Design and analysis of mechanical flux‑weakening device of axial flux permanent magnet machines

Shaopeng Wang,Jiawei Lu,Bin Li,Chengcheng Liu,Youhua Wang,Gang Lei,Youguang Guo,Jianguo Zhu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

Due to the low inductance of an axial flux permanent magnet machine (AFPMM), the constant power speed regulation range is small. A new mechanical flux-weakening method for single-rotor single-stator AFPMMs is proposed in this paper. By installing a mechanical flux-weakening device on one side of the stator and rotating it certain angle, the speed regulation of the flux-weakening can be realized. The device is simple in structure, easy to operate, and can be operated in the process of machine operation. The validity of the device is verified by applying it to a machine. Finite-element software is used to calculate and analyze the performances of two machines with the device.

Research and practice on oil displacement law of different well pattern in offshore oilfield

Wang Peng,Wang Shaopeng,Zhang Hongyou,Sun Guangyi,Zhai Shangqi,Chang Huijiang,Zhang Chengli 한국자원공학회 2021 Geosystem engineering Vol.24 No.6

BZ oilfield is the first oilfield successfully developed with large-scale horizontal well pattern in Bohai sea. In order to study the well pattern suitable for offshore fluvial sedimentary oilfield, based on the characteristics of offshore oilfield, such as large well spacing, few wells and complex well pattern, the authors designed a set of heterogeneous reservoir models under the guidance of similarity theory. The different well patterns, different displacement rates and different heterogeneity were simulated. The different displacement effects were studied by measuring the electrical characteristics, injection volume, oil production and water production of the model. It is found that the horizontal well pattern is used for low-speed development, the water breakthrough of oil wells is slow in the relatively homogeneous reservoir. In the heterogeneous high permeability reservoir(Jk = 4), the oilfield adopts low-speed development by using staggered well pattern, the water breakthrough of the oil well is slow, and the EOR is large. In the heterogeneous high permeability reservoir(Jk = 6), the oilfield adopts the combined well pattern for low-speed development, the EOR is large. This study deepens the understanding of the development law of horizontal well pattern and the distribution law of remaining oil, and provides a basis for oilfield development and adjustment.

Synthesis of Au Nanoparticles Functionalized 1D α-MoO3 Nanobelts and Their Gas Sensing Properties

Liwei Wang,Shaopeng Wang,Hao Fu,Yinghui Wang,Kefu Yu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.10

A novel sensor material of Au nanoparticles (NPs) functionalized 1D α-MoO3 nanobelts (NBs) was fabricated by a facile lysine-assisted approach. The obtained Au/α-MoO3 product was characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray (EDX), and X-ray photoelectron spectra (XPS). Then, in order to investigate the gas sensing performances of our samples, a comparative gas sensing study was carried out on both the α-MoO3 NBs before and after Au NPs decoration by using ethanol vapor as the molecular probe. The results turned out that, after the functionalization of Au NPs, the sensor exhibited improved gas-sensing characteristics than the pure α-MoO3, such as response and recovery time, optimal operating temperature (OT) and excellent selectivity. Take for example 200 ppm of ethanol, the response/ recovery times were 34 s/43 s and 5.7 s/10.5 s, respectively, while the optimal operating temperature (OT) was lower to 200 ℃ rather than 250 ℃. Besides, the functionalized sensor showed a higher response to ethanol at 200 ℃, and response was 1.6 times higher than the pure MoO3. The mechanism of such improved sensing properties was interpreted, which might be attributed to the spillover effect of Au NPs and the electronic metal-support interaction.

