To improve the inlet performance of a ramjet working under variable conditions,a design is proposed by controlling the inlet with jet controlling,which combines the method of reducing the sealing Mach number of the ex...To improve the inlet performance of a ramjet working under variable conditions,a design is proposed by controlling the inlet with jet controlling,which combines the method of reducing the sealing Mach number of the external waves and the technique of controlling inlet by jet controlling.Three inlets were designed to analyze the feasibility and a numerical simulation method was used to simulate the three inlet flow fields.The adjustment mechanism of the design was studied through analysis of the simulation results.The design was verified by comparing the performances of the three inlets.The study showed that the method of reducing the sealing Mach number of the external wave system can improve the flow coefficient when the inlet works at low Mach numbers.The technique of controlling inlet by jet controlling can homogenize inlet flow fields at high Mach numbers,reduce effective throat area and increase the total pressure recovery(TPR).Adjustable inlets controlled by jet controlling demonstrate good performance at certain working ranges.展开更多
Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigat...Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigates the design and verification of a new controller to adjust the vehicle height and to regulate the roll and pitch angles of the vehicle body(leveling control) during the height adjustment procedures. A nonlinear mechanism model of the vehicle height adjustment system is formulated to describe the dynamic behaviors of the system. By using mixed logical dynamical(MLD) approach, a novel control strategy is proposed to adjust the vehicle height by controlling the on-off statuses of the solenoid valves directly. On this basis, a correction algorithm is also designed to regulate the durations of the on-off statuses of the solenoid valves based on pulse width modulated(PWM) technology, thus the effective leveling control of the vehicle body can be guaranteed. Finally, simulations and vehicle tests results are presented to demonstrate the effectiveness and applicability of the proposed control methodology.展开更多
文摘To improve the inlet performance of a ramjet working under variable conditions,a design is proposed by controlling the inlet with jet controlling,which combines the method of reducing the sealing Mach number of the external waves and the technique of controlling inlet by jet controlling.Three inlets were designed to analyze the feasibility and a numerical simulation method was used to simulate the three inlet flow fields.The adjustment mechanism of the design was studied through analysis of the simulation results.The design was verified by comparing the performances of the three inlets.The study showed that the method of reducing the sealing Mach number of the external wave system can improve the flow coefficient when the inlet works at low Mach numbers.The technique of controlling inlet by jet controlling can homogenize inlet flow fields at high Mach numbers,reduce effective throat area and increase the total pressure recovery(TPR).Adjustable inlets controlled by jet controlling demonstrate good performance at certain working ranges.
基金supported by the National Natural Science Foundation of China(Grant Nos.51375212,61403172&51305167)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Key Research and Development Program of Jiangsu Province(Grant No.BE2016149)
文摘Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigates the design and verification of a new controller to adjust the vehicle height and to regulate the roll and pitch angles of the vehicle body(leveling control) during the height adjustment procedures. A nonlinear mechanism model of the vehicle height adjustment system is formulated to describe the dynamic behaviors of the system. By using mixed logical dynamical(MLD) approach, a novel control strategy is proposed to adjust the vehicle height by controlling the on-off statuses of the solenoid valves directly. On this basis, a correction algorithm is also designed to regulate the durations of the on-off statuses of the solenoid valves based on pulse width modulated(PWM) technology, thus the effective leveling control of the vehicle body can be guaranteed. Finally, simulations and vehicle tests results are presented to demonstrate the effectiveness and applicability of the proposed control methodology.
