Numerical simulation on flow field characteristics of the four cylinder engine cooling system and its performance improvement

Libin Tan,Yuejin Yuan 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

The comprehensive performance evaluation procedure and overall performance evaluation indices for the four cylinder engine cooling systems are proposed in this work and the four cylinder engine cooling system with two different flow patterns are investigated. Coolant velocity distributions of nose bridge area sections of cylinder head water jacket and plane section of cylinder block water jacket in series flow pattern cooling system meet the coolant flow velocity requirements of 1.5 m/s in high-temperature area. Coolant velocity distributions of water jacket in parallel flow pattern cooling system is relatively lower and not meet the velocity requirements of 1.5 m/s. Through the improvement of pump performance, the system coolant flowrate in parallel flow pattern cooling system can be increased to 90 L/min. After velocity uniformity improvement of water jacket, the coolant velocity distributions in parallel flow cooling system become more uniform. Coolant velocity and heat transfer coefficient of high temperature area both meet the design requirements of coolant velocity 1.5 m/s and heat transfer coefficients of 5000 W/(m 2 ·K). The cooling performance for the engine with parallel flow pattern cooling system is significantly improved and meets the cooling design requirements.

Numerical simulation on flow field of motor annular water jacket and its cooling performance optimization

Libin Tan,Yuejin Yuan 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

Aiming at improving the cooling of motor annular water jacket, the effects of different water jacket designs and pump rotation speed and epoxy resin filling on the flow field characteristics and motor temperature distribution were studied. Results show that uneven flow distribution leads to high temperature of motor coil and large temperature gradient. The optimized water jacket has better flow, uniform flow distribution of long and short paths, higher utilization rate of coolant, and the coil temperature is 2 °C lower than that of original model. On the basis of optimized water jacket, when epoxy resin filling methodology and pump rotation speed increased to 5000 r/min are applied, the coil temperature can be reduced by 16 °C compared with the original model. From the cooling performance optimization results in current case, the improvement order from the smallest to the biggest is the optimization of motor water jacket flow field, optimization of motor water jacket system flow rate, and the epoxy resin filling. To meet the cooling demands of motor, the comprehensive effects from the aspects of reducing coolant system resistance, increasing pump speed, epoxy resin filling and other effective technologies are ought to be considered for all case studies.

CFD simulation and optimization on airflow uniformity of material drying room used in steam blanching and hot-air vacuum drying equipment

Dong Wang,Libin Tan,Yuejin Yuan,Yuming Lu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.10

Airflow velocity uniformity in material drying room used in steam blanching and hot-air vacuum drying equipment is crucial for obtaining a good drying quality of fruits and vegetables. To analyze the airflow velocity uniformity and give the optimization design for improving the airflow uniformity, CFD method is used for the flow field analysis of material drying room and the velocity non-uniformity coefficient is used as the evaluation indicator for the velocity uniformity. Results show that the airflow velocity distribution in the material drying room at the original inlet airflow distribution chamber is relatively uneven and the airflow velocity nonuniformity coefficient in drying area is 34 %. For reducing the airflow velocity non-uniformity, the airflow velocity distribution of three structural modification directions with 12 designs in total are analyzed and compared. The minimum airflow velocity non-uniformity coefficient for adding a spoiler model, reducing the closed end width and adding nozzle baffles are 17.1 %, 30.2 %, 10.4 %, respectively. Through comparison, adding the nozzle baffle with a width of 11 mm at the rear end of each nozzle outlet is considered as the optimal designs to conduct the experimental validation. Experimental validation results shows the the relative error between the simulated value and the measured value is within 10 %, proving that the CFD prediction results is reliable and the research results can give a theoretical reference for the designers to evaluate and optimize the structure of inlet airflow distribution chamber for improving the airflow uniformity in drying area.

Rocaglamide-A Potentiates Osteoblast Differentiation by Inhibiting NF-κB Signaling

Aiguo Li,Libin Yang,Xiaolin Geng,Xingmei Peng,Tan Lu,Yanjun Deng,Yuzheng Dong 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.11

Rheumatoid arthritis is a chronic inflammatory disease that leads to bone and cartilage erosion. The inhibition of osteoblast differentiation by the inflammatory factor TNF-α is critical for the pathogenesis of rheumatoid arthritis. To modulate TNF-α mediated inhibition of osteoblast differentiation is required to improve therapeutic efficacy of rheumatoid arthritis. Here, we explored the potential role of rocaglamide-A, a component of Aglaia plant, in osteoblast differentiation. Rocaglamide-A prevented TNF-α mediated inhibition of osteoblast differentiation,and promoted osteoblast differentiation directly,in both C2C12 and primary mesenchymal stromal cells. Mechanistically, Rocaglamide- A inhibited the phosphorylation of NF-κB component p65 protein and the accumulation of p65 in nucleus, which resulted in the diminished NF-κB responsible transcriptional activity. Oppositely, overexpression of p65 reversed rocaglamide-A’s protective effects on osteoblast differentiation. Collectively, rocaglamide-A protected and stimulated osteoblast differentiation via blocking NF-κB pathway. It suggests that rocaglamide-A may be a good candidate to develop as therapeutic drug for rheumatoid arthritis associated bone loss diseases.