Numerical simulation of three-dimensional flow and heat transfer characteristics of liquid lead-bismuth

He, Shaopeng,Wang, Mingjun,Zhang, Jing,Tian, Wenxi,Qiu, Suizheng,Su, G.H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

Liquid lead-bismuth cooled fast reactor is one of the most promising reactor types among the fourth-generation nuclear energy systems. The flow and heat transfer characteristics of lead-bismuth eutectic (LBE) are completely different from ordinary fluids due to its special thermal properties, causing that the traditional Reynolds analogy is no longer recommended and appropriate. More accurate turbulence flow and heat transfer model for the liquid metal lead-bismuth should be developed and applied in CFD simulation. In this paper, a specific CFD solver for simulating the flow and heat transfer of liquid lead-bismuth based on the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model was developed based on the open source platform OpenFOAM. Then the advantage of proposed model was demonstrated and validated against a set of experimental data. Finally, the simulation of LBE turbulent flow and heat transfer in a 7-pin wire-wrapped rod bundle with the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model was carried out. The influence of wire on the flow and heat transfer characteristics and the three-dimensional distribution of key thermal hydraulic parameters such as temperature, cross-flow velocity and Nusselt number were studied and presented. Compared with the traditional SED model with a constant Pr_t = 1.5 or 2.0, the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model is more accurate on predicting the turbulence flow and heat transfer of liquid lead-bismuth. The average relative error of the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model is reduced by 11.1% at most under the simulation conditions in this paper. This work is meaningful for the thermal hydraulic analysis and structure design of fuel assembly in the liquid lead-bismuth cooled fast reactor.

Study on failure mechanism of line contact structures of nuclear graphite

Jia Shigang,Yi Yanan,Wang Lu,Liu Guangyan,Ma Qinwei,Sun Libin,Shi Li,Ma Shaopeng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

Line contact structures, such as the contact between graphite brick and graphite tenon, widely exist in high-temperature gas-cooled reactors. Due to the stress concentration effect, the line contact area is one of the dangerous positions prone to failure in the nuclear reactor core. In this paper, the failure mechanism of line contact structures composed of IG11 nuclear graphite column and brick were investigated by means of experiment and finite element simulation. It was found that the failure process mainly includes three stages: firstly, the damage accumulation in nuclear graphite material led to the characteristic yielding of the line contact structure, but no macroscopic failure can be observed at this stage; secondly, the stresses near the contact area met Mohr failure criterion, and a crack initiated and propagated laterally in the contact zone, that is, local macroscopic failure occurred at this stage; finally, a second crack initiated in the contact area and developed in to a Y-shape, resulting in the final failure of the structure. This study lays a foundation for the structural design and safety assessment of hightemperature gas-cooled reactors

Effect of infection by Beauveria bassiana on hemolymph and free amino acid in Xylotrechus rusticus

Ding Junnan,Yu Shaopeng,Wang Hui 한국곤충학회 2021 Entomological Research Vol.51 No.7

The purpose of this study was to clarify changes in the immune response of the hemolymph after infection with Beauveria bassiana in Xylotrechus rusticus larvae in order to reveal the physiological regulating mechanism of the pathogenic fungi. The results showed that B. bassiana was infectious to X. rusticus adults. The main infection sites were the thoracic internodes, lower wings, and abdomen. After infection with B. bassiana, the number of blood cells in the X. rusticus larvae was significantly higher than the control. The number of plasma cells and granulocytes in the hemolymph of the insect was largest. The total number of blood cells was mainly affected by the changes in number of plasma cells and granulocytes. The trehalose content in X. rusticus larvae after B. bassiana treatment continued to decrease compared to the control. The glucose content in the larvae hemolymph increased first, then decreased. The acid trehalase activity was significantly higher than the control, and the high activity was maintained for 60–84 h after infection with B. bassiana. Nineteen kinds of free amino acids were detected in the larvae hemolymph infected by B. bassiana. After infection, the total amount of free amino acids in the larvae hemolymph presented a trend where the amount first declined, then rose. Proline, arginine, and glutamine were the main amino acids required for the growth and development of B. bassiana in X. rusticus larvae. The amount of hemolymph and free amino acids played an important role in immunity during the infection with B. bassiana.

