Novel copolymers with intrinsic microporosity containing tetraphenyl-bipyrimidine for enhanced gas separation

Xiaocui Han,Jianrui Zhang,Cheng Yue,Jinhui Pang,Haibo Zhang,Zhenhua Jiang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.91 No.-

The gas separation of polymers of intrinsic microporosity (PIMs) was enhanced by incorporatingbipyrimidine (bpy) into the polymer (PIM-bpy-x) through the polycondensation of a novel tetraphenyl-bipyrimidine monomer. The structures of PIM-bpy-x were investigated with 1H NMR and FT-IR. Becauseof the excellent heat resistance imparted by the tetraphenyl-bipyrimidine unit, PIM-bpy-x displayedbetter thermal stability than did PIM-1. These polymers displayed large Brunauer-Emmett-Teller (BET)surface areas, ranging from 656 to 728 m2 g 1. The BET surface area of PIM-bpy-5 was 728 m2 g 1, whichwas similar to that of PIM-1 (774 m2 g 1). PIM-bpy-x exhibited excellent gas separation performance. PIM-bpy-5 showed the highest CO2 permeability (5141 barrer), which was much higher than that of PIM-1 (4234 barrer). The increase in CO2 permeability is due to the affinity between the N-rich bipyrimidineunits and CO2. Furthermore, PIM-bpy-x also showed greater resistance to aging than did PIM-1. All of theabove indicate that introducing bipyrimidine units into the polymers can enhance the gas separationperformance of PIMs.

A Dynamic Adjustment Method of Service Function Chain Resource Configuration

( Xiaoyang Han ),( Xiangru Meng ),( Zhenhua Yu ),( Dong Zhai ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.8

In the network function virtualization environment, dynamic changes in network traffic will lead to the dynamic changes of service function chain resource demand, which entails timely dynamic adjustment of service function chain resource configuration. At present, most researches solve this problem through virtual network function migration and link rerouting, and there exist some problems such as long service interruption time, excessive network operation cost and high penalty. This paper proposes a dynamic adjustment method of service function chain resource configuration for the dynamic changes of network traffic. First, a dynamic adjustment request of service function chain is generated according to the prediction of network traffic. Second, a dynamic adjustment strategy of service function chain resource configuration is determined according to substrate network resources. Finally, the resource configuration of a service function chain is pre-adjusted according to the dynamic adjustment strategy. Virtual network functions combination and virtual machine reusing are fully considered in this process. The experimental results show that this method can reduce the influence of service function chain resource configuration dynamic adjustment on quality of service, reduce network operation cost and improve the revenue of service providers.

Energy efficiency optimization of water pump based on heuristic algorithm and computational fluid dynamics

Wang Wenjie,Han Zhenhua,Pei Jin,Pavesi Giorgio,Gong Xiaobo,Yuan Shouqi 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.1

To reduce the energy consumption of large centrifugal pumps, modified heuristic intelligent algorithms are used to directly optimize the diffuser of centrifugal pumps. Considering the hydraulic efficiency under the design condition as the optimization target, in this study, 14 geometric parameters such as the inlet diameter, outlet diameter, and leading and trailing vane angles of the diffuser are selected as design variables, and the modified particle swam optimization and gravitational search algorithm are used to directly search for optimization in the design space. The performance and loss of internal entropy production of the different models before and after optimization are compared and analyzed in detail. The results show that the global optimization ability of the modified algorithm is improved. The diffuser model changes from cylindrical to twisted, the vane wrap angle increases, and the thickness of the leading edge decreases. Under the design condition, the efficiency of modified particle swarm optimization algorithm solution is increased by 2.75% and modified gravitational search algorithm solution by 2.21%, while the power remains unchanged. Furthermore, the optimization solution has the largest lift efficiency improvement under part-load conditions. After optimization, the unstable flow in the model is improved and internal entropy production loss is reduced significantly. The interior of the diffuser is dominated by turbulent entropy production and direct entropy production under different operating conditions, and the wall entropy production accounts for the smallest proportion.

Temperature-constrained topology optimization of nonlinear heat conduction problems

Zhuang Chungang,Xiong Zhenhua,Ding Han 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.4

This paper presents topology optimization of nonlinear heat conduction problems with multiple domains and multiple constraints, including regional temperature and material volume for reducing temperature. Maximum approximation temperatures in the constraint regions are accurately and dynamically calculated, though temperature and temperature-dependent thermal conductivity change with the update of material distribution. A temperature measure with constant error to approximate regional maximum temperature is adaptive to different temperature ranges. A strategy of hole nucleation generation combined with the regional temperature constraints is presented for the level set-based topology optimization. The solid isotropic material with penalization (SIMP) and parametrized level set methods are compared for the temperature-constrained topology optimization. Finally, several numerical examples are solved by the SIMP and parametrized level set methods. The results demonstrate that the proposed approach can obtain intricate topological details and reduce regional temperatures for the nonlinear heat conduction problems.