Rocaglamide-A Potentiates Osteoblast Differentiation by Inhibiting NF-κB Signaling

Li, Aiguo,Yang, Libin,Geng, Xiaolin,Peng, Xingmei,Lu, Tan,Deng, Yanjun,Dong, Yuzheng Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.11

Rheumatoid arthritis is a chronic inflammatory disease that leads to bone and cartilage erosion. The inhibition of osteoblast differentiation by the inflammatory factor TNF-${\alpha}$ is critical for the pathogenesis of rheumatoid arthritis. To modulate TNF-${\alpha}$ mediated inhibition of osteoblast differentiation is required to improve therapeutic efficacy of rheumatoid arthritis. Here, we explored the potential role of rocaglamide-A, a component of Aglaia plant, in osteoblast differentiation. Rocaglamide-A prevented TNF-${\alpha}$ mediated inhibition of osteoblast differentiation, and promoted osteoblast differentiation directly, in both C2C12 and primary mesenchymal stromal cells. Mechanistically, Rocaglamide-A inhibited the phosphorylation of NF-${\kappa}B$ component p65 protein and the accumulation of p65 in nucleus, which resulted in the diminished NF-${\kappa}B$ responsible transcriptional activity. Oppositely, overexpression of p65 reversed rocaglamide-A's protective effects on osteoblast differentiation. Collectively, rocaglamide-A protected and stimulated osteoblast differentiation via blocking NF-${\kappa}B$ pathway. It suggests that rocaglamide-A may be a good candidate to develop as therapeutic drug for rheumatoid arthritis associated bone loss diseases.

Preparation of the Water-Soluble Fluorene-Containing Fluorescent Polymer by One-Pot Method

Yuan Wang,Hongchi Zhao,Haijian Tan,Xiaomeng Li,Yunxia Qian,Libin Bai,Yonggang Wu,Shufang Lv 한국고분자학회 2015 Macromolecular Research Vol.23 No.10

A water-soluble fluorescent polymer, 2,7-di{4'-[3''-(S-poly(acryloyl ethylene diamine hydrochloride)-2'''- methyl propionic acid)propionyloxy hexyloxy]phenyl}-9,9-di(n-octyl)fluorene (P3) with regular and ordered structure, was designed and synthesized with high conversion using click reaction between thiols and carbon-carbon double bonds. Because the S-H bond is relatively weak, thiol groups are subject to rapid oxidation during purification and storage and thereby result in the low conversion in the following click reaction. To circumvent this limitation, the synthesis of thiol groups and click reaction were simultaneously performed in one system (one-pot method). The intermediate products P1 (S-1-dodecyl-S'-[poly(N-Boc-acryloyl ethylene diamine)-2'-methyl propionic acid]trithiocarbonate) and M2 (2,7-di[4-(acryloyloxy hexyloxy)phenyl]-9,9-di(n-octyl)fluorene) were prepared via reversible addition fragmentation chain transfer (RAFT) polymerization and Williamson synthesis, respectively. Then, 2,7- di{4'-[3''-(S-poly(N-Boc-acryloyl ethylene diamine)-2'''-methyl propionic acid)propionyloxy hexyloxy]phenyl}- 9,9-di(n-octyl)fluorene (P2) was synthesized with high conversion (83%) by employing a click reaction with P1 and M2 as starting materials. Finally, water-soluble fluorescent polymer P3 was obtained after the deprotection of P2. M2, P1, P2 and P3 were characterized by Fourier transform infrared (FTIR) spectrum, nuclear magnetic resonance (NMR), high-resolution mass spectroscopy (MS), gel permeation chromatograph (GPC), UV-Visible (UV-Vis) spectrum, and fluorescence, respectively. The results revealed that P3 displayed good solubility in water and not only exhibited a blue fluorescence emission band in water but also had a similar photoluminescent spectra to those of M2 and P2 in dichloromethane. The fluorescence quantum yield of P3 in aqueous solution could reach 0.10. In addition, the result of cell cytotoxicity indicates that P3 has low cytotoxicity and exhibits potential for biomedical applications. This work provides a new insight into the study of water-soluble fluorescent polymer.

An Optimization Model for Low Carbon Oriented Modular Product Platform Planning (MP3)

Qi Wang,Dunbing Tang,Leilei Yin,Inayat Ullah,Libin Tan,Tao Zhang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.1

Consumers, industry, and government entities put more focus on the global warming. With this point in view, enterprises have started to take into account of the low carbon idea to develop products. Recently, lots of firms are using the Modular Product Platform Planning (MP3) between product generations for the rapid update of products with lesser production costs and time to market. Traditionally, MP3 mainly concerns on module sharing between product generations in modular planning, but pays no attention to the environmental concern which becomes an important design criterion due to the rising awareness of environmental protection. In this paper, an optimization model for low carbon oriented MP3 is presented. To support low carbon oriented MP3, this article proposed a probability approach to evaluate the scheme of modular planning for MP3. Meanwhile, a measurement method for low carbon performance of modular planning is provided. Then, an optimization model for low carbon oriented MP3 is formulated to determine the modular planning in pursuit of maximizing the low carbon performance of the product with controlling the implementation probability of MP3. Furthermore, an Adaptive Memetic Algorithm (AMA) is developed for solving the optimization problem. Finally, a case study is proposed to validate the effectiveness of the proposed approach.