Compromise Optimal Design using Control-based Analysis of Hypersonic Vehicles

Liu, Yanbin,bing, Hua The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.2

Hypersonic vehicles exhibit distinct dynamic and static characteristics, such as unstable dynamics, strict altitude angle limitation, large control bandwidth, and unconventional system sensitivity. In this study, compromise relations between the dynamic features and static performances for hypersonic vehicles are investigated. A compromise optimal design for hypersonic vehicles is discussed. A parametric model for analyzing the dynamic and static characteristics is established, and then the optimal performance indices are provided according to the different design goals. A compromise optimization method to balance the dynamic and static characteristics is also discussed. The feasibility of this method for hypersonic vehicles is demonstrated.

Study of Mechanism of Counter-rotating Turbine Increasing Two-Stage Turbine System Efficiency

Liu, Yanbin,Zhuge, Weilin,Zheng, Xinqian,Zhang, Yangjun,Zhang, Shuyong,Zhang, Junyue Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.3

Two-stage turbocharging is an important way to raise engine power density, to realize energy saving and emission reducing. At present, turbine matching of two-stage turbocharger is based on MAP of turbine. The matching method does not take the effect of turbines' interaction into consideration, assuming that flow at high pressure turbine outlet and low pressure turbine inlet is uniform. Actually, there is swirl flow at outlet of high pressure turbine, and the swirl flow will influence performance of low pressure turbine which influencing performance of engine further. Three-dimension models of turbines with two-stage turbocharger were built in this paper. Based on the turbine models, mechanism of swirl flow at high pressure turbine outlet influencing low pressure turbine performance was studied and a two-stage radial counter-rotation turbine system was raised. Mechanisms of the influence of counter-rotation turbine system acting on low-pressure turbine were studied using simulation method. The research result proved that in condition of small turbine flow rate corresponding to engine low-speed working condition, counter-rotation turbine system can effectively decrease the influence of swirl flow at high pressure turbine outlet imposing on low pressure turbine and increases efficiency of the low-pressure turbine, furthermore increases the low-speed performance of the engine.

Study of Mechanism of Counter-rotating Turbine Increasing Two-Stage Turbine System Efficiency

Yanbin Liu,Yangjun Zhang,Weilin Zhuge,Xinqian Zheng,Shuyong Zhang,Junyue Zhang 한국유체기계학회 2013 International journal of fluid machinery and syste Vol.6 No.3

Two-stage turbocharging is an important way to raise engine power density, to realize energy saving and emission reducing. At present, turbine matching of two- stage turbocharger is based on MAP of turbine. The matching method does not take the effect of turbines' interaction into consideration, assuming that flow at high pressure turbine outlet and low pressure turbine inlet is uniform. Actually, there is swirl flow at outlet of high pressure turbine, and the swirl flow will influence performance of low pressure turbine which influencing performance of engine further. Three-dimension models of turbines with two-stage turbocharger were built in this paper. Based on the turbine models, mechanism of swirl flow at high pressure turbine outlet influencing low pressure turbine performance was studied and a two-stage radial counter-rotation turbine system was raised. Mechanisms of the influence of counter-rotation turbine system acting on low-pressure turbine were studied using simulation method. The research result proved that in condition of small turbine flow rate corresponding to engine low-speed working condition, counter-rotation turbine system can effectively decrease the influence of swirl flow at high pressure turbine outlet imposing on low pressure turbine and increases efficiency of the low-pressure turbine, furthermore increases the low-speed performance of the engine.

Study on Through-flow Model for Turbine System Considering Three-dimensional Flow Field Distortion Effect

Yanbin Liu,Weilin Zhuge,Yangjun Zhang,Shuyong Zhang 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.4

Turbocharging is an important way to raise engine power density, save energy and reduce emission. Because turbocharger is driven by exhaust gas, energy utilization rate is a key factor for turbocharged engine performance. As a part transferring heat to mechanical energy, turbine efficiency decides exhaust gas energy utilization. Because of three-dimensional flow field distortion effect at outlet to exhaust manifold, turbine efficiency will be different from MAP when engine working. Influences by interaction in turbine system, turbine efficiency will decrease. So in order to evaluate turbine operating performance and design or select turbine more precisely, it is necessary to build a through-flow model for turbine which can consider three-dimensional flow field distortion effect. Unsteady flow field distortion at outlet to turbine was analyzed and flow field interaction law between exhaust manifold and turbine was studied. On the basis, six typical flow field distortion models in an engine operation cycle were raised. Then influences six models on each flow stage in turbine were analyzed. Further, models for exhaust manifold and turbine were built separately. Difference between unsteady three-dimensional simulation result and that based on turbine system through-flow model was compared and analyzed. Research result illustrated that difference of turbine cycle efficiency was only 0.1% and difference of turbine cycle work was 0.3%. So it can be deduced that turbine system through-flow model can predict turbine operation performance precisely and help turbine system matching exactly.

Robotic Path Planning Based on a Triangular Mesh Map

Yanbin Liu,Yuanyuan Jiang 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.10

Aiming at the problem of robot path planning in complex maps, an algorithm of robot path planning based on a triangular grid graph is proposed. Firstly, a weighted undirected loop graph and a feasible domain of nodes are obtained by discretizing the triangular mesh map. Next, the Dijkstra search algorithm is applied to find the feasible shortest path from an initial to a final configuration. Finally, The Douglas-Peucker algorithm is applied to remove duplicate and redundant nodes in the feasible path, and the waypoint is extracted. The final path is a curve that is obtained by connecting the several extracted waypoint. The proposed algorithm is tested for various maps. Compared with the probabilistic roadmap method, the experimental results show that the proposed method can overcome the shortcomings of the random sampling method. Furthermore, the experimental result of triangular mesh map method used in two labyrinth maps show that the triangular mesh map method can solve the robot path planning problem in complex map very well, and it is an excellent algorithm for robot path planning.