Influence of gas liquid flow rate ratio on hydrodynamics and mass transfer characteristics of gas-liquid ejector

Tony Suryo Utomo,Jin Zhenhua,ChungSeub Yi,Hyo Min Jeong,Han Shik Chung 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

An investigation on hydrodynamics characteristics of gas liquid ejector has been carried out using to study the influence of gas liquid flow rates ratio on the performance and on the mass transfer characteristic of ejector. In this study, the ejector design was modeled using finite volume CFD techniques to resolve the flow dynamics in the ejectors. The CFD results were validated with available experimental data. Flow field analyses and predictions of ejector performance were also carried out. During validation, although there is a discrepancy between CFD and experimental results, however it has a good agreement in the trend of phenomena respect to experimental results. From the present analysis, it can be concluded that the efficiency of the ejector increases with respect to gas liquid flow rates ratio. It also can be seen that the volumetric mass transfer coefficient is higher when the gas flow rate increased.

The Application analysis of Bubble Pump on Solar Water Heater System

Li Xuesong,Jin Zhenhua,Tony,Han Shik Chung,Hyo Min Jeong 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-

The application analysis of bubble pump on the domestic solar water heater system is presented. The system investigated in this study is a passive device, self pumping and self regulating. It was test to use the bubble pump on solar water heater system. The test experiment has been taken on the existing vacuum tube about the efficiency, working fluid temperature and pressure and circulated power. In order to check the working temperature and working pressure effectively, the bubble pump was test separated from the solar water heater. The equipment consist of the bubble pump, heater and heat exchanger. The main structure of bubble pump was design depend on the character of two phase flow. The complete system was instrumented to measure pressures, temperatures and flow-rates at various locations. The theory analysis of design bubble pump has been given and the experiment design has been included in the paper.

A CFD Analysis on Hydrodynamics Characteristics of Gas-Liquid Ejector

Tony Suryo Utomo,Jin Zhenhua,ChungSeub Yi,Hyo Min Jeong,Han Shik Chung 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-

A CFD investigation on hydrodynamics characteristics of gas liquid ejector has been carried out to study the influence of gas liquid flow rates ratio on the performance and on the mass transfer characteristic of ejector. In this study, the ejector design was modeled using finite volume CFD techniques to resolve the flow dynamics in the ejectors. The CFD results were validated with available experimental data. Flow field analyses and predictions of ejector performance were also carried out. During validation, although there is a discrepancy between CFD and experimental results, however it has a good agreement in the trend of phenomena respect to experimental results. From the present analysis, it can be concluded that the efficiency of the ejector increases with respect to gas liquid flow rates ratio. It also can be seen that the volumetric mass transfer coefficient is higher when the gas flow rate increased.

A CFD Analysis on the Gas-Liquid Ejector

Tony Utomo,Jn Zhenhua,ChungSueb Yi,Hyo Min Jeong,Han Shik Chung 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-

An analysis on the gas-liquid ejector has been carried out using three-dimensional CFD modeling. The purpose of this paper is to study the influence of operating condition and ejector geometries on the hydrodynamics and on the mass transfer characteristic of ejector. The CFD results were validated with available experimental data. Flow field analyses and predictions of ejector performance were also carried out. Variation on the operating conditions was made by varying the gas-liquid flow rate ratio in the range of 0.2 to 1.2. The length to diameter ratio of mixing tube (LM/DM) also varied in the range of 4 to 10. CFD studies show that at LM/DM 5.5, the volumetric mass transfer coefficient increases with respect to gas flow rates. Meanwhile, at LM/DM 4, the plot of volumetric mass transfer coefficient to gas-liquid flow rates ratio reach maximum at gas-liquid flow rates ratio of 0.6. This study also shows that volumetric mass transfer coefficient decrease with respect to the increase of mixing tube length.

The experimental design of a new kind of bubble pump used on the solar water heater system

Li Xuesong,Jin Zhenhua,Han Shik Chung,Hyo Min Jeong 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

The application analysis of bubble pump on the domestic solar water heater system is presented. The system investigated in this study is a passive device, self pumping and self regulating. It was test to use the bubble pump on solar water heater system. The test experiment has been taken on the existed vacuum tube about the efficiency, working fluid temperature and pressure and circulated power. In order to check the working temperature and working pressure effectively, the bubble pump was test separated from the solar water heater. The equipment consists of the bubble pump, heater and heat exchanger. The main structure of bubble pump was design depend on the character of two phase flow. The complete system was instrumented to measure pressures, temperatures and flow-rates at various locations. The theory analysis of design bubble pump has been given and the experiment design has been included in the paper.