A new model and testing verification for evaluating the carbon efficiency of server

Liang Guo,Yue Wang,Yixing Zhang,Caihong Zhou,Kexin Xu,Shaopeng Wang 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.10

To cope with the risks of climate change and promote the realization of carbon peaking and carbon neutrality, this paper first comprehensively considers the policy background, technical trends and carbon reduction paths of energy conservation and emission reduction in data center server industry. Second, we propose a computing power carbon efficiency of data center server, and constructs the carbon emission per performance of server (CEPS) model. According to the model, this paper selects the mainstream data center servers for testing. The result shows that with the improvement of server performance, the total carbon emissions are rising. However, the speed of performance improvement is faster than that of carbon emission, hence the relative carbon emission per unit computing power shows a continuous decreasing trend. Moreover, there are some differences between different products, and it is calculated that the carbon emission per unit performance is 20-60KG when the service life of the server is five years.

Effects of Lactobacillus helveticus Fermentation on the Ca2+ Release and Antioxidative Properties of Sheep Bone Hydrolysate

Keguang Han,Jing Cao,Jinghui Wang,Jing Chen,Kai Yuan,Fengping Pang,Shaopeng Gu,Nairui Huo 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.6

Both the calcium and collagen in bone powder are hard to be absorbed by the body. Although enzymatic hydrolysis by protease increased the bio-availability of bone powder, it was a meaningful try to further increase Ca2+ release, oligopeptide formation and antioxidant activity of the sheep bone hydrolysate (SBH) by lactic acid bacteria (LAB) fermentation. Lactobacillus helveticus was selected as the starter for its highest protease-producing ability among 5 tested LAB strains. The content of liberated Ca2+ was measured as the responsive value in the response surface methodology (RSM) for optimizing the fermenting parameters. When SBH (adjusted to pH 6.1) supplemented with 1.0% glucose was inoculated 3.0% L. helveticus and incubated for 29.4 h at 36℃, Ca2+ content in the fermented SBH significantly increased (p<0.01), and so did the degree of hydrolysis and the obtaining rate of oligopeptide. The viable counts of L. helveticus reached to 1.1×1010 CFU/mL. Results of Pearson correlation analysis demonstrated that LAB viable counts, Ca2+ levels, obtaining rates of oligopeptide and the yield of polypeptide were positively correlated with each other (p<0.01). The abilities of SBH to scavenge the free radicals of DPPH, OH and ABTS were also markedly enhanced after fermentation. In conclusion, L. helveticus fermentation can further boost the release of free Ca2+ and oligopeptide, enhance the antioxidant ability of SBH. The L. helveticus fermented SBH can be developed as a novel functional dietary supplement product.

Study on three-dimensional numerical simulation of shell and tube heat exchanger of the surface ship under marine conditions

Liao Yi,Cai Qi,He Shaopeng,Wang Mingjun,Xiao Hongguang,Gong Zili,Wang Cong,Jia Zhen,Feng Tangtao,Qiu Suizheng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Shell-and-tube heat exchanger (STHX) is widely used by virtue of its simple structure and high reliability, especially in a space-constrained surface ship. For the STHX of the surface ship, roll, pitch and other motion of the ship will affect the heat transfer performance, resistance characteristics and structural strength of the heat exchanger. Therefore, it is urgent to carry out numerical simulation research on three-dimensional thermal hydraulic characteristics of surface ship STHX under the marine conditions. In this paper, the numerical simulation of marine shell and tube heat exchanger of surface ship was carried out using the porous media model. Firstly, the mathematical physical model and numerical method are validated based on the experimental data of a marine engine cooling water shell and tube heat exchanger. The simulation results are in good agreement with the experimental results. The prediction errors of pressure drop and heat transfer are less than 10% and 1% respectively. The effect of marine conditions on the heat transfer characteristics of the heat exchanger is investigated by introducing the additional force model of marine condition to evaluate the effect of different motion parameters on the heat transfer performance of the heat exchanger. This study could provide a reference for the optimization of marine heat exchanger design.

Five Forces Model of Computational Power: A Comprehensive Measure Method

Meixi Wu,Liang Guo,Xiaotong Yang,Lina Xie,Shaopeng Wang 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.7

In this paper, a model is proposed to comprehensively evaluate the computational power. The five forces model of computational power solves the problem that the measurement units of different indexes are not unified in the process of computational power evaluation. It combines the bidirectional projection method with TOPSIS method. This model is more scientific and effective in evaluating the comprehensive situation of computational power. Lastly, an example shows the validity and practicability of the model.