In the proposed paper, the new experimental results are described obtained from the laboratory stand and the model developed by the authors. A method of acquiring characteristics of a pump motor drive using a hardware...In the proposed paper, the new experimental results are described obtained from the laboratory stand and the model developed by the authors. A method of acquiring characteristics of a pump motor drive using a hardware-in-the-loop simulation approach is explained. To explore the centrifugal pumps manufactured by ABB, their own control system is used whereas an industrial pump is replaced with the specially designed simulator. To clarify the model topology and parameters, a double-machine assembly was designed and used as universal pump prototype. A library of reference and disturbance signals used in pumping was applied as a modeling tool. In this way, the advantages of mathematical and physical simulations have been combined with optimal interaction of both approaches.展开更多
This research proposes a new theory in the field of physics and space technology, based on several scientific hypotheses and conclusions, as it plans to manufacture a “new magnetic focus” by means of high-speed cent...This research proposes a new theory in the field of physics and space technology, based on several scientific hypotheses and conclusions, as it plans to manufacture a “new magnetic focus” by means of high-speed centrifugal engines, by equipping a group of them, and installing heavy, dense fans, not for the purpose of air pressure, Rather, it works to rotate at a speed of up to 1000 kilometers per hour at an angle of 45 degrees, and is lined up in front of each other in a circle, so that the final result is to transfer the effort and weight of the propellers to an upper point in their midst, and this point will reach a large degree of density, size and mass, causing the generation of a point independent magnetic attraction, which pulls the motors upward, as a result of the mutual gravitational effect created by the motors. These hypotheses need a large number of experiments, applications, and analyze the use of specialists in physics, technology, technology, engine engineers, and others, and the correct results will cause a major revolution in the field of space technology, and this theory will be relied upon in many means of land, air, and space transportation and different fields.展开更多
作动器系统作为直升机结构响应主动控制系统(active control of structure response, ACSR)执行元件的重要核心部件,其控制性能直接关系到振动的抑制效果。研制了一套基于永磁无刷直流电机驱动的离心式作动器原理样机,详细阐述了系统组...作动器系统作为直升机结构响应主动控制系统(active control of structure response, ACSR)执行元件的重要核心部件,其控制性能直接关系到振动的抑制效果。研制了一套基于永磁无刷直流电机驱动的离心式作动器原理样机,详细阐述了系统组成及工作原理,论述了作动器输出力频率、幅值和相位的调节方式,建立了偏心块的输出力方程,选取了MAXON公司生产的EC60 flat 411 678无刷电机作为驱动源。设计了作动器伺服控制系统,针对功率驱动中的隔离直流电源、自举二极管、自举电容、电流驱动能力及母线支撑电容等关键参数进行了详细设计。通过实验验证,电机转速误差最终被控制为1%以内,位置响应时间小于50 ms,振动抑制在0.001 5g(g为重力加速度)以下,取得了较好的控制性能,为离心式作动器系统在直升机平台的应用奠定了基础。展开更多
A new cooling technique based on thermal driving in high centrifugal field （TDHCF） is developed for gas turbine rotational components, such as turbine blades. The key point of TDHCF is to enhance heat transfer by th...A new cooling technique based on thermal driving in high centrifugal field （TDHCF） is developed for gas turbine rotational components, such as turbine blades. The key point of TDHCF is to enhance heat transfer by the fluid thermal driving in closed loop small channels placed in the high centrifugal field. Heat transfer characteristics of the new cooling technique are analyzed. In experiments, two different fluids （liquid water and Freon R12） are used as thermal driving media （fluid inside the loop channel）. And the channel width d is 1 mm and the height h is 30 mm. The temperature is measured by thermocouples and an average heat transfer coefficient KH is defined to indicate heat transfer capacity of TDHCF. Experimental results show that KH is enhanced when heat flux and the rotating speed increase. And thermal properties of thermal driving media are also influenced by KH. Larger KH can be achieved by using Freon R12 as thermal driving medium compared with using liquid water. It can increase to 2 300 W/（m^2 · K） and it is much higher than that of the normal air cooling method （usually at the level of 600-1200 W/（m^2·K））. All fundamental studies of TDHCF show that there actually exists thermal driving in the closed loop small channel in the centrifugal field to improve heat transfer characteristics.展开更多
文摘In the proposed paper, the new experimental results are described obtained from the laboratory stand and the model developed by the authors. A method of acquiring characteristics of a pump motor drive using a hardware-in-the-loop simulation approach is explained. To explore the centrifugal pumps manufactured by ABB, their own control system is used whereas an industrial pump is replaced with the specially designed simulator. To clarify the model topology and parameters, a double-machine assembly was designed and used as universal pump prototype. A library of reference and disturbance signals used in pumping was applied as a modeling tool. In this way, the advantages of mathematical and physical simulations have been combined with optimal interaction of both approaches.
文摘This research proposes a new theory in the field of physics and space technology, based on several scientific hypotheses and conclusions, as it plans to manufacture a “new magnetic focus” by means of high-speed centrifugal engines, by equipping a group of them, and installing heavy, dense fans, not for the purpose of air pressure, Rather, it works to rotate at a speed of up to 1000 kilometers per hour at an angle of 45 degrees, and is lined up in front of each other in a circle, so that the final result is to transfer the effort and weight of the propellers to an upper point in their midst, and this point will reach a large degree of density, size and mass, causing the generation of a point independent magnetic attraction, which pulls the motors upward, as a result of the mutual gravitational effect created by the motors. These hypotheses need a large number of experiments, applications, and analyze the use of specialists in physics, technology, technology, engine engineers, and others, and the correct results will cause a major revolution in the field of space technology, and this theory will be relied upon in many means of land, air, and space transportation and different fields.
文摘A new cooling technique based on thermal driving in high centrifugal field （TDHCF） is developed for gas turbine rotational components, such as turbine blades. The key point of TDHCF is to enhance heat transfer by the fluid thermal driving in closed loop small channels placed in the high centrifugal field. Heat transfer characteristics of the new cooling technique are analyzed. In experiments, two different fluids （liquid water and Freon R12） are used as thermal driving media （fluid inside the loop channel）. And the channel width d is 1 mm and the height h is 30 mm. The temperature is measured by thermocouples and an average heat transfer coefficient KH is defined to indicate heat transfer capacity of TDHCF. Experimental results show that KH is enhanced when heat flux and the rotating speed increase. And thermal properties of thermal driving media are also influenced by KH. Larger KH can be achieved by using Freon R12 as thermal driving medium compared with using liquid water. It can increase to 2 300 W/（m^2 · K） and it is much higher than that of the normal air cooling method （usually at the level of 600-1200 W/（m^2·K））. All fundamental studies of TDHCF show that there actually exists thermal driving in the closed loop small channel in the centrifugal field to improve heat transfer characteristics.
