevant to Bekenstein-Hawking entropy, and the derived radiate spectrum is not strictly pure thermal, but is consistent with underlying unitary theory. Finally, we use the obtained results to reduce to stationary Kerr black hole and static Schwarzschild black hole, and lind that only when ignoring the spectrum at higher energies is the tunneling radiation spectrum consistent with Hawking pure thermal one.
文摘In this paper, a novel unsteady fluid network simulation method to compute the air system of jet engine was coded to predict the characteristics of pressure, temperature and mass flow rate of the flow and the temperature of the solid in the gas turbine engine. The fluid and solid areas are divided into the network comprised of branches and nodes, and the method solves transient mass, energy conservation equations at each node and momentum conservation equation at each branch by a newly deduced numerical method. With this method, to simulate complicated fluid and solid system in short time becomes possible. To verify the code developed, it has been applied to simulate a gas turbine model against the widely used commercial software Flowmaster. And the comparisons show that the two are in good agreement. Then the verified program is applied to the prediction of the characteristics of a designed turbine disk and air-cooling system associated to it, and useful information is obtained.