Compromise Optimal Design using Control-based Analysis of Hypersonic Vehicles

Yanbin Liu,Hua bing 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.2

Hypersonic vehicles exhibit distinct dynamic and static characteristics, such as unstable dynamics, strict altitude angle limitation, large control bandwidth, and unconventional system sensitivity. In this study, compromise relations between the dynamic features and static performances for hypersonic vehicles are investigated. A compromise optimal design for hypersonic vehicles is discussed. A parametric model for analyzing the dynamic and static characteristics is established, and then the optimal performance indices are provided according to the different design goals. A compromise optimization method to balance the dynamic and static characteristics is also discussed. The feasibility of this method for hypersonic vehicles is demonstrated.

STUDY ON THE METHOD FOR ENGINE TECHNICAL STATE CHANGE TREND PRECIPITATION BASED ON COMBINATION FORECASTING MODEL

Jianmin Liu,Yanbin Liu,Fuzhou Feng 한국소음진동공학회 2008 한국소음진동공학회 국제학술대회논문집 Vol.2008 No.7

Back-Calculation Method of Rock Mass Pressure in a Shallow-Buried Super Large-Span Tunnel Using Upper-Bench CD Method

Yanbin Luo,Yunfei Wu,Jianxun Chen,Fangfang Dong,Weiwei Liu,Lijun Chen,Yao Li,Zhou Shi 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.1

Rock mass pressure has always been a research hotspot in the field of tunnel engineering, especially in the super large-span tunnel, which is characterized by flat section, large excavation span, and complex stress field. Based on the Letuan Tunnel (a bi-directional tunnel with eight traffic lanes) of Binlai expressway expansion project in Shandong Province, China, this paper focused on the calculation method of rock mass pressure and the evolution law of load release in the construction process of the super large-span tunnel excavated by upper-bench central diaphragm (CD) method. Based on field measured data of Letuan Tunnel, the deformation behavior of primary lining and the distribution state of rock mass pressure during the tunnel construction were analyzed. According to the bearing mode of supporting structure, the mechanical models of different construction stages were established. Then, the rock mass pressures in different construction stages were back-calculated using mechanical models and compared with the measured values, and the evolution law of load release during the tunnel construction was discussed. The study results show that the tunnel deformation and rock mass pressure were significantly affected by the construction process and support form, and the excavation span was the key factor affecting the stability of rock mass. For the shallow-buried super large-span tunnel constructed by upper-bench CD method, the primary support of upper bench was under eccentric pressure. The comparison between the back-calculated value and the field measured value indicated that they were similar, and the average relative error was 17.23%. According to the concept of load release coefficient proposed in this paper, the load release coefficient after the pilot tunnel ahead (Part I) excavation reached 63%, and the load release coefficient after the pilot tunnel behind excavation (Part II) was 37%, which means that the rock mass pressure of Part I is increased about 59% due to the excavation of Part II.

Solution-based synthesis of PEDOT:PSS films with electrical conductivity over 6300 S/cm

Yanbin Shi,Yuqin Zhou,Rongzong Shen,Fengzhen Liu,Yurong Zhou 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

Poly(3,4-ethylenedioxythiophene) mixed with poly (styrenesulfonate) (PEDOT:PSS) is considered as oneof the most valuable conductive polymers due to its high conductivity, transparency and mechanicalflexibility. Many experiments have proved that H2SO4 post-treatment is an effective way to enhance theelectrical conductivity of PEDOT:PSSfilms. Here we reported a method for the fabrication of PEDOT:PSSfilms with conductivity as high as 6323.9 364.5 S/cm, based on a two-step H2SO4 post-treatment. Thisvery high conductivity is, as far as we know, the highest reported value for PEDOT:PSSfilms by solutionpreparation. The removal of PSS and redox reaction are the keys to enhance the conductivity of PEDOT:PSSfilms.

Implementation of SHM system for Hangzhou East Railway Station using a wireless sensor network

Yanbin Shen,Wenwei Fu,Yaozhi Luo,Chung Bang Yun,Dun Liu,Pengcheng Yang,Guang Yang,Guangen Zhou 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.1

Structural health monitoring (SHM) is facilitated by new technologies that involve wireless sensor networks (WSNs). The main benefits of WSNs are that they are distributed, are inexpensive to install, and manage data effectively via remote control. In this paper, a wireless SHM system for the steel structure of Hangzhou East Railway Station in China is developed, since the state of the structural life cycle is highly complicated and the accompanying internal force redistribution is not known. The monitoring system uses multitype sensors, which include stress, acceleration, wind load, and temperature sensors, as the measurement components for the structural features, construction procedure, and on-site environment. The sensor nodes communicate with each other via a flexible tree-type network. The system that consists of 323 sensors is designed for the structure, and the data acquisition process will continue throughout its whole life cycle. First, a full-scale application of SHM using a WSN is described in details. Then, it focuses on engineering practice and data analysis. The current customized WSN has been demonstrated to have satisfactory durability and strong robustness; hence, it well satisfies the requirements for multi-type sensors to operate in a large area. The data analysis results demonstrate that the effects of the construction process and the environment on the super-large-scale structure have been captured accurately. Those effects include the stress variation throughout the construction process, the dynamic responses that are caused by passing trains, the strain variation caused by temperature change over the long term, and the delay in the wind-pressure history.